AUXILIARY EQUIPMENT

• Document Type: FOIA
• Collection: FOIA Collection
• Document Number (FOIA) /ESDN (CREST): 06535939
• Release Decision: RIFPUB
• Original Classification: U
• Document Page Count: 58
• Document Creation Date: December 28, 2022
• Document Release Date: August 10, 2017
• Case Number: F-2014-00925

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Al2 Section IV
UXILIARY EQUIPMENT
TABLE OF CONTENTS
Communications and Associated
Page
Autopilot System
Page
4-27
Electronic Equipment
4-1
Navigation Equipment
4-32
Birdwatcher Equipment
4-21
Inertial Navigation System
4-36
Lighting Equipment
4-25
Periscope
4-51
Flight Recorder
4-25
Destruct System
4-56
Dictet Tape Recorder
4-27
COMMUNICATION AND ASSOCIATED
ELECTRONIC EQUIPMENT
The communication, electronic navigation
and instrument approach equipment includes
the following:
AN/ARC-50 UHF Communication,
direction finding and ranging equip-
ment.
DF 203 ADF Receiver
AN/ARN-52 TACAN Equipment
ILS Equipment
HF (618T) Radio Equipment with
Sel-Call Decoder
Birdwatcher Equipment
IFF Equipment
AN/AIC-18 Interphone Equipment
AN/ARC-50 UHF RADIO NAVIGATION SYSTEM
AN/ARC-50 equipment is capable of trans-
mitting and receiving on any of 3500 channels
In the frequency range of 225.00 to 399.95
MC. The equipment can be operated in
either of two basic modes; an internal (nar-
row band) mode in which its operation is
compatible with any conventional UHF radio
communication set, and an external (wide
band) mode in which it has high resistance
to jamming and low detectability. In this
mode it incorporates message privacy and
range measurement functions. When used
in conjunction with the UHF DF system and
AN/ARA-50 set it provides direction finding
capability in either mode.
In the internal mode power output is a nom-
inal 30 watts minimum while in the enternal
mode the power output is approximately 50
watts. The power output in either mode may
be reduced in 10 steps of 9 db increments
to a fraction of a watt.
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UHF RADIO PANELS AND INDICATORS
0
ANGE
MILES
0
0
RANGE INDICATOR
J249-1
10
BEARING DISTANCE HEADING INDICATOR ( BDH I
SIGNAL DATA TRANSLATOR
CONTROL PANEL
RECEIVER - TRANSMITTER
CONTROL PANEL
1 POWER SELECTOR SWITCH
8
2 POWER SELECTOR INDICATOR
9
3 INTERNAL - EXTERNAL SW ITCH
4 MANUAL FREQUENCY SELECTOR
10
SWITCHES AND INDICATORS
11
5 TONE BUTTON
12
6 FUNCTION SELECTOR SWITCH
13
7 PRESET CHANNEL SELECTOR SWITCH
14
15
12
3513-1
15
PRESET CHANNEL INDICATOR
MANUAL - PRESET - GUARD
SELECTOR AND INDICATOR
VOLUME CONTROL KNOB
CODE SELECTOR SWITCHES
RANGE ADDRESS SW ITCH
RANGE INTERROGATE SW ITCH
CONTINUOUS RANGE SWITCH
RESPONSE LIGHT
Figure 4-1
13
14
F200-2910
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Most of the AN/ARC-50 equipmentis
mounted in the pressurized and cooled nose
compartment and includes the blower cooled
translator group, the receiver-transmitter
group and a separate inverter. AN/ARA-50
direction finding equipment and the flush
antenna are also mounted in the nose com-
partment.
The AN/ARC-50 control panels are mounted
on the pilot's left console. A range indicator
is mounted on the instrument panel. The di-
rection finding equipment is also connected
to the No. 1 needle of the BDHI when the
equipment is operating. The communi-
cation antenna is mounted in the lower right
chine. Power for the equipment is pro-
vided by the essential dc bus. The left gen-
erator bus supplies blower and heater power.
SIGNAL DATA TRANSLATOR CONTROL PANEL
The translator control panel labeled UHF
COMM is located on the left console. It in-
corporates provisions for control of fre-
quency and power output, mode of operation
and receiver volume. It provides the pilot
with 20 preset frequency channels, provi-
sion for manually selecting any of 3500 fre-
quencies and controls for operation of the
separate fixed tuned guard channel receiver.
Function Selector Switch
This four position rotary switch is labeled
OFF, MAIN, BOTH and ADF. In the OFF
position the equipment is not energized. In
the MAIN position the translator group
equipment is energized with only the trans-
mitter and main receiver operative. In the
BOTH position the equipment is energized
with the transmitter and both main and
guard receivers are operative. In the ADF
position the AN/ARA-50 equipment is en-
ergized and the main receiver and the
transmitter are operative. The No. 1
needle of the BDHI is also disconnected
from the DF 203 ADF receiver or TACAN
receiver and receives directional signals
from the ARA-50 equipment.
Manual-Preset-Guard Selector Lever and
Indicator
This selector lever controls the manner of
frequency selection. In the MANUAL (left)
position the manual frequency selector
switches are activated and the frequency
selected is visible in the cutouts above each
switch. In the PRESET (center) position
the preset channel selector switch is acti-
vated and the channel selected is displayed
in the window below the Preset indicator.
In the GUARD (right) position the guard
channel frequency is set on the main re-
ceiver and transmitter, and GUARD is in-
dicated in the window below the selector
lever knob.
Preset Channel Selector Switch
This switch, located in the center of the
panel, selects one of twenty preset fre-
quencies when the manual preset guard se-
lector knob is positioned to PRESET and in-
dicates the frequency channel selected in
the window beneath the Preset indicator.
The channel numbers are blanked out when
MANUAL or GUARD is selected.
Frequency Selector Switches and Indicators
Five rotary switches across the top of the
panel permit manual selection of any one of
3500 frequencies in the 225.00 to 399.95 mc
range. These switches are activated when
the manual-preset-guard selector knob is
positioned to MANUAL. Each switch is
used to select the digit displayed in the cut-
out above.
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INT-EXT Mode Switch
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Tone Button
This two position switch is labeled INT-
EXT. In the INT position the translator
transmits and receives narrow band AM
signals independent of the receiver-trans-
mitter equipment. This position is used
for conventional UHF transmitting and re-
ceiving. In the EXT position the signal
translator and receiver-transmitter are
used together to receive and transmit the
wind band pseudo-noise encoded signals.
The EXT position is also used for direction
finding and/or ranging functions. The
power selector switch may be used to re-
gulate the transmission power in either
position. �
Power Selector Switch and Indicator
The rotary switch is the larger of the two
concentric knobs and controls the output of
the transmissions from the translator and
receiver-transmitter combination. It has
ten positions labeled 1 to 10 to permit set-
ting power output from the maximum of 30
watts (10) to a low of .3 microwatts (1) in
9 db increments in the INT or narrow band
mode. In the EXT or wide band mode power
is increased to a maximum of 50 watts
but also may be reduced in the 9 db units to
approximately 1.0 microwatt. The digit in
the cutout above the knob indicates the
power output selected. The A position, pro-
viding for an additional amplifier, is oper-
ative but power output is the same as the 10
position.
Volume Control
This is the smaller center knob concentric
with the power selector switch and adjusts
the audio level of the receivers. Clock-
wise rotation will increase volume.
This button is located on the right side of
the panel. When depressed, a 1020 cycle
'tone is produced for audio checking or
transmission on either INT or EXT mode.
RECEIVER-TRANSMITTER CONTROL PANEL
The receiver-transmitter control panel lo-
cated just aft of the translator control on
the left console is used when operating in
the external or ,wide band mode only. In
this mode of operation the AN/ARC-50 pro-
vides the following functions:
1. Secure voice communications.
2. Semi Automatic Direction Finding.
3. Semi Automatic Range Measurement.
4. Automatic Ranging.
5. Automatic Ranging and Direction
Finding.
The panel contains rotary selector and
range address switches with position indi-
cators, pushbutton interrogation and con-
tinuous ranging switches and indicating
lights and a separate response indicator
light. These switches and lights are only
operative when the INT-EXT mode switch
is in the EXT position.
Code Selector Switches
Five rotary type digital indicating selector
switches labeled SEL are provided on the
panel. The digital window type indicators
have positions labeled from 0 to 7. Com-
municating stations must have identical
code selecting settings in order to establish
wide band communication.
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NOTE
In this installation only the 1st
and 5th selector switches are
operative giving 64 possible code
selections. 2nd and 3rd selector
switches must be on 0 and the 4th
select switch must be on 6.
Range Address Switch
The inboard or 6th rotary selector switch
labeled ADRS-RGE is used for selective
ranging. It has eight positions which show
position indications of 1 thru 5 inclusive for
5 possible range addresses. The other
three positions are labeled A, 0, and T.
The A position allows for a range measure-
ment on any terminal regardless of its ad-
dress (ADRS-RGE) code. This is con-
sidered an emergency code. The 0 position
is an off position which prevents another
terminal from ranging although voice com-
munication capability is retained. The T
position is a test position for checking in-
dicator lights on the translator and re-
ceiver transmitter panels.
Range Interrogate Switch and Indicator Light
This pushbutton switch containing an integral
light is used to make interrogation of direc-
tion and range in the external mode. When
the translator function selector switch is in
the ADF position the one time bearing read-
ing will be indicated on the No. 1 needle of
the BDHI. If the translator function switch
is in the MAIN or BOTH position pressing
the INT button will provide a one time range
measurement in nautical miles and tenths.
Normal time for one time directional or
range indication is 3 seconds. The button
Is also used to establish automatic ranging
and automatic ranging and direction finding
in combinations with the CONT button. The
button will be momentarily depressed and
the light illuminated while the ranging or
direction range is being obtained. The light
will be extinguished after approximately 3
seconds.
Continuous Range Switch
This pushbutton switch and integral light
labeled CONT, when pressed, sets the re-
ceiver-transmitter into a continuous auto-
matic ranging or combination ranging and
DF conditions. This condition is activated
by the interrogate button provided that the
other station has previously activated their
continuous range operation. The light is
illuminated at both stations while continu-
ous ranging or ranging and DF operation is
in effect. The range indicator and No. 1
needle of the BDHI will be updated every 5
seconds. Either station pressing its CONT
button or MIC button will terminate the
automatic cycle. When the cycle is com-
pletely broken the range indicators will re-
turn to 000.0 miles.
Response Light
The response light, labeled RESP, will be
Illuminated when the AN/ARC-50 is answer-
ing a range measurement interrogation frOm
another aircraft or station.
DISTANCE INDICATOR
The distance indicator is mounted on the
upper left side of the instrument panel and
displays the distance between two ranging
AN/ARC-50 sets. Negative contact will re-
sult in a 000.0 reading.
UHF ANTENNAS
The UHF communication antenna is located
on the lower right chine and remains ex-
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9. Volume control - As desired.
tended. Provisions are available to hy-
draulically retract the antenna flush. The
UHF-ADF antenna is mounted on the bottom
of the nose compartment and is the receiv-
ing antenna at any time the function switch
on the translator is in the ADF position. It
is optimized for the DF function and com-
munications and ranging will be inferior
when using this antenna for other than the
direction finding function.
NORMAL OPERATION
Internal Mode UHF Communications
1. Microphone selector switch - UHF.
2. Function switch - MAIN or BOTH.
3. INT-EXT switch - INT.
4. Power selector switch - Set.
5. MANUAL-PRESET-GUARD lever - As
desired.
NOTE
If GUARD is selected frequency
selection will be automatic.
If MANUAL:
6. Frequency selector switches - Set.
If PRESET:
7. Channel selector switch - Set.
8. Mic button - Press.
External Mode UHF Encoded Communication
NOTE
External mode is applicable only
when communication is with
another AN/ARC-50 station.
1. Microphone selector switch - UHF.
2. Function switch - MAIN or BOTH.
3. INT-EXT switch - EXT.
4. Power selector switch - Set.
5. MANUAL-PRESET-GUARD lever -
MANUAL or PRESET as desired.
NOTE
If GUARD is selected communi-
cations will be in the narrow band
conventional mode even though
LNT-EXT switch is in EXT.
If MANUAL:
6. Frequency selector switches - Set.
If PRESET:
7. Channel selector switch - Set.
8. Code selector switches - Set.
9. Range address switch - 0 or as desired.
10. Mic button - Press (tone will be heard
for approximately 1 second).
11. Volume control - As desired.
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Semi Automatic Ranging
A one time range interrogation is made as
follows:
1. Select proper frequency and power.
2. Function switch - MAIN or BOTH.
3. INT-EXT switch - EXT.
4. Code Selector switch - Set.
5. ADRS-RGE selector switch - Set.
6. INT button - Press. Light will illum-
inate for approximately 3 seconds.
When the light extinguishes range indication
may be read.
To update range reading:
7. INT- Press.
To communicate with range partner:
8. Mic button - HOLD. Wait for tone to
mute.
Automatic Ranging
Automatic continuous ranging with both sta-
tions receiving continuously updated range
information every 5 seconds is accomplished
as follows:
1. Frequency and power - Set.
2. Function switch - MAIN or BOTH.
3. INT-EXT switch - EXT.
4. Code selector and range address
switches - Set.
5. Request selected range partner to
press CONT button.
6. CONT button - Press.
7. INT button - Press.
8. CONT light - Check on.
9. INT and RESP light - Check alternate
illumination. Both stations will re-
ceive updated range readings every 5
seconds.
NOTE
After a continuous range is estab-
lished, if a ranging interrogation
cycle is not completed, the equip-
ment will automatically re-inter-
rogate once. The digital range in-
dication will be held during this
period for approximately 10 seconds
and, if ranging is not re-established,
then reset to zero.
To resume communication:
10. Mic button - Press. Tone will be
heard for 0-10 seconds depending on
which part of the ranging cycle is in
progress.
NOTE
First transmission after muting
will be to ranging partner only.
Subsequent transmissions will be
heard by all stations having iden-
tical code selections.
11. Volume control - Adjust.
ADF Operation
During ADF operation the AN/ARA-50
equipment and directional antenna are used
for receiving, and the direction of signals
from the responding UHF station will be in-
dicated by the No. 1 needle of the BDHI.
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Internal Mode Direction Finding
For DF operation in conventional narrow
band mode proceed as follows:
1. Select proper frequency and power.
2. Function switch - ADF.
3. INT-EXT switch - INT.
4. Request communicating station for con-
tinuous transmission or tone.
5. Bearing to transmitting station will be
indicated by the BDHI No. 1 needle.
External Mode Direction Finding
For semi automatic or one time ADF bear-
ing proceed as follows:
1. Select proper frequency and power.
2. Function switch - ADF.
3. INT-EXT switch - EXT.
4. Code selector switch - Set.
5. Range address switch - Set.
6. INT button - Press momentarily. Light
will illuminate for approximately 3
seconds. When light is extinguished,
bearing will be indicated by the BDHI
No. 1 needle.
To update bearing:
7. INT button - Press.
To resume communication:
8. Mic button - HOLD.
For continuous updated ranging and auto-
matic direction bearing proceed as above
except:
1. Request ranging partner to press
CONT button.
2. CONT button - Press.
3. INT button - Press.
NOTE
Holding the Mic button until tone
stops (0-8 seconds one way ADF
and 0-12 seconds two way ADF)
terminates the automatic ranging
and ADF functions. The CONT
and INT buttons will re-establish
the continuous ranging and ADF
cycles.
BEARING, DISTANCE, HEADING INDICATOR
(BDHI)
The bearing, distance, heading indicator
located on the left side of the instrument
panel contains a rotating compass card, a
range shutter labeled OFF covering the di-
gital distance readout, and No. 1 and No. 2
directional indicating needles. The card
displays true or magnetic heading depend-
ing on the position of the INS mode switch.
In the NAY position, true heading using the
INS as a reference will be indicated at the
lubber line. In the FRS position, magnetic
heading from the FRS will be indicated. The
No. 1 needle will read an ADF bearing from
the DF 203 unless the AN/ARC 50 is op-
erating in the ADF mode; or TACAN bear-
ing depending on the position of the No. 1
needle selector switch. The No. Z needle
will indicate the steering direction from
the INS. When reliable TACAN information
is being received the range shutter will be
up and the range readout will represent
slant range to the TACAN station being in-
terrogated.
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HF RADIO PANEL
1 FREQUENCY SELECTOR SWITCHES
2 FREQUENCY INDICATOR
3 RF SENSITIVITY CONTROL
4 SERVICE SELECTOR SWITCH
Figure 4-2
3513- 7
Fno-41(b)
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BDHI No. 1 Needle Selector Switch
This two position switch is located on the
right console. It selects either the TACAN
or DF-203 ADF inputs to the No. 1 BDHI
needle, provided the AN/ARC-50 is not op-
erating in the ADF mode. In the TACAN
(forward) position, the No. 1 needle of the
BDHI is connected to the TACAN receiver
and the needle indicates the bearing to the
selected TACAN station. In the ADF (aft)
position, the No. 1 needle indicates the
bearing to the selected station. When the
AN/ARC-50 is operating in the ADF function,
the switch is inoperative and the No. 1
needle indicates the bearing to the selected
ARC-50 station.
COURSE INDICATOR (ID 249)
The ID-249 course indicator is installed on
the center instrument panel. It is used in
conjunction with the BDHI to indicate course
deviation when operating the TACAN system.
It is also used to indicate course and glide
slope deviation and marker beacon passage
when operating the 1LS receivers. The in-
dicator contains a course set knob, a course
selector window to show course selected, a
vertical CDI course deviation needle
and dot deviation scale, a horizontal glide
slope indicator needle and dot deviation
scale, (GS1), a TO-FROM indicator window,
GSI & CDI warning flags (OFF), a heading
pointer with right and left pointer scales
and a marker beacon light. The indicator
is powered by signals from the respective
receivers.
6181 HF RADIO EQUIPMENT
The 618T is a long range airborne single
side band (SSB) voice communications
transceiver which transmits and receives
in the 2 to 30 megacycle range. The trans-
ceiver can be tuned in one kilocycle steps.
The primary operating mode is SSB, using
either the upper or lower side of the modu-
lated signal, which allows all the power to
amplify the side band selected. The equip-
ment can also transmit and receive AM
signals.
The equipment consists of the transceiver
with an antenna tuner which is mounted in
the pressurized nose compartment. The
antenna is the pitot boom and insulated for-
ward portion of the aircraft nose. This
equipment has been modified to use fixed
frequency ac power from the No. 1 inverter
for those circuits which are frequency
critical and variable frequency ac power
normally furnished from the left generator
for non-critical main ac power. A fre-
quency sensing relay is provided to transfer
this main ac power source if the left or op-
erative generator bus drops below 325
cycles (4500 engine rpm) to the ARC-50 in-
verter if the COMM selector switch is in
the HF position. Control circuit power is
supplied by the essential dc bus.
6181 HF Control Panel (714 E-2)
The control panel for the HF equipment is
located on the left console and contains the
following:
Service Selector Switch
This switch turns the equipment on or off
and selects the desired operating mode.
In the USB (upper side band) position, only
the upper side band signal is transmitted
or received. This is the sum of the voice
signal and the radio frequency (rf) signal.
In the LSB (lower side band) position, only
the lower side band signal is transmitted or
received. This signal is the difference of
the voice signal and the rf signal. In the
AM position the signal is amplitude modu-
lated and both side bands and the original
rf signal are transmitted and received.
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Frequency Selector Switches
The first switch selects the proper megacy-
cle point as indicated by the digits in the
first two windows. It will indicate from 02
to 29. The frequency will increase as the
knob is rotated clockwise and decrease as
the knob is rotated counterclockwise.
The 100 kc knob selects the proper one
hundred kilocycle point and indicates from
0 to 9 in the third window. The 10 kc knob
selects the desired ten kilocycle point and
indicates from 0 to 9 in the fourth window.
The one kc knob selects the desired one
kilocycle point and indicates from 0 to 9 in
the right window.
Volume Knob
This knob is used to adjust the audio level
in the headphones.
NORMAL OPERATION
1. Service selector switch - Set to desired
mode. This will turn the equipment on.
For normal voice communication this
may be USB, LSB or AM.
2. Frequency selector switches - Set to
desired operating frequency. The
muting of sound in the headphones will
Indicate the equipment is setting to the
new frequency.
Note
The service selector switch may
have been moved from the OFF
position to an operating mode
with the desired operating fre-
quency already set up. In this
case, rotate the ten kc select
knob one digit off frequency and
then back to the operating fre-
quency. This will allow the
equipment to return to the de-
sired frequency.
3. COMM selector switch - HF.
When background sound is again heard in
the headphone:
4. TRANS-button - Press. Wait for the
equipment to tune - a 1000 cps tone will
be heard until tuning is complete.
When the equipment is tuned (no 1000 cps
tone):
5. VOL knob - Adjust so that background
noise in headphones is barely audible.
EMERGENCY OPERATION
If a short circuit exists in the output of the
power supply, a protective circuit turns off
the equipment. Restore to operation as
follows:
1. Service selector switch - OFF, then
back to desired operating mode.
NOTE
When the antenna coupler is re-
quired to complete several con-
secutive tuning cycles, a thermal
relay will de-energize the equip-
ment. Restore to operation as
follows:
1. Service selector switch - OFF.
After two minutes the thermal
relay will cool.
2. Service selector switch - To de-
sired operating mode.
If HF and/or BW operation is required with
inoperative engines or generators:
1. HF & BW power switches - On.
2. COMM selector switch - HF.
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NOTE
The COMM selector switch must be
In the HF position to provide con-
tinuous HF or BW communication
with windmilling engines and/or in-
operative generators. In this posi-
tion automatic transfer of main ac
power from the left generator to
the ARC-50 inverter is accomplished
if the frequency of the left generator
bus drops below 325 cycles or 4500
engine rpm. At below 2800 engine
rpm or 200 cycles the automatic bus
transfer occurs and if the right
engine or generator bus is above
325 cycles (4500 engine rpm) the
irequency relay will reconnect the
main ac power to the right gen-
erator power source.
SEL CALL DECODER
The Sel Call Decoder provides a convenient
method for the selective reception of HF
transmissions. It will recognize a call on
a selected channel of the HF receiver and
unmute the receiver when the proper call
signal is received. The decoder operates
in a preset Sel Call coder frequency and will
recognize only this channel. A momentary
contact switch and indicating light is on the
left console to MUTE or UNMUTE the HF
audio circuit. The indicator light is illum-
inated when the decoder is in the muted
mode. The Sel Call Decoder is also auto-
matically unmuted when the transmitter key
is pressed which provides audio sidetone
during transmission to the pilot's headset.
Power for the Sel Call Decoder is furnished
by the dc essential bus.
X BAND BEACON
The aircraft is equipped with an X band
beacon and an EGG beacon. The X band
beacon transponder is located in the nose
compartment with the flush antenna mounted
on the lower fuselage just aft of the nose
boom. The EGG beacon transponder and
antenna are mounted on the lower Q-bay
hatch. Both beacons are controlled by a
3 position toggle switch located on the left
console. The switch is labeled EGG-OFF-
TNKR. Power for the transponder is fur-
nished by the dc essential bus.
TACAN SYSTEM AN/ARN-52
The TACAN system provides continuous in-
dications of bearing and slant distance to a
selected surface beacon or to another air-
craft containing the necessary transponder
equipment. The system transmits inter-
rogation pulses which trigger responding
pulses from the selected ground station or
aircraft. Slant distance to the station or
aircraft is computed from the elapsed time.
Both bearing and distance are visually dis-
played on the bearing, distance heading in-
dicator on the instrument panel. The sys-
tem is capable of operation on any one of
the 216 channels and has a range of about
300 nautical miles. The transmitting fre-
quency range is 1025 to 1150 megacycles.
Frequency ranges for reception are; low
band normal, 926-1024 megacycles, air to
air 1088-1150 megacycles; high band nor-
mal, 1151-1213 megacycles, air to air
1025-1087 megacycles. Power for the
equipment is furnished by the left ac gen-
erator and essential dc buses.
AN/ARN-52 Control Panel
A control panel is installed on the right con-
sole. The panel contains a channel selec-
tor switch, mode selector switch and a
volume control.
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SECTION IV
TACAN CONTROL PANEL AND INDICATORS
DETAIL C
COURSE INDICATOR
7063
7063
DETAIL A
BEARING DISTANCE HEADING INDICATOR (BDHI)
Figure 4-3
Channel Selector Switch
A channel selector is used to select any one
of the available channels. Selection is ac-
complished by setting the desired number
in the channel window using the concentric
knobs. The outer knob selects the first
two digits and the inner knob selects the
third digit of a desired channel.
Volume Control Knob
Audio level of the TACAN station identifi-
cation signals is increased by rotating the
volume (VOL) control clockwise.
Mode Selector Switch
The mode selector switch has four positions.
DETAIL B
TACAN CONTROL PANEL
OFF - The set is de-energized.
FZ00-66(a)
REC - The set is energized and presents
bearing and course information on
the BDHI and course indicator.
TIP - Same as the PEG position and also
presents range in nautical miles to a
TACAN station on the BDHI.
A/A Same as the PEG position and also
presents range in nautical miles
and bearing to another properly
equipped aircraft.
OPERATION OF THE TACAN SYSTEM
1. INS mode switch - FRS if operative.
2. TACAN mode selector switch - REC.
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ILS CONTROL PANEL
1 TO-FROM INDICATOR
2 GLIDE SLOPE SIGNAL OFF FLAG
3 BEARING SELECTOR INDICE
4 LOCALIZER-VOR OFF FLAG
5 MARKER BEACON LIGHT
6 COURSE DEVIATION NEEDLE (C. D. I.
7 HEADING INDICATOR
10
14 12
8 GLIDE SLOPE INDICATOR (GSI)
9 BEARING SELECTOR KNOB
10 FREQUENCY INDICATOR
11 AUDIO IDENTIFICATION CUTOUT
12 FREQUENCY SELECT' SWITCH
13 ILS ON LIGHT
14 VOLUME-ON-OFF SWITCH
Figure 4-4
11
12
13
F200-31(a)
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Allow 90 seconds for warmup:
3. Channel selector switch - Desired
channel.
4. Adjust VOL as desired and verify sta-
tion identification.
5. No. 1 needle selector switch - TACAN.
6. Observe bearing pointer on BDHI: To-
From indication on course indicator.
7: Mode selector switch - T/R, or A/A.
8. Observe range to station or aircraft on
BDHI.
Bearing, Distance, Heading Indicator (BDHI)
No. 1 Needle
The BDHI No. 1 needle may be connected
to the TACAN receiver by the BDHI No. 1
needle selector switch. If the receiver is
tuned to a TACAN station, the No. 1 needle
will indicate the bearing to the station.
Refer to BDHI this section.
ILS EQUIPMENT
ILS equipment consisting of localizer, glide
slope and marker beacon receivers are
provided for ILS approaches. In addition
the equipment includes a control panel and
indicating light, the ILS converter and as-
sociated antennas. Localizer, glide slope
and marker beacon signals are reflected on
the ID-249 course indicator. Localizer
signals are not reflected by the No. 1 needle
of the BDHI which continues to show TACAN
or HF/UHF ADF bearings as selected.
The localizer receiver tunes odd tenth mega-
cycle localizer frequencies between 108.10
to 111.90 mc. It will also tune VOR voice
or tone signals between even tenths from
108.0 to 112.0 and all tenths between 112.1
thru 117.9 mcs.VOR signals will not be re-
flected on the ID-249 course indicator. The
associated glide slope frequencies between
329.3 to 335 megacycles will be automati-
cally tuned when the receiver is tuned to
the desired localizer frequency. The lo-
calizer ON-OFF-VOL control also activates
the fixed tuned 75 megacycle marker beacon
receiver and marker beacon signals are re-
flected by coded audio tones in the headset
and coded flashes of the single marker
beacon light on the ID-249 course indicator.
As the marker beacon antenna is located on
the inside of the nosewheel door the marker
beacon will only be usable with the landing
gear down. The ILS ON light is provided
to indicate that the localizer is furnishing
signals to the ID-249 course indicator and
that TACAN signal inputs are disconnected
from that instrument. TACAN bearing and
range to selected stations will still be avail-
able on the BDHI. All receivers are solid
state and operate with power furnished by
the essential dc bus.
ILS Control Panel
The ILS control panel is located on the
lower right side of the instrument panel.
The panel controls consist of a ON-OFF-
VOL control concentric with a larger fre-
quency (megacycle) selector on the left side
of the panel. The small knob turns the ILS
equipment from off to on and further clock-
wise rotation will increase the volume of
voice reception or tone identification. The
larger knob selects the 3 digit megacycle
frequency of the desired localizer station
which is indicated in the window in the
center of the panel. The right hand side
control knobs are also concentric with the
small center knob to eliminate tone iden-
tification from the headset. The larger
concentric knob controls the 2 digit tenths
and hundreth mc frequency selector which
is indicated in the frequency window. The
ILS ON light is located just above the panel
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ADF CONTROL PANEL
1 LOOP CONTROL
2 BFO SWITCH
3 TUNE-FOR-MAX INDICATOR
4 TUNING CONTROL
5 BAND SELECTOR SWITCH
6 FREQUENCY INDICATOR WINDOW
7 GAIN CONTROL
8 FUNCTION SWITCH
Figure 4-5
3-16-65
FMA12-45
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and indicates that the TACAN receiver is
disconnected from the ID-249 course indi-
cator and course and glide slope deviation
indications are from the LLS equipment.
Operation of I LS
1. ON-OFF-VOL switch - ON.
2. Desired localizer frequency - Select.
3. Volume - Adjust.
4. Localizer station - Identify.
5. Front course heading - Select.
6. ILS light - Check ON.
7. Glide slope and localizer warning flags-
Check not visible.
DF-203 ADF RECEIVER
The DF-203 ADF radio receiver is an auto-
matic or manual direction finder and a low
and broadcast range aural receiver. The
equipment consists of a radio receiver, a
control unit, a flush sense antenna, a flush
fixed loop antenna, a BDHI and the connect-
ing cabling, antenna coupler and a quadrantal
error corrector. The receiver covers a
frequency range of .19 to 1.75 megacycles
in three bands. Power for the equipment
is furnished by the essential dc bus and the
26-volt instrument transformer.
ADF Control Panel
The ADF control panel is installed on the
right console of the cockpit. The controls
are described below.
Function Switch
The function switch is the larger of the two
concentric knobs on the inboard side of the
panel. The labeled positions are OFF,
ADF, ANT and LOOP. In the OFF position
the equipment is de-energized. In the ADF
position the equipment functions as an auto-
matic direction finder with a continuous in-
dication of the bearing to the radio station
shown on the BDHI if the AN/ARC-50 is
not operating in the DF mode. In this posi-
tion both the sense and loop antennas are
connected to the receiver. In the ANT posi-
tion, received signals are obtained only
from the sense antenna and the equipment
functions as a conventional aural radio re-
ceiver. In the LOOP position received sig-
nals are obtained only from the loop anten-
na and the equipment functions as a manual
direction finder to enable the pilot to deter-
mine the bearing to the radio station by
aural null procedures.
Band Selector Switch
The band selector switch is the larger of
the concentric knobs located in the outboard
side of the control panel and is used to se-
lect the desired frequency band. The cor-
rect frequency scale will also appear in the
frequency indicator window for the band
selected as follows:
Band Frequency Coverage
.19 - .40 MC 190 - 400 KC FAA
Low Frequency Band
.40 - .84 MC
400 - 840 KC Interna-
tional Distress Frequency
and Lower Broadcast
Band
.84 - 1.75 MC 840 - 1750 KC Upper
Broadcast Band
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Tuning Control
The tuning control is the smaller of the out-
board concentric knobs and tunes the re-
ceiver within the frequency band selected.
The timed frequency is indicated on the
scale of the frequency indicator. The con-
trol is also rotated slightly for maximum
reading on the tuning meter.
Loop Control
The control labeled LOOP is used to ac-
complish the electrical equivalent of ro-
tating the loop (gonio) antenna. The control
is labeled L and R and the left or right ro-
tation effect will be apparent in the headset
and the tuning meter. The speed of the ro-
tating effect may be slowed by turning the
loop control approximately half way to the
L or R labeled position.
Gain Control
The gain control is the smaller of the in-
board aoncentric knobs and is provided to
adjust the audio level of the receiver.
BFO Switch
The BFO switch when in the BFO position
provides a beat frequency oscillator to aid
in tuning the receiver or to receive coded
transmissions.
Bearing, Distance, Heading Indicator
(BDHI) No. 1 Needle
ADF bearing indication is provided by the
No. 1 needle of the BDHI when the BDHI
No. 1 needle selector switch is in the HF/
UHF (aft) position and the AN/ARC-50 ADF
Is not operating. Refer to BDHI, this sec-
tion.
NORMAL OPERATION
Operation of the ADF Receiver as a
Conventional Radio Receiver
1. Function switch - ANT.
2. Band selector switch - Select desired
band.
3. Tuning control - Rotate to desired
frequency and adjust for maximum
reading on the tuning meter.
4. Volume - Adjust as desired.
5. The BFO switch can be used to tune in
continuous wave signals or to zero
beat modulated signals.
Operation of the ADF Receiver as an
Automatic Direction Finder
1. Tune receiver as above and positively
Identify the station.
2. Function switch - ADF.
3. Tuning control - Time for maximum
signal reading on tuning meter.
4. BDHI No. 1 needle selector switch -
ADF (aft).
5. Read bearing to station on BDHI No.
1 pointer.
Operation of the ADF Receiver as a
Manual Direction Finder (Aural Null)
1. Tune receiver as above and postively
identify the station.
2. Tuning control - Tune for maximum
signal reading on tuning meter.
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3. BDHI No. 1 needle selector switch -
ADF (aft).
4. Function switch - Loop.
5. Loop control - R or L, as necessary,
to acquire null.
NOTE
If the AN/ARC-50 ADF function is
operating, the No. 1 BDHI needle
will remain connected to the UHF
equipment.
TRANSPONDER (IFF) - 914-X-1
The 914-X-1 transponder provides recep-
tion, detection, decoding, encoding and
transmission of signals in the IFF Mark X
(SIF) system and has a locally installed
MODE X discrete operating function. The
transponder will also recognize a Mode 4
interrogation; however, the set will not de-
code or encode a reply without accessory
equipment. Any one of numerous coded re-
plies available for Modes 1, Mode 3 or X
can be selected by rotating the appropriate
selector switches on the panel. The set is
capable of transmitting an emergency reply
regardless of the interrogation mode. A
provision is also incorporated to identify
position of the aircraft. Power for the set
is furnished by the essential dc bus. Addi-
tion of the Mode X capability deletes the
Mode 2 function from the transponder.
TRANSPONDER (I FF) CONTROL PANEL
The transponder control panel is installed
on the upper left console. The panel con-
tains two code selectors for Mode 1 and
Mode 3/X codes, Mode 1 and Mode 3 toggle
switches, an I/P switch, IFF power selec-
tor switch and an emergency switch bar.
Power Switch
The IFF power switch has three positions:
Off, LO, and ON. When the switch is
placed in the LO position only local (strong)
Interrogations are recognized and answered.
With the switch in the ON position, there is
full sensitivity for recognition and reply.
The IFF power switch activates Mode X
when in the ON or LO position. Response
to Mode 1 and Mode 3 interrogations depends
on the position of the Mode 1 and 3 toggle
switches. When the Emergency switch bar
is up, the power switch is forced to the ON
position. A 30 second time delay is incor-
porated in the power switching before the
equipment is operative.
Mode Switches
Two two-position mode switches, one for
Mode 1 and one for Mode 3, control trans-
mission of Mode 1 and Mode 3 replies.
Correctly coded interrogations will be an-
swered when a mode has been made active
by selecting the J.N position. When a Mode
1 or Mode 3 switch is in the OUT position,
that mode is not active and does not trans-
mit upon interrogation except in Emergency.
Mode X is active at all times when the power
switch is in the ON or LO position and is�
not affected by the Mode 1 or Mode 3 toggle
switch positions.
Code Selectors
Two rotating type code selectors are pro-
vided. The code selector for Mode 1, con-
sists of two rotary digital indicating
switches. The first digit window will indi-
cate 0, 1, 2, 3, 4, 5, 6, or 7. The second
digit window will indicate 0, 1, 2, or 3.
The Mode 3/X code selector will indicate 0,
1, 2, 3, 4, 5, 6, or 7 for each digital win-
dow. The mode 3 code selection also con-
trols the Mode X code transmission.
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IFFIS IF CONTROL PANEL
1 MODE 1 CODE SELECTORS
2 IDENTIFICATION OF POS ITION ( I /13 ) SWITCH
3 MODE 3/X CODE SELECTORS
4 MODE 3 SWITCH
5 IFF POWER SWITCH
6 EMERGENCY SWITCH BAR
7 MODE I SWITCH
Figure 4-6
REV 2-19-65
FMA12-32 (b )
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Emergency Switch Bar
The emergency switch bar, when placed in
the EMERGENCY up position, operates two
toggle switches that controls emergency
response and also pushes the IFF power
switch to the ON position if it is in the off
or LO position. When the emergency bar
is in the up position an emergency indi-
cating pulse group (code 7700) is transmitted
on Mode X each time an interrogation is
made on Mode X. Mode 1 and 3 are also
turned on by the emergency bar irrespective
of the position of the Mode 1 and 3 In-Out
switches. In the EMERGENCY position
Mode 1 will respond on the code selected
but Mode 3 will respond on code 7700 irre-
spective of code selected.
NOTE
The ground radar scope indication
from this transponder is coded in
a different manner than the normal
AN/APX-46 transponder.
Identification of Position Switch
The identification-of-position (I/P) switch
is used to control transmission of I/P pulse
groups. The switch has three positions;
MIC, OUT and a spring-loaded I/P position.
When the switch is momentarily in the I/P
position, the I/P timer is energized for 30
seconds. If an interrogation is recognized
on any active mode within this 30 second
period, VP replies will be made. When
the switch is in the OUT position, trans-
mission of the I/P pulse groups is withheld.
The MIC position is inoperative.
OPERATION OF THE IFF SYSTEM
1. Power switch - ON or LO.
2. Emergency bar - Down.
3. Mode 1 and Mode 3 IN-OUT switches -
As required.
'NOTE
Mode X operation is continuous
when the power switch is in the LO
or ON position. For secure IFF
operation, both the Mode, 1 and
Mode 3 toggle switches must be in
the OUT position.
4. I/P switch - As required.
5. Code selectors - As required.
To make an emergency response to Mode
1, Mode 3 and Mode X interrogations:
6. Emergency bar - Push up.
B1RDWATCHER EQUIPMENT
Birdwatcher (BW) is an automatically op-
erating aircraft monitoring system with
data link from the aircraft to .ground sta-
tions by means of HF radio transmissions.
The BW senses each of 40 items. If the
condition of any of these items becomes
abnormal with respect to preset limits
(figure 4-7) it causes the 618T HF radio to
transmit one set of coded signals on the
frequency in effect at that time. The coded
signals are not repeated until another ab-
normality occurs or unless the first con-
dition is corrected and becomes abnormal
again. The coded signals consist of three
consecutive 1/2 seconds bursts, each sepa-
rated by a five second quiet period. Each
transmission includes an aircraft identifi-
cation code and the status of all items
sensed. The signal bursts are normally
transmitted regardless of the microphone
switch, communications selector switch,
or radio control panel settings if the HF
radio is on. The BW signal can be heard by
the pilot as a chirp or noise burst in his
headset. The pilots HF voice communi-
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A-12
B 1 RD WATCHER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
38.39,40
B-W SIP
TEST ON
CC%1
OFF OFF
c-c- �
CODE A ACTIVITY CODE B
Items monitored by B-W
Both generators out
Both TB out
Altitude low
Fuel quantity low
Destruct system activated
L fuel flow low
R fuel flow low
L hyd pressure low
R hyd pressure low
System B gz H active
A hyd press low
B hyd press low
Both LOX systems low
System A active
L CIT temp high
R CIT temp high
System B active
Figure 4-7
Level at which system transmits
AC power to both busses off
Excessive pitch acceleration
Excessive yaw acceleration
Cockpit pressure
Seat ejected
Code A
Code B
Excessive nose up angle of attack
L nacelle
R nacelle
System C
System F
fire warning
fire warning �
active
active
R EGT high - Derich on
L EGT high - Derich on
Aircraft identification
FZ00-48(b)
Less than 70000 + 1500 feet
Below 3000 to 6000 pounds (tank 1 & 4)
Arm & destruct switches on
Less than 7500 pph
Less than 7500 pph
1700 psi .5 sec delay
1700 psi .5 sec delay
2200 psi +0 -150 zero time delay or less
than 1 gal.
2200 psi zero time delay
Less than 50 psi or 1 liter
Greater than 440oC + 5oC.
Greater than 440�C�+ 5�C
+ 6g
+ 2g
Greater than 30,200 + 1100 feet
More than 140 nose up
1050 + 50oF
1050 �+ 50�F
860 + 5�C
860 + 5�C
Figure 4-7
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cation capability is cut off for the 1/2-second
transmission periods, but BW normally does
not otherwise interfere with any pilot com-
munication capabilities on HF or UHF chan-
nels or on tanker intercom. The BW system
operation requires that the HF radio be op-
erating. Power for the BW equipment is
furnished by the essential dc bus.
Birdwatcher Control Panel
The BW control panel is located on the
right console immediately ahead of the cir-
cuit breaker panel. Controls consist of a
power ON-OFF-ECM TEST toggle switch,
Code A and Code B pushbutton switches and
an activity light. The power switch turns
on or deactivates the BW equipment. With
BW power ON, placing the switch in the
ECM TEST position should produce a signal
code burst in the pilots headset, but it will
not result in a signal transmission. Op-
eration of the A or B pushbutton transmits
a distinctly coded signal. By convention,
transmission of the "A" signal indicates
that the pilot is aware that the condition of
a monitored item is or has been abnormal,
but that there is no emergency. Also by
convention, transmission of a "B" signal
confirms the pilots awareness of an abnor-
mal or emergency situation. Other con-
ventions may be substituted.
AN/AIC -18 INTERPHONE
An AN/A1C-18 interphone control panel is
located behind the pilot's seat. The panel
contains a Call knob, Normal-Aux-Listen
switch and a Volume control knob. Due to
the location of the panel, the volume control
must be preset prior to flight. No On-Off
switch is provided and the equipment is op-
erative whenever the essential dc bus is
energized.
Call Knob
The call knob is inoperative.
Normal-Aux-Listen Switch
The Normal-Aux-Listen switch has two
positions; NORMAL and AUX LISTEN. The
NORMAL position allows all audio signals
to pass through the AN/AIC-18 amplifier.
The volume control knob on the AN/AIC-18
panel is used to adjust the audio signal in-
tensity. The AUX LISTEN position by-
passes the amplifier and audio intensity
must be adjusted with the individual equip-
ment volume control. The switch is safety-
wired to the NORMAL position.
Microphone Switch
A transmitter-interphone mircophone switch
is installed on the control stick. The mo-
mentary TRANS position (up) is used for
UHF, or HF depending on the position of
the microphone selector switch on the left con-
sole. The INPH position (down) provides
interphone operation for communication with
the ground crew and A/R interphone during
refueling contact. This position is also used
to activate the dictet recorder for pilot com-
ments if recorder switch is in RECORD
position.
Throttle Microphone Button
A microphone button is provided on the
right throttle for use during taxi, takeoff
and landing when the nose steering must be
held engaged. This is a pushbutton switch
which must be held down for radio trans-
mi s s ion.
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Communication Selector Switch
A three position rotary switch labeled
COMM located on the left console selects
the radio or interphone to which the micro-
phone output will be connected. In the HF
position the microphone output will be con-
nected to the 618T HF radio. This position
also automatically provides ARC 50 ac
inverter power to the HF when the left gen-
erator is below correct frequency. In the
UHF (center) position the microphone output
is connected to the ARC 50 UHF radio. The
right position labeled SIL disconnects the
microphone from all transmitters to prevent
inadvertent transmissions. The microphone
connection to the interphone system and to
the tanker is through the refueling probe
and is accomplished by using the normal
INTPH position.
I FR Volume Control
The IFR volume control is located on the
upper left console and when turned clock-
wise increases the interphone audio volume.
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EXTERIOR LIGHTING
Beacon and Fuselage Lights
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INTERIOR LIGHTING
Two retractable lights are located near the
midpoint of the fuselage. One is on the top
of the fuselage and the other on the bottom.
When the lights are retracted they are flush
with the fuselage contour and when turned
on will show a white light from above and
below. The lights will extend approximately
two inches,and, when in this position and
turned on, the red lights and reflectors ro-
tate at 45 rpm, giving the effect of 90 flashes
per minute. The lights are powered by the
essential dc bus and the rotating and re-
tracting mechanism is powered by the No.1
inverter.
Beacon and Fuselage Light Switch
This three position switch is located at the
forward end of the upper left console. In
the center OFF position the lights are re-
tracted and turned off. In the BCN LTS
(forward) position the lights extend, illum-
inate and rotate. Extension and retraction
time is approximately 30 seconds. In the
FUS LTS (aft) position the white lights il-
luminate in the retracted position.
Landing and Taxi Lights
A 1000 watt landing light and a 450 watt taxi
light are mounted on either side of the nose
gear strut. Power for the lights is fur-
nished by the left generator bus.
Landing and Taxi Light Switch
A luminous (3 dot) switch located on the left
side of the instrument panel operates the
landing and taxi lights. The switch has
three positions; LAND (up), TAXI LT (down)
and OFF (center).
Cockpit Lighting System
SECTION IV
The instruments and consoles are illumi-
nated with edge and post lighting. In addi-
tion, two flood lights are provided on each
side of the cockpit and a utility spotlight is
mounted above each console. The spot-
lights are detachable and may be moved
about the cockpit. Rheostats on the aft end
of the spotlights are used to vary their in-
tensity. Each spotlight is provided with a
pushbutton switch which enables the pilot
to obtain maximum brillance without use of
the rheostat. Red or white light may be se-
lected by rotating the lens color selectors
on the front of the lights. Power for the
instrument and console lights is furnished
by the left generator bus. Power for the
floodlights and utility spotlights is furnished
by the essential dc bus.
Cockpit Light Switches
Rheostat type instrument and panel light
switches are located on the cockpit left
console. Ten rotary positions are avail-
able to vary light intensities from OFF to
BRT. The floodlight switch located on the
outboard side of the right console varies
the intensity of both lights from OFF to
BR T.
FLIGHT RECORDER
An automatic, continuously operating flight
recorder is normally mounted in the right
chine of the aircraft to record airspeed,
altitude, vertical acceleration, heading and
elapsed time on an aluminum foil tape. The
recorder has its own pitot static system
which may also be used as an alternate for
the normal pitot-static system. Heading
information for the recorder is furnished
by the FRS compass system. Ac electrical
power from the No. 3 inverter is used to
keep a spring motor wound so that all in-
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FLIGHT RECORDERS
To be furnished when available
Figure 4-8
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FLIGHT RECORDERS
CAMERA
CONTROL BOX
INSTRUMENT PANEL
CAMERA
4-26
AR769-2 DICIET RECORDER
Figure 4-7
STANDBY
MAGNETIC COMPASS
REAR VIEW PERISCOPE
FLIGHT RECORDER
' SWITCH
INSTRUMENT PANEL
CAMERA
DI CLEF
RECORDER
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SECTION IV
formation except heading will be recorded 1. Pre-engage synchronization.
for approximately 10 minutes after elec-
trical power is interrupted. The recorder
pitot static system remains available as an
alternate airspeed system when the re- 3. Pitch and turn wheel inputs.
corder is not installed.
Flight Recorder Switch
This toggle switch is located outboard of the
right console and has labeled positions ON
and OFF.
Pitot Pressure Selector Lever
This lever is located on the forward right
side of the cockpit wall. It is normally
safety-wired in the NORMAL position. In
the event of a malfunction of the normal
pitot static position system, the lever may
be moved to the ALT position. This fur-
nishes pitot static pressure from the flight
recorder system to the aircraft flight in-
struments and ejection seat speed sensor.
DICTET TAPE RECORDER
The Dictet Tape Recorder is located on the
left side of the canopy. It has two levers;
one labeled REWIND, RECORD and PLAY-
BACK and one labeled ON and OFF. It is
preset prior to flight and is activated by the
interphone switch. The tape is in motion
only when the interphone switch is used and
provides up to two hours of recording time.
AUTOPILOT SYSTEM
The autopilot portion of the AFCS relieves
the pilot from manual aircraft control and
provides a means for automatic navigation
when coupled to the output of the INS. The
autopilot functions are:
2. Attitude hold in roll and pitch.
4. Automatic pitch trim.
5. Heading hold.
6. Mach or KEAS hold.
7. Auto navigation.
The autopilot is optimized for basic mission
cruise speed and altitude but may be used at
other flight conditions.
There are no restrictions on use of the roll
autopilot. The autopilot authority is limited
to prevent severe maneuvers due to an auto-
pilot malfunction. The maximum pitch
authority below 50,000 feet is 1.3 up and
down elevon. Above o50,000 feet the maxi-
mum authority is 2.4 up and down elevon.
The maximum roll authority is 4 differen-
tial elevon. The autopilot signals are sum-
med with SAS signals and produce control
surface motion through the SAS electronics
and servos.
Do not use the autopilot when using
BUPD.
Autopilot control movement of the elevons
is not reflected in control stick motion.
Automatic pitch trim is operative when the
autopilot pitch channel is engaged. The
slow speed pitch trim motor operates to
correct for long period pitch trim changes
and there should be no pitch transient at
disengagement. Preengage synchronization
of autopilot pitch and roll trim operates
when the pitch or roll channels are disen-
gaged.
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Autopilot and Attitude Reference Selector Switch
This selector switch is located on the right
console outboard of the INS control panel.
The switch has three positions; FRS (for-
ward), OFF (center) and INS (aft). In the
FRS position directional signals from the
FRS compass and attitude signals from the
FRS pitch and roll gyros are supplied to both
the autopilot and the attitude indicator. In
the OFF position the autopilot can not be
engaged but pitch and roll signals from the
FRS are furnished the attitude indicator. In
the INS position the INS stable platform fur-
nishes pitch and roll signals to both the
autopilot and the attitude indicator and true
heading directional signals are furnished to
the autopilot. In the OFF and FRS positions
inverter power for autopilot, air data com-
puter, and TDI indicator is furnished by the
No. 1 inverter bus. In the INS position in-
verter power for these items is transferred
to the No. 3 inverter bus. This switching
provides the same phase of power for the
autopilot and the air data computer as that
provided for the FRS or INS.
Avoid excessive switching be-
tween FRS and INS positions
as the resulting power trans-
ients tend to degrade INS ac-
curacy.
AUTOPILOT CONTROLS AND INDICATORS
The autopilot controls and indicators are on
the SAS panel located on the right console.
The control stick is equipped with control
stick command and emergency disengage
switches. The circuit breakers are on the
right and center console circuit breaker
panels. Power is from the essential dc bus
and the No. 3 or No. 1 inverter.
Autopilot Pitch Engage Switch
A two-position pitch engage switch is lo-
cated on the inboard side of the autopilot
control panel. In the ON (fwd) position, the
pitch autopilot is engaged in the attitude
hold mode.
NOTE
At least one active SAS pitch
channel must be engaged &tad bank
angle must be less than 50 before
the pitch autopilot can be engaged.
The switch is held in the ON position by a
solenoid. The pitch channel may be disen-
gaged by placing the switch to the OFF posi-
tion, by using the disengage switch on the
control stick, or by turning the autopilot
selector switch OFF.
Autopilot Pitch Trim Synchronization Indicator
The pitch trim synchronization indicator
shows the amount of pitch signal existing
prior to engagement. An up or down dis-
placement of the needle indicates the di-
rection of the transient which will occur
when the pitch channel is engaged.
NOTE
The pitch trim synchronization
needle will normally be centered
within one needle width. Engage-
ment of the autopilot pitch channel
with more than one needle width
of misalignment is not recom-
mended.
Autopilot Pitch Control Wheel
A serrated pitch control wheel is located
just forward of the pitch engage switch.
The wheel is used to make pitch attitude
corrections when engaged in the attitude
hold mode. Forward rotation of the wheel
commands nose down and aft rotation com-
mands nose up. Pitch attitude changes 10
for 20o of wheel rotation.
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Autopilot Roll Engage Switch
A two-position roll engage switch is located
on the autopilot panel. In the ON (fwd)
position, the roll autopilot is engaged in
the attitude hold mode.
NOTE
At least one SAS roll channel and
one active SAS yaw channel must
be engaged before the roll autopilot
can be engaged. Bank angle must
be less than 50 .
The switch is held in the ON position by a
solenoid. Autopilot signals are supplied by
either the FRS or the INS, depending on the
position of the autopilot selector switch.
The roll channel may be disengaged by
placing the switch to the OFF position, by
using the disengage switch on the control
stick or by turning the autopilot selector
switch OFF.
Autopilot Roll Trim Synchronization Indicator
The roll trim synchronization indicator
shows whether or not a roll signal exists
prior to engagement. The needle always
deflects to the right and does not indicate
the direction of the transient which will oc-
cur at engagement.
NOTE
Roll engagement is not recom-
mended if the needle is deflected
to the side of the dial, indicating
a hardover signal.
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A-12
Autopilot Turn Control Wheel
SECTION IV
A serrated turn control wheel is located on
the autopilot panel. It allows the pilot to
make roll attitude corrections when engaged
in the attitude hold mode. Right rotation of
the wheel commands right roll and left ro-
tation commands left roll. Roll attitude
changes 1 for 10 of wheelorotation. The
pilot can command up to 50 of bank angle
in the attitude hold mode. Above 50� of
bank the roll autopilot automatically disen-
gages to prevent the steady pitch rate from
bottoming the pitch servos, as this would
eliminate pitch damping capability.
Mach/KEAS Hold Switch
A Mach/KEAS hold switch is located on the
inboard side of the autopilot panel. The
Mach or KEAS hold mode is engaged when
the switch is in the respective position,
provided the pitch autopilot is engaged. The
switch is held in by solenoid action. The
autopilot then controls the pitch attitude to
maintain the same Mach number or KEAS
that existed at the time of engagement.
When the Mach or KEAS hold is engaged,
the pitch attitude hold is discontinued and
the pitch control wheel setting should not
be changed. Mach hold reference signals
are supplied to the autopilot from the air
data computer.
Do not use the Mach/KEAS hold
mode when the TDI indication is
known or suspected to be in-
accurate.
Auto Nay Switch
An AUTO NAY switch is located between the
Mach/KEAS hold and heading hold switches.
The auto nay mode is engaged when the
switch is in the ON position provided the
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roll autopilot is engaged. The switch is
held on by solenoid action. Steering signals
are furnished by the INS and the autopilot
controls the aircraft to follow the selected
great circle course. If the heading hold
mode was previously engaged, it will be
disengaged when auto nay is selected. The
bank angle is limited to 30 in the auto nay
mode.
Heading Hold Switch
A heading hold switch is located on the out-
board side of the autopilot panel. The head-
ing hold mode is engaged when the switch is
in the ON position provided the roll auto-
pilot is engaged. The switch is held on by
solenoid action. Heading signals from
either the FRS compass or INS control the
roll axis of the aircraft to maintain the
heading existing at the time of engagement.
Heading hold may be engaged while in a
bank. The autopilot will roll the aircraft
to a wings level attitude and lock on the
heading at time of engagement. The head-
ing hold and auto nay switches are inter-
locked to permit only one to be engaged at
a time. The auto nay switch will be re-
leased when the heading hold switch is on.
NOTE
When in heading hold mode the drift
rate is similar to a free gyro rate
and will be approximately 8 per
hour increasing to 15 per hour in
polar areas.
Control Stick Command Switch (CSC)
A control stick command switch is located
on the right side of the control stick. While
the switch is depressed, both the roll and
pitch autopilots revert to the preengage
synchronization mode. This allows attitude
and heading to be changed without opposition
from the autopilot. When the switch is re-
leased, both the roll and pitch axes are en-
gaged in the attitude hold mode, regardless
of the mode that was engaged prior to de-
pressing the CSC switch.
Autopilot Emergency Disengage Switch
A trigger-type switch located on the forward
side of the control stick will disengage the
autopilot completely. The autopilot is not
reengaged when the switch is released.
NORMAL OPERATION
Engagement
The autopilot is placed in normal operation
as follows:
1. Check SAS engaged, recycle lights out.
2. Check pitch and roll trim preengage
synchronization indicators aligned.
3. Pitch and roll engage switches ON.
These switches may be engaged together
or separately as operation of the two is
completely independent.
NOTE
Bank angle must be less than 50�.
4. Mach/KEAS hold switch - OFF.
5. Heading hold - As desired.
If Auto Nay is required:
6. Autopilot selector switch - INS.
7. Auto Nay switch - ON.
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3.
Trim - As required.
WARNING
Autopilot pitch - ON.
4.
Do not operate manual roll or pitch
trim when the autopilot is engaged. 5.
Maintain stabilized KEAS or March
conditions for 60 seconds.
Disengagement
To change attitude or heading:
1. CSC switch - Depress.
After attitude and/or heading change:
2. CSC switch - Release.
3. Mach/KEAS hold switch - OFF.
4. Autopilot selector switch - As desired.
5. Heading hold or auto nay - As desired.
To disengage autopilot:
1. Autopilot disengage switch - Press.
or
2. Pitch and roll engage switches - OFF.
or
3. Autopilot selector switch - OFF.
Mach/KEAS Hold Engagement
Prior to engagement of Mach/KEAS hold
the pilot will accomplish the following:
1. Attain desired KEAS, altitude and Mach
number.
2. Throttle As required.
NOTE
Do not engage Mach/KEAS hold
during turns or other maneuvers
as undesirable transient will be
produced. Mach/KEAS hold may
however be left engaged during
turns if already on.
6. Mach/KEAS hold switch - ON as desired.
The pitch control wheel must not
be used during Mach/KEAS hold
operation to prevent rapid pitch
motion or disengagement.
To minimize altitude excursions during
turns:
7. Throttle - Gradually advance during
roll in.
8. Throttle - Gradually retard during roll
out.
Lf changing flight conditions, retrim when
power settings are changed more than 5%;
9. Mach hold - OFF.
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NAVIGATION EQUIPMENT
FLIGHT REFERENCE SYSTEM
The Flight Reference System and SR-3 com-
pass is a navigation system which supplies
information for indication and control of
aircraft heading and attitude. It can be
used independently of the Inertial Navigation
System. The FRS consists of a flight re-
ference platform, turn rate servo, induc-
tion compass transmitter, heading and atti-
tude couplers for the autopilot, control
panel, and the rotating compass cards of
the BDHI. Either a directional gyro (DG)
or magnetic slaved (MAG) mode can be se-
lected to provide directional reference to
all latitudes. In either mode:
Heading information is furnished -
(1) To the autopilot when the autopilot se-
lector switch is in the FRS position.
(2) To the BDHI compass card when the
autopilot selector switch is in the FRS
position.
Attitude information is furnished -
(1) To the autopilot when the autopilot se-
lector switch is in the FRS position.
(2) To the attitude indicator when the auto-
pilot selector switch is in the FRS posi-
tion.
Directional Gyro Operating Mode
When in the directional gyro mode of op-
eration, the FRS is free of magnetic influ-
ence and operates as a directional gyro,
indicating heading relative to an arbitrary
reference heading selected by the pilot. It
may be used at all latitudes, but is most
useful when the magnetic field is weak or
distorted or when navigating in the polar
regions. It is more reliable than the mag-
netic mode at latitudes near the magnetic
poles. When in the DG mode, with proper
hemisphere and latitude selection made on
the control panel, the gyro is made to pre-
cess to compensate for apparent gyro drift
due to earth rate at the selected latitude.
Magnetic Slaved Operating Mode
When operating in the magnetic slaved mode,
the FRS is basically a gyro stabilized com-
pass slaved to the induction compass trans-
mitter. This mode provides heading with-
out northerly turning error or oscillations.
It is less reliable than the DG mode at lati-
tudes near the magnetic poles as the MAG
mode is subject to severe magnetic dis-
tortion near those poles.
FRS COMPASS CONTROL PANELS
The COMPASS controls are located on the
right console, immediately forward of the
circuit breaker panel. The panel contains
a function selector switch, set heading knob,
latitude selector knob and indicator window,
synchronization indicator, malfunction in-
dicator, hemisphere selector switch, and
a take command button.
Take Command Button
A combination button and light on the con-
trol panel provides for transfer of control
of the FRS by depressing the button and ob-
serving the green light. It is not operative
on this installation.
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Function Selector Switch
The two position function selector switch
allows selection of either a magnetic head-
ing or a free gyro reference. The DG
(right) position selects directional gyro
mode; the MAO (left) position selects the
magnetic slaved mode.
Hemisphere Selector Switch
The Hemisphere Selector switch must be
set to correspond to the hemisphere in
which the aircraft is located. The left (S)
position is used when in southern latitudes.
The right (N) position is selected for
northern latitudes.
Latitude Selector Knob and Indicator
The latitude selector knob may be rotated
to select and display latitude in degrees and
tenths of degrees in the indicator window.
The knob is used only in the DG mode. The
latitude setting is used in the DG mode to
correct the directional gyro for the apparent
drift due to the earth's rotation. For ac-
curate operation of the FRS in the DG mode,
the latitude indicator must be set to coin-
cide with the actual latitude of the aircraft
at all times.
NOTE
The proper corrections will not be
made if the hemisphere selector
switch setting does not correspond
to the hemisphere in which the
aircraft is located.
Malfunction Indicator
A malfunction indicator is provided which
monitors the power supply and other prime
system functions. Any deviation of the
monitored functions from normal operation
will cause the indicator to display three
white triangles.
Heading Set Knob and Synchronization Indicator
The heading set knob provides a means to
fast slave or synchronize the rotating com-
pass card of the BDHI to the correct mag-
netic heading or desired gyro heading, de-
pending on the position of the function se-
lector switch. When in the MAO mode,
initial synchronization with the compass
transmitter heading is obtained by pushing
and holding the heading set knob until the
synchronization indicator becomes centered.
In the DG mode, the heading is set to the
desired initial indication by pushing and
turning the heading set knob. Turning the
heading set knob clockwise produces an in-
creasing heading, with the rate of change
being indicated by the deflection angle of
the synchronization indicator.
FRS OPERATION
1. Function selector switch - MAC or DG,
as desired.
2. Hemisphere selector switch - Set to
correspond with aircraft location in
Northern (N) or Southern (S) hemi-
sphere.
3. Latitude selector knob - Set to corre-
spond with existing latitude when DG
mode selected.
4. Heading set knob - Synchronize or
slave to heading desired.
5. Autopilot selector switch - FRS.
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SECTION IV A-12
FLIGHT REFERENCE SYSTEM (FRS)
COMPASS PANEL AND BDHI
DETAIL A
BEARING DISTANCE HEADING INDICATOR (BDH I
7063
Figure 4-9
DETAIL B
FLIGHT REFERENCE SYSTEM CONTROL PANEL
F200-65(b)
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Slaving
The normal slaving rate of the FRS is about
1-1/2o per minute. The gyro may be as
much as 180� from the proper heading when
the compass system is energized before
takeoff, and as much as 1-1/2 hours would
be required to slave to the correct heading
at normal slaving rates. Manual fast slav-
ing is provided by pushing and holding the
heading set knob depressed. This increases
the slaving rate to 720 per minute and will
correct a 180o error in 15 seconds.
If the compass is properly slaved before
takeoff, no in-flight manual fast slaving is
required unless free directional gyro op-
eration is selected. When operating in the
free gyro mode, the desired heading can be
established by using the heading set switch.
The roll autopilot must be disengaged
before attempting manual slaving
when the FRS is being used as a
heading reference.
FRS OPERATING CHARACTERISTICS
The SR-3 flight reference platform consists
of a single axis directional gyro which is
attitude stabilized by a two axis vertical
gyro. A compass transmitter is provided
which establishes the directional reference
while in level flight by detecting aircraft
heading with respect to the horizontal com-
ponent of the earth's magnetic field. When
the system is operated in the magnetic
mode, the directional gyro is slaved to the
compass transmitter at a rate of 1-1/2
degrees/minute. When operating in the di-
rectional gyro (DG) mode, the compass
transmitter signal is disabled and the head-
ing reference is established by the direc-
tional gyro operating as a free gyro (except
for earth's rate latitude correction). Elec-
trolytic gravity sensors are used in con-
junction with pitch and roll torquer motors
to erect the attitude gyro to the local ver-
tical. During periods of acceleration or
deceleration along the flight path, heading
and pitch attitude errors can be introduced
due to the following effects:
a. The pendulously supported compass
transmitter is displaced from the hori-
zontal plane and becomes sensitive to
the vertical component of the earth's
magnetic field. This results in an er-
roneous heading reference. The mag-
nitude of this error is a function of
aircraft heading, transmitter tilt angle
and the relative magnitude of the ver-
tical field component. This error is
introduced into the system at the nor-
mal slaving rate of 1-1/2 degrees/
minute.
b. The pitch erection sensor, which is
acceleration sensitive, provides an
output signal to the pitch torquer
causing it to precess the attitude gyro
to a false vertical at a normal rate of
4 to 5 degrees/minute.
In order to minimize the above deficiencies,
an electrolytic fore or aft acceleration cut-
out sensor (similar to the pitch erection
sensor) is provided on the pitch gimbal of
the attitude gyro. This sensor disables the
pitch erection and slaving circuits when a
threshold setting of .065 g along its sen-
sitive axis is exceeded. However, operat-
ing as a free vertical gyro, it is subject to
an apparent drift from the vertical due to
the effect of the earth's profile and earth's
rotation. These effects, coupled with the
gyro free drift rate of 15 degrees/hr, re-
sults in a total drift from the vertical of
about 1 degree/min. This displacement
of the attitude gyro causes a gravity com-
ponent to appear along the sensitive axis
which acts as a bias to the horizontal ac-
celeration signal (.065 g) which initiates
slaving and pitch erection cutout. When the
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bias signal acts in opposition to the sensed
acceleration signal the effective value may
drop below the .065 g threshold, thereby
restoring pitch erection and slaving while
the aircraft is still accelerating. The atti-
tude gyro will then erect to a false vertical
at the normal erection rate and the compass
transmitter will precess the directional
gyro to a false heading as determined by the
transmitter tilt angle. When the attitude
gyro drift exceeds 3-1/2 degrees, and the
bias signal acts to aid the sensed accele-
ration signal; the system will maintain the
cutout condition for an indefinite period
after aircraft acceleration has ceased. In
order to prevent this condition, the system
is designed to limit pitch erection cutout to
a maximum period of 4 minutes independent
of acceleration.
In operational use the SR-3 system performs
in the manner described above during per-
iods of prolonged acceleration such as dur-
ing acceleration-climb to supersonic cruise
speed after takeoff and after refueling.
During climbout, pitch attitude and heading
errors increase to about 6 degrees and 8
degrees respectively. These errors are
eliminated at the normal rates when air-
craft acceleration ceases. The heading
error can be washed out very rapidly by
pushing and holding the heading set knob on
the FRS control panel until the synchron-
ization indicator becomes centered. During
aircraft turns in excess of 5 degrees/min
the system operates as designed to cutout
roll erection and slaving. Whenever a turn
is initiated immediately following cam.bout,
the accumulated climbout heading error will
be increased and be maintained throughout
the turn.
INERTIAL NAVIGATION SYSTEM (INS)
The inertial navigation system is self-
contained and operates in all modes with-
out the use of electromagnetic radiation or
external references. The system consists
of a gyro-stabilized platform, platform
electronics, coupler and power supply, re-
peater and converter assembly, digital
computer and computer power supply, con-
trol panels, and distance-to-go, ground-
speed, and a direction indicator.
In operation the system displays present
position, ground speed and the direction
and distance to go to any of 42 preselected
positions as continuous readouts. When
operated in autopilot AUTO NAY, and INS
STORED AUTO mode, the aircraft will be
steered automatically to each point in the
flight plan sequentially, with no pilot action
required. If the flight plan is being flown
in sequence in the STORED AUTO mode,
the destination select light will illuminate
if the destination displayed on the destina-
tion select panel does not agree with the
destination towards which the aircraft is
flying. This light is extinguished when the
pilot sets the selector panel to the number
of the stored destination being approached.
The destination select panel provides se-
lection of destination numbered 0 through
41. The first 27 preselected positions are
assigned to preplarmed mission destinations,
fix points, targets, rendezvous points, or
other points occurring sequentially during
the mission. The computer computes and
stores the great-circle courses between
each pair of these numerical points, and
the aircraft will adhere to these great cir-
cle courses. Turns from one course to
another will be made with bank angle op-
timized (with a maximum bank of 30 de-
grees) for the groundspeed and heading
change required. The number 2 pointer of
the BDHI will point toward the optimum
path to follow to place the aircraft on the
next course. If the pilot switches to a sub-
sequent destination in STORED MANUAL
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before completing the route segment he is
on, the turn will be made in accordance with
computer program directions.
Positions 27 to 41 provide ADF type steer-
ing for courses to these points and not
meant to be used in the STORED AUTO
mode. These positions are available for
alternate destinations or may be used to
employ an alternate flight path to a position
included in the first 27. A sufficient num-
ber of alternate destinations is available to
provide adequate coverage throughout the
mission. Duplication of any of the first 27
positions in this group provides a steering
indication on the BDHI number 2 pointer re-
sembling that of ADF navigation, i. e., the
pointer points directly to the next destina-
tion (within a 45 degrees needle deflection).
The basic reference of the inertial naviga-
tion system is provided by three single-axis
accelerometers mounted at right angles to
each other on a gyro-stabilized platform.
The platform employs three floated inte-
grating gyros, also mounted at right angles.
The platform is initially aligned with a co-
ordinate reference frame, represented by
a plane tangent to the surface of the earth
and oriented to any convenient azimuth at
the point origin. The platform stable ele-
ment is isolated from the airframe through
a system of three gimbals which provide
360 degrees freedom of rotation in yaw and
roll, and pitch angles of + 60 degrees. All
platform outputs are changed to digital form
before entering the computer. In normal
operation the platform als,o'provides atti-
tude outputs in analog form through resol-
vers and synchros to the autopilot, and the
attitude indicator. Conversion of present
position to latitude and longitude readout is
accomplished continuously by the digital
computer when in operational mode. Cool-
ing air, necessary to the system, is sup-
plied by the aircraft airconditioning and
pressurization system. A self-contained
heating system is incorporated in the plat-
form to ensure that gyros and precision
sensing components are maintained at tem-
perature within an optimum operating range.
The system is powered by the No. 3 inverter,
the LH generator, and the monitored dc
bus.
NOTE
Accuracy of INS information will
be slightly degraded if pressure
altitude data supplied by the air
data computer is lost or is in-
accurate.
The INS is controlled from two control
panels, the navigation panel and the destin-
ation select panel. (See figure 4-10).
NAVIGATION PANEL
The navigation control panel, located on
the right console, consists of a DEST/FIX
selector switch, STORE pushbutton, MODE
selector switch, FIX ADJ knob, two sets of
geographic coordinate digital readout win-
dows, labeled PRESENT POSITION and
DESTINATION/FIX POSITION, a VARI-
ABLE INPUT indicator labeled LAT and
LONG, with thumbwheels for manual inser-
tion of geographic coordinates and a switch
for selection of N or S latitude. The con-
trols and indicators are as follows:
Mode Selector Switch
The mode switch is a rotary selector switch
with five positions, labeled as follows: OFF,
RST, ALGN, NAV, and FRS.
NOTE
During flight the MODE switch must
not be switched to any position other
than NAY or FRS, otherwise the INS
will be deactivated and will not func-
tion until the switch is moved through
OFF, RST, and ALGN positions in
conjunction with the ground operating
equipment and normal INS preflight
procedure.
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A-12
INS PANEL AND INDICATORS
NAVIGATION CONTROL PANEL
(RIGHT CONSOLE)
7063
BEARING DISTANCE HEADING INDICATOR (BDH I ) DISTANCE TO GO/GROUND SPEED INDICATOR
Figure 4-10
DESTINATION SELECT PANEL
F2.00-34(f)
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Do not move the MODE selector
switch from the OFF position in
flight if the INS has not been cycled
from OFF to the NAV mode prior to
flight. The INS system will be
damaged.
RST Mode
The RST (reset) mode is used only on the
ground during INS preflight when the plat-
form has reached operating temperature.
it permits the ground operating equipment
(GOE) operator to check correct power
switchover from ground to aircraft power,
start the gyro spin motors, and make the
computer ready for use.
ALGN Mode
The INS must be completely warmed up,
stabilized, and aligned to a coordinate re-
ference frame before it can be operated.
This is necessary to minimize the drift of
the stable reference platform once it is
aligned to the coordinate reference frame.
The complete warmup and alignment pro-
cedure at normal ambient conditions takes
about 1-1/2 hours. During this period the
destination loading operation is accom-
plished, normally by use of a punched tape.
However, the coordinates of the present
location and 42 destinations or targets may
be set in manually by the VARIABLE INPUT
thumbwheels and N-S selector and entered
into the computer memory by pushing the
STORE pushbutton for each position. After
a period of gyro stabilization, the platform
is torqued to the coordinate reference
frame and the gyros are drift-trimmed.
The two transverse horizontal acceler-
ometers are used to sense the local vertical
and their outputs are used in the servo
loops that torque the platform and measure
the amount of gyro drift. The presence of
output signals from each accelerometer in-
dicates that the platform is not level in that
axis. While level aignment of the platform
is being accomplished automatically, plat-
form azimuth is aligned with a selected re-
ference which is transferred to the plat-
form by the ground operator. The platform
is drift-trimmed at the reference points
thus established, and the drift will be re-
duced to certain preestablished rates be-
fore the system can be operated. There is
a detent between NAV and ALGN positions
and the MODE switch cannot be moved
either way between these two positions un-
less it is depressed.
NAV Mode
Switching to the NAV mode permits the
GOE to be disconnected, and places the
platform in the operational mode. The
gyros are essentially memory devices that
memorize the coordinate frame established.
The system operates using these memoriz-
ed coordinates to perform the navigation
problem, and the accelerometers measure
translations of the platform caused by
movement of the aircraft. The acceler-
ometer outputs are integrated once to pro-
vide velocity on each axis, and a second
time to establish their displacement from
the point of origin. These displacements
(distances flown) are translated into geo-
graphical position coordinates by the com-
puter. In addition to indicating position
coordinates to the pilot, this position is
also used to torque the platform to the lo-
cal vertical and azimuth as the aircraft
changes position. The coordinate frame
thus rotates about the earth to retain its
orientation on a plane tangent to the sur-
face of the earth at the position of the air-
craft.
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FRS Mode
The flight reference system is the primary
backup for the INS. Normally, the INS is
operated with the switch in the NAV posi-
tion, but the pilot may switch to the FRS
position at any time to check FRS operation.
When the switch is in the NAV mode, the
BDHI rotating compass card indicates INS
true heading; when in the FRS mode, the
card indicates magnetic heading. When the
switch is moved from the NAV to the FRS
mode, the INS system continues to operate
normally.
WARNING I
If the INS should fail, the MODE
switch should be moved to the
FRS mode without delay in order
to retain a heading indication on
the BDHI display.
DEST/FIX Switch
The DEST/FIX (destination or fix) switch is
a five-position rotary selector switch with
positions as follows:
STORED
AUTO, FIX, MAN
VARIABLE
FIX, DEST
STORED AUTO. The INS will automatically
sequence consecutively through the 42 pre-
stored destinations as each is reached when
the switch is in the STORED AUTO position.
STORED FIX. To use a prestored destin-
ation as a fix point, the switch is set to the
STORED FIX position, the destination se-
lect panel is set to the desired destination
number, and the STORE pushbutton is de-
pressed when the fix point crosses the hor-
izontal line on the periscope screen.
STORED MAN. To select any of the 42 pre-
stored coordinate positions as a destination,
out of the automatic consecutive sequence,
the switch is set to the STORED MAN
(manual) position, the destination select
panel is set to the desired destination
number, and the STORE pushbutton is de-
pressed.
VARIABLE FIX. To use a variable (un-
stored) fix point as a point of reference,
the switch is set to the VARIABLE FIX
position, the VARIABLE INPUT thumb-
wheels are set to the fixpoint coordinates,
and the STORE pushbutton is depressed
when the fix point crosses the horizontal
line on the periscope screen.
VARIABLE DEST. To select a variable
(unstored) destination, the switch is set to
the VARIABLE DEST (destination) position,
the VARIABLE INPUT thumbwheels and
N-S selector are set to the desired coordi-
nates, and the STORE pushbutton is de-
pressed.
FIX ADJ Knob
The fix-adjust knob, labeled FIX ADJ, con-
trols a flight cursor on the periscope and
is used to update the INS by means of visual
fixes on known coordinate points. It is not
necessary to fly directly over the fix point
to obtain useful data. Viewing the fix point
on the screen, the pilot positions the cursor
with the FIX ADJ knob to coincide with the
fix point as it crosses the horizontal re-
ference line on the display. (Refer to dis-
cussion of fix-taking for further information.)
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SECTION IV-
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STORE Pushbutton
The STORE pushbutton is used to store in
the computer memory either selected des-
tination information or position information
which has been selected by the VARIABLE
INPUT thumbwheels and N-S selector. It
also initiates the computations required to
navigate to the coordinates selected.
Do not push this button unless a
course change or fix is desired.
NOTE
The DEST/FIX pushbutton on the
destination select panel is iden-
tical in function to the STORE
button on the navigation panel.
They may be used interchangeably.
N-S Hemisphere Selector Switch
The N-S selector switch may be placed in
either N or S, depending in which hemi-
sphere the desired destination or fix is lo-
cated. This selector is only used in con-
junction with the variable input thumb
wheels to manually insert a destination or
fix point in flight.
VARIABLE INPUT Indicator
The VARIABLE INPUT indicator has thumb-
wheels that are used to manually insert any
desired reference coordinates into the sys-
tem, thus giving the pilot added flexibility
of operation in flight. (It is good practice
to put the DEST/FIX switch in the VARI-
ABLE DEST or VARIABLE FIX position
prior to setting the coordinates in the indi-
cator.) To insert variable destination co-
ordinates into the system, select VARIABLE
DEST on the DEST/FIX switch, then insert
the desired destination coordinates with the
VARIABLE INPUT thumbwheels; select de-
sired hemisphere with the N-S selector and
depress the STORE pushbutton. The DES-
INTATION/FIX POSITION indiCator will
read out the new coordinates immediately
after the STORE button is depressed, and
the INS will navigate the aircraft to the new
destination using ADF type steering. Vari-
able update fix coordinates are inserted in
the computer in the same way as a destin-
ation, except that VARIABLE FIX is se-
lected on the DEST/FIX switch.
PRESENT POSITION Indicator
The PRESENT POSITION indicator is set at
the geographical coordinates of the flight
origin site prior to takeoff. In flight it
continuously indicates the coordinates of
the aircraft position as computed by the
INS.
DESTINATION/FIX POSITION INDICATOR
The DESTINATION/FIX POSITION indicator
normally displays the latitude and longitude
coordinates of the destination to which the
INS is navigating. This display may be the
coordinates of any selected destination from
the 42 prestored positions, or the coordi-
nates of any selected variable destination.
This coordinate display normally changes
at such times as the computer calculates
a new course to a newly selected destina-
tion. For STORED MANUAL or VARI-
ABLE DEST modes, this change will occur
upon depressing the DEST FIX or the
STORE pushbutton. For sequential or out
of sequence destination selections in
STORED AUTO mode, the destination co-
ordinate display will change coincident with
roll out to the new destination course. The
minutes counter portion of the latitude dis-
play may also change whenever a fix is
taken. When either a STORED FIX or VAR-
IABLE fix is taken, the calculated cor-
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SECTION IV
A-12
rection (in nautical miles) is displayed on
the latitude minutes display, without chang-
ing longitude, or the degrees portion of lati-
tude on the DESTINATION/FIX POSITION
indicator. The portion of the latitude dis-
play used for the fix distance indication is
blocked off in white on the indicator (see
figure 4-10). The calculated fix correction
is displayed up to a maximum value of 59
nautical miles whether position is updated
or whether the fix is rejected. The calcu-
lated fix correction will continue to be dis-
played until another fix is taken, or until a
new destination is selected and displayed.
When a new destination is selected, the lati-
tude minutes counters will revert to a dis-
play of destination latitude until such time
as another fix is taken.
DESTINATION SELECT PANEL
The destination select panel, labeled NAV,
is located on the instrument panel. The
panel has a two-place digital counter, con-
trolled by thumbwheels, and a self-illumi-
nated pushbutton switch which read out
DEST FIX when lighted. The number of a
stored destination or fix (0 through 41) may
be set on the counter manually and inserted
into the INS computer by depressing either
the DEST FIX or the STORE pushbutton.
NOTE
Positions 42 through 49 can be dis-
played, but are inoperative.
The DEST FIX pushbutton illuminates when
the destination number on the panel and the
destination approached by the aircraft are
not the same. When they are again the
same (thumbwheels must be rotated), the
light will go out. In all modes the light will
come on when pilot action is required.
When the DEST/FIX switch is placed in
either STORED or VARIABLE FIX, the light
will come on. When the STORE pushbutton
is depressed the light will go out. In any
mode in which a new destination is selected
by depressing the STORE pushbutton, the
light will go out when the system accepts
the new destination selection. When a des-
tination inside the aircraft's minimum turn
radius is selected in the STORED MAN or
VARIABLE DEST mode, the DEST FIX light
will blink on and off. When the aircraft's
location falls outside the minimum radius
path, the blinking DEST FIX light will ex-
tinguish and the destination will be accepted.
In the STORED MAN mode, the light will
also come on if a destination is passed over
by 15 miles without selecting a new des-
tination. (DTG 15 NM or greater and in-
creasing).
DISTANCE-TO-GO AND GROUNDSPEED
INDICATOR
A distance-to-go and groundspeed indicator
Is installed on the instrument panel. Digital
indicators display the distance between the
aircraft position and the destination, and the
groundspeed, in units of 1 nautical mile and
knots, respectively. When a new destination
Is selected either automatically or manually
the indicator will change to show the new
distance-to-go. The distance-to-go indica-
tion will decrease toward zero while ap-
proaching the destination, then increase
after passing the destination if flight is con-
tinued on the same course. Distance-to-go
will not read zero at destination if the com-
puted cross-course distance is greater than
1/2 nautical mile, since readout resolution
is to the nearest nautical mile.
BEARING, DISTANCE, HEADING INDICATOR
(BDHI)
The INS computes true heading and steering
information and this information can be dis-
played by the BDHI installed on the instru-
ment panel. The rotating compass card of
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A-12 SECTION IV
INS STEERING CHARACTERISTICS
DISTANCE TO GO-NAUTICAL MILES
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
4----1--+-
1200
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D.T.G.
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NEW COURSE
GROUND
CHANGE
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SPEED AND COURSE
SCHEDULE
DESTINATION
A-
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Z7-
NEAR.PATH
STEERING
1
VARIABLE
1
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BANK ANGLES
1
30� OR
LESS
45�
30� CONSTANT
FAR PATH
STEERING
BANK
ANGLE
100�
/
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D.T.G.
i
900
11
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0
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01111111111 14/.1PP:
30�
200
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100
_
100 200 300 400 500 600 700 800 900 1000 1100 1200 1300. 1400 1500 1600 1700 1800 1900 2000 2100
GROUND SPEED ON ENTRY INTO TURN-US.
1
1
I
1
1
1
0.52
1.04
1.55
2.07
2.58
3.1
APPROX. MACH NO.-(BASED ON-56.5�C. F. A. T. DAY)
Figure 4-11
10-24-66
F200-16(d)
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SECTION IV
A-12
the BDHI receives the true heading signals
as long as the MODE switch on the INS
NAVIGATION control panel is in the NAV
position. When the MODE switch is in the
FRS position the compass card is driven by
the FRS signals, although the INS system
still generates true heading. Pointer 1 of
the BDHI is driven by the ADF or TACAN
as selected by the No. 1 needle selector
switch. Pointer 2 is driven by the steering
signal of the INS when the MODE switch on
the NAVIGATION control panel is in the
NAV or FRS position. Pointer 2 points to
the direction of the great circle course or
in ADF steering mode will point to destin-
ations which are within 45 degrees of the
aircraft heading (or indicate direction to
turn if angular difference is greater than 45
degrees).
NOTE
. The aircraft will automatically fly
the course computed by the INS
and selected by the pilot only if the
autopilot is in the AUTO NAV mode.
A 45-degree turn indication on the
BDHI pointer 2 commands a 30
degree bank angle to be made by
the autopilot. The bank angle
command is proportionately smaller
when smaller turn angles are in-
dicated on the BDHI.
COURSE SELECTION
In the STORED AUTO mode, the INS is
capable of providing steering information
to any selected destination when the path
from source to destination is greater than
30 nautical miles but less than 21,500 nau-
tical miles (from 1/2 degree to 179 degrees
of great circle arc). In the STORED MAN
mode, the above restrictions exist only for
destinations numbered 00 through 26. The
sequence in which courses are provided de-
pends upon the position of the DEST/FIX
switch on the navigation control panel. In
STORED AUTO position, course directions
will be provided to stored destinations auto-
matically in their numerical sequence;
however, an out of sequence deviation can
be made in STORED AUTO by selecting
the desired out of sequence destination
number on the destination select panel and
depressing either the DEST FIX or STORE
pushbutton. After the out of sequence dev-
iation, other destinations will then continue
to be automatically selected in numerical
sequence. In the STORED MAN or VARI-
ABLE DEST positions, steering directions
to individual destinations are supplied after
each destination is selected by depressing
either the DEST FIX or STORE pushbutton.
For STORED AUTO or STORED MAN modes,
the steering information provided by the
computer is a great circle flight path only
if the destination selected is one of the first
27 sets of stored coordinates (00 through
26). ADF type steering will be commanded
for STORED destination selections numbered
27 or greater and for all VARIABLE DEST
mode selections. In STORED MAN mode,
the computed course starting point is deter-
mined as follows:
a. The position of the current desti-
nation is selected by the computer
as the starting point for the new
course if the aircraft computed
position is within 100 miles of
this point when the STORE button
is depressed.
b. The computed position of the air-
craft is selected by the computer
as the starting point for the new
course if the distance to go is
more than 100 miles from the
current destination.
After a course has been selected and cal-
culated and either great circle or ADF
type steering provided to navigate toward
the course destination point, the INS will
continue to navigate to that point regard-
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A-12
SECTION IV
INS DESTINATION REJECT PATTERN
TURN RADIUS (NM)
110
100
90
80
70
60
50
40
30
20
10
00
TURN RADIUS VS TRUE AIR SPEED
300 BANK ANGLE
DESTINATION
ACCEPTANCE
MINIMUM RADIUS
I
DESTINATION V
RADIUS
REJECTED
E'
2 4 6 8 10 12 14 16 18 20
TRUE AIR SPEED (KNOTS X 100)
DESTINATION
REJECTED
DISTANCE
TO GO
NOTE
The system will not accept a new
destination at any time it is
within the minimum turn radius
circles which move along with the
aircraft. The radius is a functional
of aircraft velocity for a 30� bank
angle. R x 10-5 V2
Where R is the turn radius in
nautical miles and V is velocity in
knots.
� DESTINATION
ACCEPTANCE
MINIMUM RADIUS
Figure 4-12
FLIGHT PATH
10-25-66
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SECTION IV
A-12
less of any change of position of the DEST/
FIX switch until a new destination is se-
lected by either automatic sequencing in the
STORED AUTO position or by depressing
the STORE pushbutton in the STORED MAN
or VARIABLE DEST positions. If a desti-
nation selection is made in which the new
destination is aft of the present course di-
rection by an angle greater than 135 , the
initial steering direction is indeterminant
and the aircraft may roll out either right or
left in turning around to the new course.
Fixed-Path Flight Plan
A preselected-path flight plan will be flown
in AUTO mode. Consecutive destinations
00 through 41 will be selected automatically.
The point-to-point paths will be segments of
great-circle arcs for destinations 01 through
26, and direct for destinations 27 through 41.
The use of STORED AUTO mode results in
smooth entry turns at required bank angle
up to a maximum of 30 degrees to the next
course. Turns will be initiated before
reaching the destination and the turn point
will depend on aircraft groundspeed and the
degree of course change required.
Deviation from Fixed-Path Flight Plan Using
Stored Destinations
Stored destinations may be selected man-
ually in any arbitrary sequence, and a des-
tination can be selected any number of times
during a mission. Any partial sequence of
the stored destination fixed-path plan can be
used by manually selecting the first destin-
ation of the sequence, then switching to
STORED AUTO mode until the desired se-
quence is accomplished. Then, manual se-
lection of a new stored destination causes a
new course to be computed as described
above.
NOTE
In the STORED MANUAL mode, if
the aircraft flys over the destin-
ation in great circle steering with-
out selecting a new destination,
the DEST/FLX light comes on and
the vehicle will alternate between
right and left steering signals.
The DEST/FIX light operates
similarly in ADF steering; how-
ever, the aircraft will fly in
circles, always coming back
over the selected destination.
Deviation from Fixed-Path Flight Plan Using
Stored Auto
One or more destinations can be skipped by
selecting the destinations desired on the di-
gital counters of the DESTINATION SELECT
PANEL and depressing the STORE push-
button with the DEST/FLX switch in the
STORED AUTO position. The INS will com-
plete the track in progress when the STORE
pushbutton is depressed but the next automatic
sequence will select the course to the de-
sired destination.
In the STORED AUTO mode, the destination
select light is extinguished when the number
on the destination select panel agrees with
the stored destination which is presently
selected. The stored destination which ex-
tinguishes the light will be the same as the
stored destination toward which the aircraft
is flying except when selecting a destination
out of sequence in the STORED AUTO mode.
Example: The aircraft is flying towards
destination 02 in the STORED AUTO mode
and 02 is selected on the destination select
panel. The destination select light is ex-
tinguished. The pilot decides to skip des-
tination 03 and fly from destination 02 to 04.
He selects 04 on the panel and depresses
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SECTION IV
A-12
the store button. The light will now be ex-
tinguished only on destination 04 even
though he is still flying towards 02. This
Indicates to the pilot that 04 has been ac-
cepted as the next destination.
Use of the VARIABLE INPUT Indicator For Unstored
Destinations
Use of destination coordinates set on the
VARIABLE INPUT indicator and N-S se-
lector requires that the DEST/FIX switch
be set to the VARIABLE DEST position.
ADF-type steering to the point selected is
provided when the STORE pushbutton is de-
pressed. The initial ADF-type steering
heading is based on computed present posi-
tion. Coordinates of stored destinations
can be duplicated.
LIMITATIONS OF DESTINATION SELECTION
Maximum Path Length
The maximum great-circle arc between
source and destination is 179 degrees to per-
mit definition of direction. This consti-
tutes a distance of approximately 17,800
nautical miles from source to destination.
Minimum Path Length
In the STORED AUTO mode, a course cannot
be selected when the distance from the start
point (either a stored destination or the air-
craft's present position) to the next desti-
nation is less than 30 nautical miles. The
computer will ignore any attempt to select
such a destination. In the STORED MAN
mode the 30 mile restriction exists only for
destinations numbered 00 through 26. How-
ever, all destination selections are restricted
by comparing the desired destination's re-
lative location with the aircraft's minimum
turn radius capability. (The minimum turn
radius is computed as a function of ground
speed.) The destination is accepted if it is
outside the minimum turn radius path. If
the desired destination is inside the mini-
mum turn radius path, the DEST FIX light
on the DESTINATION SELECT PANEL will
blink on and off, indicating that the computer
has acknowledged the destination. The air-
craft will continue on its same course until
its location falls outside the minimum turn
radius path. At such time, the DEST FIX
light will extinguish and the destination will
be accepted. (See figure 4-12.)
Minimum Distance Between Destinations
In the STORED AUTO mode, a course can-
not be selected when the distance from the
start point (either a stored destination or
the aircraft's present position) to the next
destination is less than 30 nautical miles.
In the STORED MAN mode the 30 mile re-
striction exists only for destinations num-
bered 00 through 26.
FIX TAKING
Since all rotating gyros are subject to some
drift, alignment of the coordinate reference
frame established by the gyro platform
tends to depart from the true coordinate
frame after a period of time. This intro-
duces errors in position and azimuth which
increase with time. (See figure,4-13.) The
indicated position can be updated by taking
visual fixes when the coordinates are known.
These fixes are taken by use of the peri-
scope and are inserted into the INS as fol-
lows:
1.
2.
Either select the desired prestored des-
tination on the destination select panel
or set the coordinates of the fix point
in the VARIABLE INPUT indicator and
N-S selector.
Turn the DEST/FIX switch to the ap-
propriate STORED or VARIABLE FIX
position. (Use STORED FIX position
if the fix to be made is at a prestored
coordinate point.)
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A-12
INS POSITION AND AZIMUTH ERROR
0
uJ
ce
0
0
0-
AZIMUTH MISALIGNMENT - ARC SECONDS
14
12
10
8
6
4
2
0
800
600
400
200
0
200
400
600
800
,
I
II
..
,..7-----
,�.
/
POSITION
ERROR