ARDF IN SOUTHEAST ASIA

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80R01720R001300030001-0
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 21
• Document Creation Date: December 20, 2016
• Document Release Date: August 15, 2005
• Sequence Number: 1
• Publication Date: May 25, 1973
• Content Type: MEMO

WASHINGTON, D.C. 20301
SI-TSU-71,1.79/DC-7B
MEMORANDUM FOR THE ASSISTANT SECRETARY OF DEFENSE (INTELLIGENCE)
SUBJECT: ARDF in Southeast Asia
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1. In response to your request, DIA has reviewed the current ARDF
situation in Southeast Asia. Although focused on the deficiency in
desired coverage of RVN Military Region I targets, the total SEA ARDF
picture was examined. Specifically, we reviewed the current fix
requirements, the current dispos:tt.i.on. of enemy forces, disposition of
US and RVNAF ARDF assets, problem areas and possible actions to improve
the situation.
2. Our study draws heavily from the views of Commander USSAG and NSA,
since they are closely associated with the day-to-day ARDF effort.
Our analysis leads to the conclusion that there has been a severe
decline in the fix ;ate and target coverage, compared to that of a year
ago. This decline is not surprising, however, when consideration is
given to:
a. Changing US force deployment - During the heat of the war the
US had approximately 120 ARDF aircraft, flying about 450 sorties per
week. We now have only 28 US (22 USAF EC-0's and 6 US Army U--21's)
and 36 (33 EC-47's and 3 U-6's) RVNAF aircraft generating approximately
200 sorties per week.
b. Changing enemy situation -- Comparison of the enemy AAA/SAM
capability in Northern RVN MR-1 and the Southern Lao Panhandle area
reveals that a significant improvement in their air defense capability
has been made since the cease fire, e.g., establishment of SAID sites at
Khe Sanh, more AAA, etc. This improved enemy capability is the result
of the decline in US involvement and air operations against the AAA/SAM
sites.
3. Given these factors there are only two courses of action which might
afford improvement in the situation:
a. First, improved management and mission allocations from current
resources. Our analysis indicates that no improvement in coverage of
11R-1 would be. gained from outside involvement in the USSAG Commander's
DIA review(s) completed.
NSA review completed
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 allocation of weekly ARDF missions. The governing factor for decreased
coverage of this area is not management, it is the vastly increased
AAA/SLA2l]' threat.
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(1) With the threat in mind, the Commander USSAG allocates
sorties on the recommendations of the J-2 and ARDF Coordination. Center
(ACC) at Allocations of US effort are projected on avail-
ability o- aircra-t: and priorities are based on requests
activities in SEA; specifically the US Ambassador to Laos,
USSAG, command priorities and ongoing tactical activity, as well as
national needs.
(2) Similarly, the RVN Directorate General of Technical
Services (DGTS) allocates sorties based on the current situation and
high interest areas of the GVN, and toward the fulfillment of national
and tactical requirements. Acknowledging a reduced DGTS frag rate, due
to lack of trained crews and manning shortages, three other factors
impact upon R.VNAF ability to effectively cover. MR-1: weather, maintenance,
and, most significantly, the enemy AAA/SAM threat.
(3) The service ceiling, speed, and maneuverability of the
EC-47 platform make it imprudent to expose these sensitive and limited
resdurces'to such high risks. Unfortunately, these high threat areas
are the very areas of highest intelligence interest. Rebasing of aircraft
in this instance offers no solution. to the problem.
(4) It should be noted that no US EC--4i7 aircraft have been
fragged into this area since the Easter offensive of last year. Coverage
had been provided. by Army U-21 assets, which were more maneuverable in the
hostile environment then extant, prior to their redeployment from R.VN.
The increased threat would now preclude using U-21?s.
b. Second, development of an improved ARDF capability on an aircraft
which has a higher altitude and flight endurance capability than either
the EC-?47 or U-21. The JCS studied the possibility of developing an
improved ARDDF capability earlier this year. It was determined that the
C-130 aircraft was the most likely airframe to be modified. However, it
was concluded by the Joint Chiefs of Sta.ff,on 5 March 1973, that the
Air Force did not have C-130 aircraft available to modify for this
purpose and, that the cost of 9.6 to 12.6 million for modification and
lead time of five to six months before deployment was prohibitive.
P E uiI:
US Ambassador to Cambodia, DAO/DoD SPECREP Saigon, J-2
'4. Recognizing that the Commander USSAG, with advice from appropriate activities,
is managing available resources in accordance with the dictates of the
current situation, the lack of an improved ARDF capability, and the threat,
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Brigadier General Jacobson, J-2, USSAG in a recent message to DIA,
summed the situation as follows: "USSAG believes that the potential intel-
ligence return'does not warrant the risk of possible loss of life, aircraft
and sensitive information. Hence, no US ARDF missions are flown in
Northern MR-1 nor any other AAA operating area. Similarly, neither does
the RVNAF commit their limited assets to high risk areas. The level of
ARDF coverage to which the intelligence community has been accustomed is
steadily diminishing, and in view of the situation there does not appear
to be any way to reverse this trend."
5. I concur with General Jacobson's assessment and, operating within the
present fiscal and political constraints on US involvement in SEA, it
appears unlikely that additional or alternate US ' airborne platforms/
equipment can be made available to augment the present effort. Therefore,
accepting that the Commander USSAG is well aware of our requirements,
along with those of other US activities in SEA, I recommend that we
continue to rely on his judgement for.the utilization of ARDF assets in
attempting to satisfy all requests placed on him.
1 Enclosure V.
Digcussibn Concerning ARDF Vice Admirv-Ji !
in.-SEA (TSU) Wiicvwv~a
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Discussion Concerning ARDF in SEA
1. In reviewing the problem as presented by Colonel Bush, OASD(I),
the ARDF problem in RVN Military Region I could not be addressed in
isolation. The problem necessitated review of total effort since US
assets are based in Thailand and are required to cover areas other
than MR--I, as well. as looking at the GVN effort. The following
questions and discussion items are relevant to the ARDF situation
in SEA.
2. What are the desired fix requirements for SEA?
a. This question is difficult to quantify since it is desirable
to have some units located daily, some two or three times per week,
some weekly and others less often. Additionally, fix requirements
change as units alter their activity and maneuver into tactical read-
iness conditions and position. In recognition of this type situation
the WASAG Working Group "C", chaired by Mr. Carver, stated in a report
to Dr. Kissinger in November 1972:
(1) Tho ability to accurately detect military unit movements
in South Vietnam, Laos and Cambodia. will continue to depend on the use
of specifically configured EC--47 and U-21 aircraft. Because of the
short range of these direction finding and collection aircraft, they
must be operated from nearby Udorn, For the immediately 25X1
foreseeable future, about five missions in Laos, one in Cambodia, and
ten in RVN (to cover GVN shortfalls, especially in MR's 1 and 2) wii.l.l
be needed daily to cover these targets. This same geographic coverage,
but at a higher mission rate, has been conducted throughout the war.
The nature of the individual mission will have to determine which
aircraft type is to be employed.
(2) The South Vietnamese, with US technical. cryptologic support,
are expected to provide primary airborne coverage (EC-47) of South Vietnam
MR's 3 and 4. It is not feasible to consider Laotian or. Cambodian airborne
operations because:
(a) They do not have the special skills in sufficient numbers
.needed to fly the smaller aircraft on collection, and direction finding
missions.
(b) They have no existing capability to fly the larger
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(c) They do not have sufficient technical skills and data
needed to perform the collection. and direction finding functions.
b. Bearing in mind the ever changing situations which affect
locational requirements, NSA advises that the latest (as of 16 May 1973)
weekly fix requirements, developed by the Field Commander are as follows:
MR-1, 191; MR-2, 121; MR-3, 79; MR-4, 75; Laos, 180 and Cambodia 62.
These figures represent the Commander's interpretation of national, as
well as the tactical situation needs. Since the enemy must be communicating
by radio when ARDF missions are being flown a direct correlation cannot
be drawn between the number of hours to be flown, or mission allocations
per area and fix requirement ""saYisfactiob. It is true that: there is a
better chance to meet the desired fix rate if large numbers of missions
are flown, with long periods of time-over.-target.
c. With the reduction of U.S. resources in RVN as a result of the
"Treaty" a severe decline in our ability to follow the enemy was realized
by most consumers long ago.
3. What is the current disposition of US ARDF assets and their ability/
inability to operate effectively against targets in MR-1 from present
bases, in view of increased AAA/SAM threat in Laos and MR-l?
-a. Current six US Army U-21 (4-RU configured and 2-JU confi ured)
aircraft are based at Udorn RTAFB:1,
b. Factors which impact on the ability to fly sorties into RVN
MR-1 are:
Command restriction on all US manned aircraft not to overfly or
approach within five nautical miles of AAA operating areas in Laos
(high threat areas). Thus direct ingress/egress into MR-1 is not possible
due to the mounting AAA threat in Steel Tiger, thereby necessitating
circuitous routing to the South through Northern Cambodia, the RVN
Central Highlands, and back north into the target area. (See maps at
TAB "A." for disposition of AAA forces in Laos and TAB "B" for the latest
.PACAF no-fly areas). Additionally, there are no-fly restrictions con-
cerning ICCS flight corridors in RVN which impact on the Commands
ability to place aircraft in the desired target area at the proper time.
Staging I would limit the EC-47 to less than one hour time-over-
target. Presently,stationing of additional aircraft I is im ractic2.5X1
due to ramp space and maintenance limitations. However, using Il as a 25XX1
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4. What is the current disposition of CVN ARDF assets and their ability/
inability to routinely operate from present bases against targets in NR-l?
a. Currently the GVN have ten EC--47 aircraft based at Da Nang, 23
EC-47 aircraft based at Tan Son Nhut (TSN), and three U-6 aircraft at
Can Tho.
b. Factors which impact on GVN ARDF assets operating against targets
in MR-?1 are:
(1) The present programmed frag rate for aircraft staging from
DA Nang' i:s four 'sorties p61'. clay in Southern Mk-1., The reduced. frag
rata (less than 50 percent of available aircraft) is due to the lack of
trained_ crews. In addition to manning shortages, three other factors
impact on the VNAF's ability to effectively cover MR l: weather, main-
tenance and most important the enemy AAA/SAM threat. (See maps at
TAB "C" for disposition of enemy AM units in MR-1.) The service ceiling,
speed and maneuverability of the EGW47 platform make. it imprudent to
expose sensitive and limited. resources to high risks. Unfortunately
these high risk/th-re.at areas are generally the very areas of highest
intelligence interest. Rebasing of aircraft in this instance offers
no solution to the problem. It is to be noted that no US EC-47 air-
craft were tasked into the northern MR-1 area since the Easter offensive
of last year; coverage was provided. by US Army U--2l. assets which were
more survivable in the hostile environment then extant. The increased
threat would now preclude even U-21 utilization. Regarding the aircraft
based at. TSN and Can Tho. Even without the enemy air defense threat,
these assets do not have flying time capability to cover MR-1 targets.
Equally important, they are required to cover targets of high interest
to the GVN in MR' s 3 and 4 and to help meet US fix requirements for
these areas. (See maps at TAB D and. E for disposition of enemy forces
.in MR 3 and 4) .
5. What is the current allocation of ARDF missions for Laos (North and
South), MR-1, MR-2, and. Cambodia, to include rational for allocation?
a. Allocation of US ARD1'. sorties is accomplished weekly by the
ARDF Coordination Center (ACC) Il and approved by the J-2, USSAG. 25X1
For the period 14---25 May allocations are as follows: Barrel Roll/PDJ,
21 sorties; Steel Tiger, 21 sorties; Cambodia, 20 sorties; and RVN !,M-2
(ARDF areas 6 and 7), 35 sorties.
b. Allocation priorities are determined within USSAG J-2, based upon
weekly requests submitted by US activities in SEA. Specifically, SSO
Laos (for AmEmb Vientiane), DAO/DODSPECREP Saigon, USSAG J-2 elements,
command priorities and the ongoing tactical activity.
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c. The-allocation of 20 plus sorties to cover Cambodian targets is
questioned by NSA, who contends that a lesser number would be adequate.
In response, J-2'USSAG advised that due to the general lack of intelli-
gence information (including COMINT), that the situation and priority
of our operational effort against forces in Cambodia had dictated and
justified such. allocations. The goal, with this level. of allocation,
by other intelligence collection resources. (See maps at TATS F-J for
disposition of enemy forces in Cambodia, Laos and RVN MR-2.)
6. Are there any operational or political conunitments which govern
coverage of MR-1 by US vs GVN assets?
a. Tlier~e are no 'knotan -political ~ commitments ~rhicli wciiil.d. preclude
the use of US ARDF resources in MR?i., nor has there been a formalization
of operating agreements as to areas of responsibility insofar as ARDF
coverage is concerned. It is mutually agreed, by the field conmiander,
the GVN and. NSA, and the rest of the intelligence community must support
the agreement, that duplication will be avoided. The present delineation
evolved around the constraints of available bases (both V1~AF an.d25X1
the location of ground based SIGINT support functions. Hence, the VNAF
flies MR--l based out of Da Nang and supported by the Da Nang processing
center. VNAF also flies MR's 2 and 4 based out of TSN and Can Tho, sup-
ported by the Saigon processing center and the Can Tho site, respectively,
MR--2 'is covered by US ARDF resources based at iI 25X1
b. The mission coordination between USSAG and DGTS Saigon i.s
accomplished by interface through DAO Saigon Special Representative
(NCFR-VN) via the ACC. This is accomplished weekly as a matter of
routine when preparing the upcoming tasking cycle, and on an Ad Hoc
basis as developing situations dictate. Through ongoing coordination
this area coverage arrangement has proven to be the most effective means
of managing the limited resources available.
7. What is the adequacy of technical. data now available for the ARDF
effort?
Technical data available to the ARDF problem is judged to be acceptable
in terms of both completeness and accuracy, and in consonance with the
degree of COMINT analytical development.
8. What ar_e the indications fr..om ARDF and other sources (MRtDF, COMINT
etc.), of current levels of enemy activity in MR-1?
a. A general paucity of all-source intelligence information,
including SIGINT and APDF, limits the intelligence community's ability
to accurately determine enemy order of battle, capabilities and intentions
in MR-l. Although exact quantities are not known, indications are that
the enemy has been able to infiltrate both personnel. and logistical stores
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to reconstitute lxis forcrs in the area. Units are probably combat
effective and capable of conducta.rxg offensive operations. The enemy
appa.r.ently intencl.s to maintaa.n a vi.o~, Pen L, B~ko~, Kep,