AIR ACTIVITY IN SOUTHEAST ASIA

• Document Type: CREST
• Collection: Library of Congress
• Document Number (FOIA) /ESDN (CREST): LOC-HAK-511-4-8-1
• Release Decision: RIPLIM
• Original Classification: T
• Document Page Count: 11
• Document Creation Date: January 11, 2017
• Document Release Date: November 7, 2012
• Sequence Number: 8
• Publication Date: June 15, 1970
• Content Type: MEMO

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NATIONAL SECURITY COUNCIL
WASHINGTON, D.O. 20505
June 15, 1970
THE SECRETARY OF STATE
THE SECRETARY OF DEFENSE
THE DIRECTOR, CENTRAL INTELLIGENCE AGENCY
SUBJECT: Air Activity in Southeast Asia
The President has directed the preparation of an evaluation of our
current air activities in Southeast Asia and alternative programs for
FY71.
- describe current Allied air activity by mission and target
in each operational area: South Vietnam, Southern Laos, Northern
Laos, and Cambodia;
-- analyze the effectiveness of air activity :in performing its
major missions, as determined by its immediate effects (trucks
destroyed, enemy killed, etc.) and the implications of these effects
for the enemy's military capability in Laos, Cambodia.and South
Vietnam;
-- evaluate the effectiveness of alternative sortie levels and
munitions loadings for each major mission in each operational area;
-- formulate alternative tactical air and B-52 programs for
Southeast Asia in FY 71 and their rationales;
-- determine the force levels and mixes required for alternative
air programs including some consideration of possible improvements
in the efficiency of our air activities through changes in the aircraft,
ordnance, etc. used;
NSS, ARMY, DIA,
USAF, OSD review
completed.
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-- the budgetary requirements for alternative air programs.
This evaluation shall be prepared by the Vietnam Special Studies
Group Working Group. The study shall be completed by July 15
and, following VSSG review, submitted to the President.
I 'r . - fV
Henry Kissinger
cc: The Chairman, Joint Chiefs of Staff
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MI51YLULtAIV 3
U U IAA
THE PIUSIDENT HAS SEEN 1P
THE WHITE HOUSE
ACTION ?' '-S -14N - 4D ZV(
June 6, 1970
MEMORANDUM FOR DR. KISSINGER
FROM: Laurence E. Lynn, Jr.
SUBJECT: Air Activity in Southeast Asia
Several months ago, the President asked for an evaluation of the
effectiveness of our interdiction campaign in Laos. More recently,
you approved seeking permission for a VSSG review of our air
activity throughout Southeast Asia.
This memo discusses the issues involved in our Laos campaign,
also summarized in a memo for the President, and presents a
study plan for the President's approval (Tab A).
Air Activity in Southeast Asia
With the cessation of the bombing of North Vietnam, U. S. air
activity has been focused on three principal areas:
--- In North Laos, our support of the CIA's irregulars has
required a rapidly increasing U. S. air effort with about 6, 000
attack sorties per month.
-- In South Laos, continued interdiction of the enemy's
infiltration involved about 7, 500 sorties per month.
-- In South Vietnam, attacks on enemy base areas and support
of Allied ground forces require about 13, 500 sorties per month.
Each of these operational areas has its own distinct operational
character. While I will discuss below the character of our
interdiction campaign in Southern Laos, a similar, if not more
expert, evaluation of our efforts in South Vietnam and North Laos
is also needed. With the granting of authority for a small inter-
diction program in Northeast Cambodia, we also need to look
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into the problems there, particularly those associated with the
starting of a new enemy logistical system along the Se Kong
and Mekong rivers.
Our Bombing Campaign in South Laos
Since its inception in 1964, the principal focus of our bombing
campaign in South Laos has been on destroying supplies available for
shipment to South Vietnam. To do this we attack moving trucks,
truck parks, and storage sites with half or more of our average of
7, 5000 sorties monthly. The remainder of our effort is aimed at
reducing the capacity of the Laotian road-net by attacking the roads
themselves and the crews that attempt to repair them.
The air resources that we use to carry on this campaign include:
-- Gunships. These converted cargo planes (C-130 and
C-123s) are equipped with side-firing guns guided by night
observation devices and covert illuminators. They are used to
attack moving trucks in largely undefended areas.
-- Slow-Moving Aircraft. These tactical aircraft (mainly A-Is
and T-38s) are equipped with guns for straffing and conventional
bombs but not special night observation devices. Like the gunships,
they are used mainly to attack moving trucks in lightly defended
areas.
-- Fast-Moving Aircraft. These tactical aircraft (largely F-4s)
are largely equipped in the same manner as the slower tactical air-
craft. They are used to suppress enemy AAA fire and to attack
targets in defended areas, particularly during day-time.
The strengths and weaknesses of the U. S. interdiction effort in
Laos, particularly against moving trucks, largely result from the
operational characteristics of our aircraft:
-- Target Acquisition. Our tactical aircraft, except for the
gunships, are unable to locate their own targets. Instead, targets
are located by FACs which then 25X1
illuminate or mark the area with flares and lead the fighter pilot
to the target. The noise, delay,* and illumination involved in locating
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a target give the enemy warning of attack and time to take counter-
measures.
- - Bombing Accuracy. Our tactical aircraft generally bomb
from at least 2, 000 feet during the night and higher during daytime.
With unguided ordnance, the expected error during daytime when
most bombing is done is about 300 feet for a slow-moving plane
(A-1) and 500 feet for a fast-moving aircraft (F-4). During night-
time when there is bad weather the expected errors for both air-
craft types are 1000 feet or more. These bombing errors are very
large given the target size presented by a moving truck or the small
storage dumps typical of Laos. With laser-guided bombs, these
errors could be substantially reduced but only few bombs of this
type are available and few planes arch equipped to use them.
Bomb Lethality. Our standard 500-pound bomb has a lethal
area of about 75 square feet against a truck. With this lethal area
and the average nighttime bombing accuracy, it usually takes 10
500-pound bombs -- two full loads of a slow-moving A-1 -- to ensure
the destruction of a single truck. For the fast-moving F-4, four
sorties and up to twenty 500-pound bombs are required to accomplish
this same result. While other types of bombs have a greater lethal
area -- firebombs and bomblets -- conventional "iron" bombs are
the most frequently used ordnance.
The enemy knows these characteristics of the U. S. aircraft and the
tactics used in our bombing effort. He has put great effort and
ingenuity into countermeasures that reduce the effecti'?reness of our
bombing:
-- Weather. The enemy operates almost entirely at night or in
bad weather when U. S. aircraft are unable to acquire targets visually
without warning the enemy and when bombing accuracies are greatly
reduced. Because the enemy roadnets are operated far below their
capacity, the enemy can move required supplies without exposing
them to interdiction during periods of daylight and good weather.
- Dispersal. The enemy has dispersed his truck convoys and
storage-areas so as to reduce target size.- Convoyed trucks are often-
spaced about 200 yards apart so that no more than one can be
destroyed by a single aircraft. Small storage areas containing five
to ten.tons of supplies are sprinkled throughout the countryside.
O
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w
-- Cam.ouflige. The enemy has expertly camouflaged his truck
and storage are.s greatly increasing the difficulties of locating them
in thickly-forested and mountainous Laos. While our
they are not co
pletely successful.
-- Bomb Cduntermeasures. The enemy has learned to locate and
disarm the minas and delayed-fuse bombs we use. Against the MK-36
anti-vehicular mine, for example, the enemy knows the location of the
mine because its tail assembly sticks out of the ground after impact.
Because the mine uses a magnetic fuse, the enemy, knowing its
location, can trigger it easily from a safe distance using a magnetic
coil. While some delay and inconvenience is caused, the enemy does
not suffer substantial losses.
-- Road Repair. The enemy has scattered road repair crews and
materials along all the principal routes through Laos. While the U. S.
attempts to forestall repair by the use of anti-personnel mines and
delayed-fuse bombs, the enemy has been able to repair any damage
to its roads in less than two days with only a few hours usually
required.
Because of these effective enemy countermeasures and our technical
limitations, the air interdiction effort has always been relatively
inefficient though not without effect. To evaluate these effects, we
turn next to a more detailed discussion of truck and supply destruction
and road interdiction.
Truck Destruction
Because of these difficulties, U. S. pilots in Laos report that only
one out of every five enemy trucks sighted in Laos is destroyed and
only a fraction of the actual movement is probably sighted. However,
in spite of this acknowledged inefficiency, our pilots also report that
they destroyed more. than 5, 000 trucks per year in 1968 and 1969 and
more than 5, 000 in the current dry season.
While these pilot reports represent the best information available
and, with minor adjustments, are accepted by the Air Force and DIA,
they may seriously overstate our actual destruction of trucks for the
following reasons:
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25X1
25X1
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e .G. v.c v.uv.~aL
-- Pilot Error. Rewarded on the basis of reported destruction,
U. S. pilots have an obvious incentive to inflate the damage reported.
While the pilots reports can be checked against the reports of FACs,
there is little joubt that both probably seriously overstate the damage
suffered by th el, enemy. Following the Korean War, detailed analysis
showed that individual pilots reported as much as ten times as much
destruction as ad actually occurred because they tended to restrike
over and over fargets already destroyed. Because of poor visibility
caused by the height, the weather and effects of exploding bombs,
pilots and FAC~s are often unable to accurately assess the damage
they have caused.
-- Other Evidence. Post-strike photography has never revealed
the large numbers of disabled trucks in Laos expected from pilot
reports. Our best intelligence is that the enemy's total inventory
of trucks in Laos (1000 to 1400 vehicles) is substantially less than
the trucks reported destroyed even in some periods as short as a
month.
For these reasons, I believe it is likely that our estimates of enemy
truck losses, based ~n pilot reports, are probably substantially
overstated. This judgment is informally shared by many individuals
in the services.
Secondary Fires and Explosions
Besides attacking moving trucks, our bombing effort also hits enemy
storage areas and truck parks. The assessment of damage done to
these facilities is based largely on the number of secondary fires and
explosions reported by U. S. pilots. During the current dry season,
our pilots have reported about 20, 000 secondary fires and explosions
compared to 13, 000 in the same period last year. In general, these
secondary fires account for about two-thirds of the total supplies the
DIA and the Air Force report that the enemy has lost through our
air campaign.
However, there is no reliable means of checking these reported
results or determining their significance in terms of enemy personnel
and supply losses. For purposes of analysis, the Air Force and DIA
assign an estimate of the supply tonnage lost in each secondary
explosions but these estimates represent little more than arbitrary
assumptions that cannot- be independently corroborated and are
undoubtedly subject to serious errors.
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Enemy Supply Flows
Based on the u certainties of the reported destruction, the intelligence
community has been at odds over the extent to which enemy supplies
in Laos are actually destroyed by our bombing effort and whether,
given the know supply flows into Laos and consumption there, the,
enemy has mo a or less supplies available than he needs to meet
his requirements in South Vietnam. The two principal views are:
-- The Air Force and DIA officially accept the pilot's reports
of trucks destroyed and secondary explosions at face value.
Extrapolating these effects into supplies lost to the enemy, they
find that the enemy is losing or consuming in Laos more supplies
than he has been bringing into Laos. They conclude, therefore,
that the enemy has only maintained the flow of supplies into South
Vietnam by depleting stockpiles previously built up in Laos.
-- The CIA believes that the actual supplies lost to the enemy
are substantially less than reported by our pilots. 25X1
they believe that the enemy loses about 25X1
25% of his supply flow in Laos and that consequently the enemy has
more supplies available in Laos than needed to both supply,South
Vietnam and build substantial stockpiles in Laos.
Thus, there is a basic disagreement about the enemy's supply
situation in Laos. Aside from'the factors, such an overstatement
of enemy losses already mentioned, the principal reason for
supporting the CIA view is that our information on actual enemy
supply flows into South Vietnam shows that the enemy is able to
vary his supply flows greatly, increasing them to levels far beyond
his minimal requirements even during periods of intense bombing.
During January and February, 1970, the enemy's actual supply flows
were almost four times the estimated requirements of VC/NVA forces
in SVN during the same period. If these flows occurred, I believe
that they prove beyond a reasonable doubt that our interdiction effort
has not limited substantial increases in enemy supply flows. This.
direct evidence is corroborated by what we know of the capability of
the enemy supply system: its excess road and truck capacity, and
relatively low manpower requirements.
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On the other hand, if the pilot reports and the Air Force /DIA view
of their implic Lions are correct, they form a strong argument
that the interdiction campaign' in South Laos has effectively forced
the enemy to deplete his stockpiles of war material there and may
have reduced enemy supply flows into South Vietnam below its
requirements there for some periods.
Other Bombing' Effects
Although our bombing may not effectively reduce enemy activity
in South Vietnam, it does increase the resources required from
North Vietnam and its allies to support its forces and continuously
disrupts enemy logistical activity creating substantial managerial
difficulties for North Vietnam.
The cost to North Vietnam consists of the supplies destroyed and
men killed by our bombing. Since 1964, about 15, 000 trucks and
70, 000 tons of supplies with an estimated value of $167 million have
been reported destroyed. While almost all of this material is
provided by Hanoi's allies - not North Vietnam itself - it undoubtedly
represents some loss to North Vietnam.
Because our bombing is directed mainly-against logistical targets it
has not cost the enemy dearly in manpower. Although the incidence of
disease among infiltrating personnel is high, most of their personnel
recover and few permanent losses (about 10% of the infiltrators)
result from it. Likewise, while the North Vietnamese have to maintain
some manpower in Laos to offset the effects of bombing that could
otherwise be redeployed, the numbers involved (10, 000 to 20, 000 men)
are not substantial.
In addition to increasing the cost to North Vietnam, the bombing in
Laos also disrupts the flow of supplies to base camps in South Vietnam.
While little is known on this point, I think that these disruptions
probably have a very limited impact on enemy operations within South
Vietnam itself, because the enemy has been able to maintain his
overall supply flows at or above required levels. Though enemy supply
shortages are reported in South Vietnam, they are usually caused by
forward.distribution problems - inadequate numbers of laborers,- allied
distraction of VC storage areas, and poor transportation - not an overall
shortage of supplies coming from Laos.
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Even though the disruptive and cost-increasing effects of our bombing
are relatively slight, I nevertheless think that they are important enough
so that some interdiction campaign can be justified.
There are, however, numerous improvements in our present campaign
that would achieve these results at a decreased cost or increase our
effectiveness at current expenditure levels.
Some possible improvements are:
-- Wet Season Bombing. The Air Force has usually continued its
interdiction effort in South Laos during the wet season at only .o
slightly-reduced levels (5, 000 to 7, 000 sorties monthly). Because
the enemy has sharply reduced his supply activity during these
periods, these sorties have been much less effective than sorties
made during the dry season when targets are plentiful.
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-- Aircraft. The fast-moving jet aircraft (F-4s) used by the Air
Force are much less effective than either slow-moving (A-1 or A-20)
or gunships (AC-130) aircraft at destroying enemy supplies. Never-
theless, because of its desire to keep fast-moving aircraft in its
post war inventory, the Air Force has consistently redeployed slow-
moving aircraft rather than fast-moving aircraft and has never
deployed gunships in appropriate numbers. As a result, our
interdiction effort is probably less effective and more costly than it
needs to be.
-- Ordnance. The development of new ordnance suitable for Laos
and the reduction of ordnance already developed suffers from many
shortcomings. We still largely use conventional "iron" ordnance in
Laos even though we have every reason to believe that CBUs, napalm
and laser-guided bombs are more effective.
With DOD plans to reduce our overall air effort in Southeast Asia, it
is critical that we develop as efficient an air effort in Laos as possible.
However, even if our air activities in Laos were as efficient as
possible, we would still face the difficult strategic problems created
by_a_budgetary squeeze on our air activity including:
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Determining the overall sortie level in Si i theast. Asia
required to support our military and diplomatic strategy.
-- Allocating these sorties among the various operational areas.
missions within those areas,
-- Funding the level of air activity that appears desirable on
strategic grounds.
a..study. effort answering these questions. I suggest that you seek
I have prepared a. directive from you to. the.VSSG designed to start
the President's support for the study and faxniliarize.him to a
greater extent with the. nature of the problem,.
That you forward the ,enclosed. memo (Tab.A). to the President
RECOMMENDATION
Asia.
asking his" ?a .roval of a VSSG evaluation of, air activity in Southeast
Approve Disapprove
If you feel:the memorandum for the President is unnnecessary,
recommend you sign the study. directive. (Tab B)
Attachments
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