US Defence against Standoff Attacks - Combat Experiences and Lessons Learned

Defence against Standoff Attacks


Combat experiences tended to indicate that the frequency and resultant damage of enemy standoff attacks against military installations in South Vietnam were, in most cases, directly proportionate to the effectiveness of countermeasures and internal protective measures which prevailed at each individual installation.

Here are excerpts from some of these combat experiences as revealed by combat after action and intelligence reports which best illustrate the NVA and VC methods of operation, employment tactics, effects of such attacks, and lessons learned from those attacks.


Da Nang Air Base.

At 0310, 27 February 1967, Da Nang air base was subject to a standoff attack. In this attack, 56 140mm rockets impacted on the air base proper and eight in the adjacent village (sixty-six were launched but only sixty-four impacts were recorded). The attack lasted less than 60 seconds. Eleven US military personnel were killed, 125 were wounded, 13 aircraft and various buildings and facilities were damaged. In addition, 35 Vietnamese civilians were killed and 50 wounded by rounds which impacted in the village adjacent to the air base. Prisoner of war interrogation reports obtained after the attack revealed the following:

During the afternoon of 26 February, while the rocket launch site was being surveyed, enemy forces of the VCR-20 Local Force Battalion met 130 NVA soldiers of an unknown unit and began moving east to the launch site from the Ba Na mountain area from a location in the vicinity of AT7970. During the initial part of the movement, each NVA soldier carried one 140mm launch tube on his back. Then the battalion reached a valley along the line of march, members of the R-20 battalion picked up 130 140mm rockets from a cache located in the vicinity of AT886700. Each rocket was placed on a bamboo vine-rope constructed stretcher. Two men were assigned to each stretcher which contained one rocket. Each rocket was carried in this manner until the battalion reached the Song Yen River. At this point, approximately 30 native watercraft with crews were waiting at the edge of the river.

The rockets were placed in the boats and then ground crew proceeded downstream. The porters walked along the edge of the stream as the boats moved to the vicinity of the launch site. At 2330 hours, the force reached the already surveyed firing positions. The porters off-loaded the rockets and took them to the launch site adjacent to the river, placing one rocket behind each of the preliminary emplacements.

The rocket crews immediately began preparing the launch positions, marked by a roped-off area, while another group began assembling the rockets for firing. i.e., unpacking, fusing, and installing the igniters. The firing pits were three to four feet long, eight to ten inches in depth and 20 to 24 inches in width. The earth from the pits was placed in front of the pits.

After final preparation of the firing positions, the rocket launcher tubes were positioned in the launch site. A bamboo pole was in place at the front and rear of the launch pit which served as an aiming device. These had been previously placed there by the survey crew. Final azimuth adjustments were accomplished by the rocket launch crew by reference to a white line painted along the top of the launcher.

As soon as the launchers were properly aligned, the fused rockets were inserted. Elevation of the launcher tube was adjusted by a notched peg. Wires were attached to the electrical igniter at the base of the round and then tied to the electrical alignment stake. A set of wires, acting as a common electrical system was then connected to the rear alignment stakes and spliced into the igniter wires already Installed in the rockets. These wires connected each fire control pit to 10 or 12 launch pits. Communication was established between the control pits and, on command, the rockets were ignited from an electrical source.

Although 134 launch pits were constructed, only 66 pits were effectively used. The rockets were fired in volleys from the line of launchers located at grid coordinates AT965697 firing first, followed by the rockets located at grid coordinates AT966695. All 66 rockets were fired within 30 to 45 seconds, with an estimated 20 seconds between volleys. Thirty-five rockets failed to ignite due to a malfunction in the electrical wiring system. One rocket jammed in the launch tube, causing the tube to be fired with the rocket, leaving the mounting board behind secured in position by stabilizing ropes.

The unit was forced to make a hasty withdrawal from the area before possible counterfire. This task was complicated because of the number of rockets that misfired. Valuable time was lost removing rockets from the launchers, and there was insufficient manpower to cope with the unexpected additional materiel to be evacuated. As a result, four launch tubes loaded with rockets were left at the launch site. Six unexploded rockets were placed in one of the firing pits. Two of these rockets were booby trapped with "mouse trap" pressure release detonators. Numerous rockets were thrown into the river and 101 rocket containers with various carrying devices were left behind.

... Thirty-one rockets were recovered from the river and four from launch tubes by US personnel ....

As reflected in this account, the initial movement of the rocket battalion, after rendezvousing with a NVA unit, began from the Ba Na mountain area in the vicinity of AT7970. The unit then proceeded to the Song Yen river and thence to the launch sites at grid coordinates AT965697 and AT964694, a distance of approximately 1700 meters. The rockets were picked up from a rocket cache at grid square AT8867 approximately 1500 meters, or a little less than a mile from the launch site.

From the above account, it appears that 23 rockets with containers were evacuated from the launch site.

In excess of 500 enemy personnel were involved in this operation.

Not reflected in the above account was the intelligence gathered prior to the attack. As reflected by the Combat Operations After Action Report following the attack, numerous intelligence reports and small unit contacts indicated that reconnaissance of Da Nang Air base was being conducted and that an attack was imminent.

The report Indicated that several friendly personnel were injured or mortally wounded while attempting to take cover in nearby bunkers.

Lai Khe Base Camp.

During the period 14 March 1968 through 13 April 1968, Lai Khe Base Camp was subject to 26 separate rocket attacks. As a result of these attacks, one US military was killed, 21 were wounded, two buildings were destroyed and five damaged. In addition, two vehicles were destroyed, six were damaged, and numerous small items of equipment were either destroyed or damaged.

The most significant aspect of these attacks was the fact that each lasted less than one minute and each was launched during daylight hours. This change in tactics was probably best explained by an enemy document captured during subsequent sweep operations approximately 15 kilometers from Lai Khe which stated:

....According to the situation, we can fire in the day or at night, but we will obtain more results if we fire during the day, because the enemy takes shelter at night...Therefore, we are required to clearly know the enemy situation....

During these attacks, a total of 83 rockets were fired (75-122mm and 8-107mm) with fuse setting "Quick." Rockets were fired individually and in salvo (one to five rockets per attack).

The Combat Operations After Action Report reflected the following concerning countermeasures in effect:

Counter rocket fires began no later than 2 minutes after impact in each case of incoming rounds. The Artillery which plans fires for Lai Khe base defense has a very extensive counter rocket program which was fired daily. The plan was updated daily based on the best intelligence on confirmed and suspected rocket launch sites. During the past month numerous destruction missions on bunker and storage complexes to the northwest of Lai Khe (rocket belt) resulted in secondary explosions. This would indicate probable rocket storage areas. In addition, the Division Artillery S2 Target Center planned daily intelligence targets in the "rocket belt" area .... The trails leading into the "rocket belt" area were interdicted daily in order to disrupt and increase the rocket resupply problem.

Light Fire Teams (LFT's) reacted to incoming rockets within 10 minutes. TAC Air reaction was between 5-30 minutes depending on whether or not the aircraft were airborne at the time. TAC Air was also utilized to destroy hard installations within the "rocket belt" area and for nightly SKYSPOTS. On numerous occasions LFT's and FAC's were on station, observed rockets being fired, and immediately expended in the area. However, due to the method of recent launchings and the fact that it takes so few people to set the rockets. up, It has been extremely difficult to Judge the effectiveness of artillery counter-fire and airstrikes. There has not been much equipment left on the ground to destroy after the rocket has been fired utilizing crude wooden bipod launchers and commo wire. In addition to LFT's and FAC'S, the Division utilized division artillery aerial observers and G-2 air observers and aircraft to conduct daily visual reconnaissance (VR) over the rocket belt area both during the day and night in order to bring Immediate effective fires upon rocket locations and, thus, greatly improved the effectiveness of the counter-rocket program.

Infantry units conducted daily reconnaissance and reconnaissance in force operations in areas of known and suspected rocket locations. Several company and battalion size operations took place in the rocket belt during the reporting period. Their findings indicated that the rockets seem to have been fired by a few individuals utilizing commo wire at a distance of 200-700 meters from the actual launch locations ....

The report also indicated that four ambush patrols were placed to the west and east of Lai Khe each evening. During a sweep operation at one launch site, a friendly unit located one enemy KIA, one AK-47, eight flashlight batteries (wired together within a wooden framework), three improvised rocket launchers (each consisting of two 1x42 inch saplings wired together to form an X tripod), and two 122mm rockets. This finding indicated the method of operation by the enemy and the effects of counterfire.

Tan Son Nhut Air Base.

Tan Son Nhut Air Base was subjected to enemy standoff attacks by 122mm rockets on 6, 7, 8 and 10 May 1968. Each of these attacks either preceded or was in conjunction with enemy infiltration attempts and ground assault activities against the air base and adjoining areas.

The following account, extracted from the Combat Operations After Action Report of the 377th Combat Support Group, reflected basically what transpired during and following each of these attacks:

At approximately 0616, 6 May 1968, one of the air base perimeter observation towers reported incoming rockets. Two minutes later, heavy movement was reported behind the school adjacent to the south perimeter. At 0620 hours, one of the task force units charged with supporting the base was deployed to an area receiving sporadic small arms and automatic fire. Shortly thereafter, contact with an unknown size enemy unit was reported behind a school in close proximity to the base. At 0722, one of the outer perimeter bunkers reported it had made heavy contact with approximately 40 enemy adjacent to the bunker post. Contact with the enemy continued to increase. The enemy continued his attempts to infiltrate the area around the air base throughout the day using small arms sniper fire, machine gun fire and mortars to cover movement. At one time during the exchange of fire, one of the base defense sector supervisors reported observing an enemy on the roof of a building adjacent to his sector, holding an aiming stick. Permission to fire was obtained and the enemy was eliminated. The mortar barrage ceased. Sniper fire continued.

At 030310406, 7 May 1968, eleven rockets impacted on the base. Minor damage was inflicted. The impact pattern indicated that the flight line was the probable target.

At 0300, 8 May 1968, 14 122mm rockets impacted on the base. The general pattern indicated that the work areas and housing areas were the primary targets. Damage was moderate to minor.

At 0325, 10 May 1968, seven 122mm rockets impacted on the base resulting in negligible damage. This appeared to be a harassment attack.

Throughout these attacks, enemy probes and sniper fires were continuous. The reason for such action by the enemy was probably best explained by the following comments In the Combat Operations Report:

...As during the TET Offensive, the need for a free fire zone was realized. Had a free fire zone been established adjacent to the south perimeter, the enemy would have been identified earlier plus the continuous small arms fire received after 6 May would have been eliminated.


As reflected in the preceding accounts, certain Lessons learned were realized from each of the attacks;

Da Nang Air Base.

Lai Khe Base Camp.

Tan Son Nhut Air Base.

The attack on Tan Son Nhut demonstrated one of the NVA's basic tactics, that of preceding each assault on an installation with some form of standoff attack or harassment action. This complicated the problem of passive defense measures against standoff attacks considerably because of the dual requirement to provide protection for personnel on the installation, while at the same time protecting the base against enemy ground assault actions.

For this reason, installation defense preparation against standoff attacks had to take into account installation ground defense requirements. This required that the earliest pre-warning of standoff attack activity be provided all personnel, that each individual be fully trained in his duties by location, and that bunkers or shelters be located so that both requirements could be met under standoff attack conditions.



US Army Military Assistance Advisory Group Vietnam (MAAG) - Lessons Learned No. 71 Countermeasures Against Standoff Attacks (March 1969)

Secrets of the Viet Cong J W McCoy, Hippocrene Books 1992, ISBN 0-7818-0028-5

Inside the VC and the NVA Michael Lee Lanning & Dan Cragg, Ivy Books 1994, ISBN 0-8041-0500-6



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