Tuy Hoa Air Base
31st SPS
submitted by Dick Larsen


My name is Dick Larsen and I was with the 31st TFW Public Information Office from Dec 1967 to Dec. 1968. I have a few color slides taken of Security Police activities at the base and will scan them off and send them in. I also wanted to ask if you have any info about the VC attack on the base on July 27, 1968? I was then Wing Historian then and wrote the unit history about the attack.

Thanks, Dick Larsen

"End of Tour Report"
prepared by Col. Abner M. Aust Jr.
Period of 3 May 1968 through 8 February 1969

This document is excerpted from the "End of Tour Report" prepared by Col. Abner M. Aust Jr., commander of the 31st Tactical Fighter Wing, Tuy Hoa AB, Vietnam. The report covers the period 3 May 1968 through 8 February 1969. This excerpt consists of pages 30-42 of Col. Aust's report. The document originally was classified SECRET but is now unclassified in accordance with Executive Order 12958.

Tuy Hoa Air Base itself was attacked only once during this period. The base was penetrated at 0137 hours on 29 July 68 by a small size sapper unit. It is believed that the group consisted of 12 VC and their objective was to destroy parked aircraft, fuel storage and ammunition. The attack against the parked aircraft was successful and they inflicted the following damage:

  • two (2) C-130 aircraft destroyed
  • five (5) C-130 aircraft damaged
  • one (1) C-47 aircraft damaged
  • one (1) F-100 aircraft damaged

Four persons were wounded however, only one was wounded seriously enough to require evacuation. Before the sappers could reach the POL and ammunition dump they were detected and engaged. The VC losses were nine (9) killed. The bodies carried the following equipment:

  • two (2) bangalore torpedoes
  • two (2) B-40 rocket launchers
  • one (1) 13-40 rocket
  • eleven (11) satchel charges
  • nineteen (19) hand grenades
  • two (2) AK 47 weapons
  • five (5) magazines AK 47 ammunition
  • one (1) automatic hand gun (make unknown)

The attack was probably considered by the enemy as highly successful, however, the price he paid may have been influential in delaying subsequent attacks. Having exchanged nine men for two aircraft destroyed and 7 damaged may be considered worthwhile to the enemy. Prior to the attack on 29 July 1968 elint activities in the area as was known to the 31st Tactical Fighter Wing were normal. Snooper operations did not reveal activities of an unusual nature.

The weather conditions on the night of 28-29 July were excellent in favor of attack. This was not a unique situation for the Tuy Hoa area at this time of the year. Clear skies and unlimited visibility were reported from 2200 hours on the 28th of July through 0300 hours of the 29th of July. There were a little over eleven (11) hours of darkness and the moon illumination was 7%.

Intelligency agencies in the local area generally agreed about VC plans and intentions to conduct harassments and ground assault attack on Tuy Hoa City and local allied installations before the end of July 1968. However, such plans and intentions were standard VC practices in this area. Source reports did indicate an increase in VC action during the latter part of July, but the probability of VC attacks during this period did not appear to be any greater than during previous periods, when numerous (sic) reports were received predicting attacks on allied installations in the Tuy Hoa area. Although prior to 29 July 68, sapper attacks on the Tuy Hoa Air Base had not been attempted, they were always recognized as a threat.

C. Base Defense Responsibilities:

1. Internal:

The 31st SPS is responsible for the defense of the personnel and resources of Tuy Hoa Air Base, RVN. This mission is accomplished by using professional Security Policemen and fully trained augmentation personnel from other base and tenant units. During daylight hours under normal alert conditions, the security posture is designated basically for surveillance. The entire perimeter of the installation is kept under observation by 15 Observation Towers and two Gun Positions. Immediate fire support is provided by three Security Alert Teams (SAT) and two Reserve Security Alert Teams (RSAT) of six men each. In addition, the night flight can be formed into six fire teams of twenty-five men each within thirty minutes.

Every night over 50% of the SPS personnel are on duty. At this time the perimeter is reinforced with thirty-six M60 Machine-gun positions of two men each and three additional Security Alert Teams. Close in protection is provided for the vital resources within the installation by posted sentries. Immediate fire support is supplemented by two Reserve Security Alert Teams of six men each and four fire teams of twenty-five security policemen each which can be ready for deployment in less than thirty minutes.

Augmentee support is provided by 245 specially trained Augmentees and 59 teams of 25 trained men each that are used to man the entire Main Line of Resistance whenever needed.

MLR training consists of four hours per month in the following subjects; one hour in deployment to the individual MLR positions with the following subjects stressed: Cover and concealment, field of fire, night vision, communications, and squad tactics utilized for deployment and search missions. Three hours of classes and actual weapons firing are then given at the security police range. Stressed here are: MACV challenging procedures, rules of engagement, Guard Orders, use of the gas mask, complete disassembly of the weapon (M16), care and cleaning, combat firing positions with the M16, use of the slap flare, alert conditions, where to report during Red Options, and actual firing of the M16. Each individual fires four (4) eighteen round magazines of ammunition.

Initial Augmentee Training, consists of approximately 18 hours plus one 8 hour tour of duty with "Tiger Flight" (night security flight). Augmentees are trained on all the items that MLR members receive with the addition of M60 machine-gun, OPLAN 207-69, Mission of Augmentees, Intelligence briefing by SPS Intel Section, Security Alert Team Procedures, mines and booby traps, squad tactics, Sanitized Fire Zone, and POWs. Approximately six (6) hours are allotted for care and cleaning of the M16 and M60, disassembly, and actual firing of' 90 rounds of' M16, and 100 rounds with the M60. Recurring Augmentee training is a repeat of the above and is conducted once per month for approximately (4) hours.

In conjunction with the above, each fighter squadron is responsible for arming 20 maintenance personnel upon declaration of security alert condition Red Option I. This is for immediate flight line defense. Each squadron's expediter truck has 20 M16A rifles and 100 magazines of ammunition on board at all times. These trucks are deployed to the maintenance flight line area upon alert. The 5 teams are initially posted by Security Police NCOs who give the team leaders instructions and a non-tactical radio to maintain contact with CSC. CSC controls all firing by these teams.

2. External:

The external defense of the installation depends on the following friendly forces: US Air Force - An AC-47 Flare/Gunship provided by the 4th Special Operations Squadron flies constant aerial support nightly from 2200 to 0300 hours.

US Army Forces - The area generally is devoid of US Army combat units. The main contingent of Army personnel is located approximately 3 miles south of the base at Headquarters, Tuy Hoa Sub Area Command, (THSAC). "C" CO (undermanned) of the 54th Infantry is based there with the primary mission of security for THSAC and nightly patrols of the POL pipeline. Medical, engineering and other support elements are also present in the area but have little significance in terms of security for Tuy Hoa Air Base. THSAC maintains the Installation Coordination Center (ICC) which supports this base. "C" Battery, 6/32nd Artillery is armed with two 8 inch two 155 MM artillery pieces. Helicopter gunships from the 268th Aviation Battalion are available in case of an attack against the base.

US/RVN Naval Forces - RVN 24th Junk Division has ten junk patrol vessels and one US Navy patrol vessel which patrol the South China Sea on the eastern boundary of the base. These vessels can respond to our water boundary from their most distant point within thirty minutes. Central Security Control maintains constant communications with this unit. US Naval Swift Boats from Operation Market Time are available at Song Cau Bay. CSC maintains radio contact with them, and they can respond to our perimeter within twenty minutes.

ARVN/Popular Forces - No personnel of the 22nd Division, 47th Regiment and PF personnel of the Hieu Xong District are stationed nearby. These forces would be used only in an attempt to intercept and destroy the enemy prior or during an attack on the installation. ARVN artillery positions located approximately 5000 meters from the base can provide fire support. The most significant contribution of ARVN ground forces in support of this base is as a blocking force in the valley to intercept the enemy.

ROK Forces - 28th Regiment of the 9th White Horse Division is tasked with the ground tactical responsibility for this section of Phu Yen Province. This Regiment consists of 3 battalions of about one thousand men each. It also includes three artillery batteries with 105mm and 155mm Howitzers. The regiment operates continually in CO and battalion sized units in the mountainous area near the base. These highly professional ROK troops provide intelligence and keep the enemy divided into small groups and constantly on the move. The ROK artillery is capable of firing pre-planned illumination or HE concentrations for the installation. Two companies of ROK Army personnel have been designated to support our Base in the event of' enemy attack. These companies are maintained in readiness at the ROKA compound.

3. Operations Summary:

The security posture of an installation is not a static concept. Physical security facilities are constantly being improved and security tactics are varied as lessons are learned and enemy tactics change. All security police personnel are continually trained in the proper actions during mortar attacks. The importance of taking sufficient cover and still maintaining the required surveillance over all areas is stressed. Direction of muzzle flashes is highlighted and additional training given in correctly pinpointing off-base locations using precise map coordinates.

During the months of May and June special attention was given to reinforcing the perimeter fencing. Vietnamese crews, supervised by expert security policemen worked constantly to strengthen the north perimeter fence. This was accomplished by combining triple standard concertina wire with the MACV weave The need for elevated gun positions was evident, and July construction started on these positions. Self help crews of security policemen constructed three elevated gun positions in the rock crusher area, located on the north side of the base. These fire positions replaced three gun bunkers which were unsuitable due to their limited fields of surveillance and fire resulting from their low elevation and proximity to the perimeter fence. During July another elevated gun position was constructed in the rice paddy area. This area presents a problem to the defense of the installation since it affords excellent concealment for enemy penetrators. To reduce this undesirable condition additional gun positions were constructed.

As a result of the lessons learned from the 29 July attack the following actions were taken to improve the security posture:

  • Observation Tower 8 was moved across the road to a position more strategic which increased considerably its field of fire and surveillance capability.
  • Three additional gun positions were constructed by security policemen in the rice paddy area.
  • Gun positions 17 and 18 were relocated away from the perimeter fence and constructed as elevated bunkers. This change provided excellent coverage for the area in front of these posts
  • Manning procedures were revised to insure that vital gun positions were manned at all times. This caused the cancellation of all days off for security police personnel, a condition which lasted for approximately four months.
  • The fence adjacent to the rice paddy area was reinforced with MACV weave by a crew of Vietnamese Nationals supervised by CE personnel.
  • A work order was submitted requesting additional gun positions in the rice paddy area and further requesting that all gun positions be reconstructed in a combination cement bunker with observation tower on top.
  • Eight new gun positions were constructed adjacent to the North side of' the aircraft parking apron; these positions are manned during the hours of darkness.

In August the security posture was enhanced by the receipt of three 81mm mortar launchers. Two permanent mortar positions were constructed by security policemen personnel immediately, one in front of CSC and the other one north of the bomb storage area. These mortars have proved very valuable in providing vital illumination during sweeps and suspected incidents. They can also be used for firing of HE in the event of an enemy attack. In September work started on the perimeter mine fields. A special security police team of three men was formed and trained in laying M-14 Anti personnel mines. Approximately one fifth of the base perimeter is mined at this time.

During the month of October, the spare 81mm mortar was mounted on the back of a ' ton weapons carrier on a trial basis. Due to outstanding success, it has remained mounted as a mobile mortar. It provides a mobile capability for illumination or HE fire which greatly assists in providing security at night. The was completed for all the perimeter except the beach area during this month. This was a very significant increase in our surveillance capability, because it gives us full illumination of the entire ground perimeter.

Due to continued undermanning, the SPS was augmented in November by a 34 man section from the 821st Combat SPS. They were assigned the responsibility for securing sector II, which is composed mainly of the aircraft parking area, munitions and POL storage areas. The deployment of this unit not only resulted in a greater security for the base, but also gave our Security Police personnel opportunity for some time off. This month saw the construction of the first reinforced gun bunker which was made out of a standard Observation Tower. This self help project by Security Police personnel converted Observation Tower three into an impregnable machine gun bunker. We are planning to redo all the observation towers in this fashion.

In November, permanent pole lighting was erected along the aircraft parking area on the runway side. This project greatly enhanced the security of the flight line. Machine gun positions were built on the edge of the apron and are fully manned every night. Also the first three XM 706 Armored Vehicles were received by this unit. A training program was immediately launched and in a 10 day period all necessary personnel were qualified to operate the armored vehicles. These vehicles provide superior transportation and deployment when under fire for the two RSAT elements and a six man QRT manned during the high threat hours. Recently a crew of Vietnamese Nationals, supervised by Security Police personnel, started erecting triple standard concertina wire fence on the south side of the beach perimeter. This project is now approximately 15% complete and should be finished within two months. Construction of' the new Central Security Control building was started in December with completion date expected on or about 1 March 1969.

D. Planning For Base Defense:

In later sections, comments will be made pertaining to the favorable aspects of the Tuy Hoa Base Development. As our investments, commitments, and operational capabilities have increased, a simultaneous increase in hostile threat must be assumed. Consequently, much effort has been exerted to strengthen our defensive posture, particularly since the Tet Offensive of 1968.

During the past year, protective evaluations by Base Civil Engineers in conjunction with Security Police have revealed several glaring deficiencies. Most obvious is the location of the perimeter road directly adjacent to the perimeter fence on the western and southern boundaries of the base. These same areas have been identified as the sources of highest threat. The close relationship of the two has allowed only the erection of a single row of fence. Optimal perimeter defenses generally consist of two rows of fencing approximately 100' apart, the interior area being thoroughly mined and wired for flares. The proximity of road and fence caused further problems during the installation of a perimeter lighting system. Erection of light poles directly above the wire would have made them highly vulnerable to hostile action, hence, they were placed behind the road, allowing a 40' separation to the outermost boundary.

The first problem is obvious. Resupply of gun positions, towers and post during attack, as well as routine surveillance patrols, must be accomplished while fully illuminated to any hostile force. Secondly, in some areas, prime power was furnished by an overhead distribution system. Power may be disrupted by any conductive material across the lines.

Surveys of road locations on the western and southwestern perimeter reveal minimum distances to satisfy airfield criteria in accordance with AFM 86-8. Hence, the problem stems from lack of sufficient land acquisition, away from runway locations, to properly establish a defensive perimeter.

To satisfy land agreements with the Vietnamese Government, the National Coastal railroad which passed directly across the location of our runways, was relocated on a 3.2 mile track bed. The raised level of the bed, directly adjacent to the perimeter fence, has given the potential enemy an excellent attack cover. Once again, planning and approval was initiated with little thought to overall base defense.

As at most bases in Vietnam, all POL storage tanks are above ground. These are highly susceptible to mortar and rocket attack. At th, tanks are located as close as 1600' to the base perimeter, making them vulnerable to even small arms fire. Very similarly, the ammo storage area has been sited approximately the same distance from the southwestern perimeter, exposing it to the same type of threat.

The ammo area could have been sited further west towards the ocean, adding more than 1500' to the buffer zone. The relationship of the POL storage tanks to flight line refueling operations, is however, relatively optimal. An alternative existed in an underground storage system. Because of the easily excavated sandy soil, the task would have been more practical here than at most inland bases. Project documents have been submitted to fully revet all fuel storage facilities. However, the task to which we have been forced is an extremely large and costly one.

A related problem concerns approximately 12 miles of exposed, POL surface line from Vung Ro lay to the south. Maintained and operated to the base perimeter by the Army, two or three enemy disruptions of service per week are not uncommon. Direct offshore fuel supply definitely warranted more consideration during initial planning stages.

Lastly, the Turnkey project left a $55 million dollar investment, much of it consisting of structures, with practically no physical protection. Even critical facilities as the Command Post, TUCC, Disaster Control Center, and Communications Center were constructed as pre-engineered metal buildings without revetments or hardened cores. Some of these facilities have now been identified for full concrete hardening. Hardening of existing facilities is in most canes unpractical so that new structures are presently required. We Take Care of Our Own
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