This chapter briefly considers four aspects of physical defenses as they existed in Thailand from 1968 to 1972.

[No] effort is made to duplicate concepts discussed in PACAFM 207-25,

[Two] CHECO reports on base defense concepts and measures in the Republic of Vietnam provide additional information.   See footnote 123.

Active and Passive Defense Measures

The first "ring of defense" within the bounds of USAF responsibility was the base perimeter, usually composed of fence lines and other integrated [next page]

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[defenses,] all designed to expose the enemy to an increased risk of observation and detection. No base considered itself secure because of an inpenetrable perimeter[,]   See footnote 124.

[To] further aid in observation, herbicides were employed to assist in the difficult task of vegetation control.     Use of these agents was limited by such factors as the ROE and supply problems.

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Limitations

Geographic constraints provided many problems in the USAF base defense posture in Thailand.     Contiguous population centers at many of the bases severly limited opportunities for both observation and effective counterfire.     Further, tropical vegetation sided by seasonal monsoon rains grew almost faster than it could be controlled.     Dense jungles were rated as the greatest threat to the defenses at U-Tapao.   See footnote 137.     Other natural features such as streams [next page]

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U.S. Embassy's ROE also provided several limitations on physical defenses.     [Soil] sterilization and herbicide use was also approved in 1969, but these were subject to extensive coordination with local RTG authorities and final permission from the Embassy.     They could only be used on areas within the perimeter and under no circumstances could the vegetation control agents be used to clear areas of observation to fire off-base.     This lengthy [next page]

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[process,] and the inability to go beyond the fences, significantly limited the use of those agents at many bases.   See footnote 145.

The 1969 ROE required advanced approval of the Ambassador for all "new weapons" introduced into Thailand.   See footnote 146.

Base Analysis

Korat RTAFB

Vegetation control was a serious problem at this base in 1972, especially in the critical RTAF area near the end of the runway.     The dense growth offered opportunity for concealment in the area of contiguous to the unrevetted KC-135 parking ramp.     Further, vegetation was thick in many sectors of the concertina wire on the perimeter.     The base had received Embassy permission to use herbicides and just began that program in June.

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Nakon Phanom RTAFB

NKP had the usual rainy season vegetation problems, but heavy use of herbicides kept the growth under control in the fenced areas.     Interior vegetation was usually kept closely cut.

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Ubon had undertaken a unique approach to solve one of its problems, that of controlling off-base vegetation.     The ROE prohibited the use of herbicides outside the perimeter, but Base Civic Action undertook the project of having vegetation cleared 100 meters from the MMS area fence and had additionally contracted with local villagers to clear 150 meters of dense underbrush from around the base perimeter.     The project was inexpensive, cleared a wide field for observation, and put money into the local village, thereby helping to create good will.   See footnote 160.

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Vegetation control was all but impossible over the entire reservation.     Vegetation control was further hindered by the inability of the base to get herbicides through supply channels during the first half of 1972.

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Chapter IV

Conclusion

In 1968, air base defense in Thailand was in its infancy.     A series of sapper attacks over the next four years did much to hasten the evolution of defense concepts that were adapted in the effort to protect vital USAF resouces from such surreptitious assaults.


Footnotes (Declassified)

Footnote 123

Chapter III   (S) CHECO Report, RVN 66-68 Base Defense; (C) CHECO Report,
Local Base Defense in RVN, January 1969-June 1971,   Hq USAF, 14 Sep 71.
(Hereafter cited:   CHECO Report:   RVN 69-71 Base Defense)

Footnote 124       (C)   Maj Barger NKP interview.

Footnote 137       (C)   Maj Strayer U-Tapao interview.

Footnote 145       (C)   Maj Strayer U-Tapao interview.

Footnote 146       {C)   US Embassy 1969 ROE.

Footnote 160       Not released, classified.

Table of Contents

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Chapter II Base Defense Personnel and Programs - Limitations
Rules of Engagment (Pg-31) ROE remains classified Secret and not made available.
See FOIA request 20 Dec 07 for related ROE plans.     Correspondence

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E.   All new base defense planning, arrangements and major joint exercise proposals are to be coordinated in advance with the US Embassy so that due account can be taken of the vital necessity to balance political and military factors in base defense.



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J.   Approval to conduct soil sterilization and/or defoliation operation on or around US occuppied installations will be obtained from the US Embassy.     Coordination be affected with the local US consul where applicable.