1975 Tân Sơn Nhứt C-5 accident

On 4 April 1975,[note 1] a Lockheed C-5A Galaxy participating in the first mission of Operation Babylift crashed on approach during an emergency landing at Tan Son Nhut Air Base, South Vietnam. The cause was ascribed to loss of flight control due to explosive decompression and structural failure. The accident marked the second operational loss and first fatal crash for the C-5 Galaxy fleet, and is the third deadliest accident involving a U.S. military aircraft after the 1968 Kham Duc C-130 shootdown and Arrow Air Flight 1285.

1975 Tân Sơn Nhứt C-5 accident
United States Air Force C-5 Galaxy, similar to the aircraft involved
Accident
DateApril 4, 1975[note 1]
SummaryExplosive decompression caused by negligent maintenance
Sitenear Tan Son Nhut Air Base, South Vietnam
Aircraft
Aircraft typeLockheed C-5A Galaxy
OperatorUnited States Air Force
Registration68-0218
Flight originTan Son Nhut Air Base
DestinationClark Air Base, Philippines
Occupants314
Passengers285
Crew29
Fatalities138[1][2][note 2]
Survivors176

Background

In early April 1975, with much of South Vietnam overrun by communist North Vietnamese forces, the administration of U.S. President Gerald Ford began instituting the evacuation of American citizens. To avoid alarming the host country, U.S. Ambassador to South Vietnam Graham Martin authorized Americans to be flown out under several conditions, one of which was Operation Babylift, in which American caregivers were paired with South Vietnamese orphans.[3]

Description

On the afternoon of Friday, 4 April 1975, C-5A, AF Ser. No. 68-0218, making the first flight of Operation Babylift, departed Tan Son Nhut Air Base for Clark Air Base in the Philippines. This first group of orphans would then transfer to charter flights and be welcomed by President Ford upon arriving in the United States at San Diego, California. At 4:15 p.m. the C-5A was over the South China Sea about 13 nautical miles (24 km) off Vũng Tàu,[4] South Vietnam, flying a heading of 136 degrees and climbing to an altitude of 23,000 ft (7,010 m). At that moment the locks on the rear loading ramp failed, causing the cargo door to open explosively. This caused explosive decompression, temporarily filling the cabin with a whirlwind of fog and debris. The blowout severed control cables to the tail, causing two of four hydraulic systems to fail, including those for the rudder and elevator,[5] and leaving the flight control with only the use of one aileron, spoilers, and power.

The pilot, Captain Dennis "Bud" Traynor, and copilot, Captain Tilford Harp, attempted to regain control of the airplane, and to perform a 180-degree turn in order to return to Tan Son Nhut.[6] The aircraft began to exhibit phugoid oscillations, but the crew countered them and maintained a controlled descent at about 250 to 260 knots (460 to 480 km/h). They were able to bring the plane to 4,000 ft (1,220 m) and begin the approach to Tan Son Nhut's runway 25L. While turning on final approach, the plane's descent rate suddenly began to increase rapidly. The crew increased power to the engines in an attempt to arrest the descent, but despite their efforts, the plane touched down at 4:45 p.m. in a rice paddy, and skidded for a quarter of a mile (400 m), became airborne again for another half-mile (800 m), crossing the Saigon River, then hit a dike and broke up into four pieces. The fuel caught fire and some of the wreckage was set ablaze.

Survivors struggled to extricate themselves from the wreckage. The crash site was in a muddy rice paddy near the Saigon River, one mile (1.6 km) from the nearest road. Fire engines could not reach the site, and helicopters had to set down some distance from the wreckage. About 100 South Vietnamese soldiers deployed around the site, which was near the site of an engagement with the Viet Cong the previous night. Out of 314 people on board, the death toll included 78 children, 35 Defence Attaché Office employees and 11 U.S. Air Force personnel; there were 176 survivors.[note 2][5] All of the surviving orphans were eventually flown to the United States. The dead orphans were cremated and were interred at the cemetery of the St. Nikolaus Catholic Church in Pattaya, Thailand.[4] The accident would also "stand as the single largest loss of life" in the Defense Intelligence Agency's history until the September 11 attacks because among the crash fatalities were five female DIA employees.[7]

Aftermath

Some members of the United States Congress called for a grounding of C-5s. In the end, the fleet was put under severe operational restrictions for several months while the cause was established. The U.S. Air Force Accident Investigation Board attributed the survival of any on board to Captain Traynor's unorthodox use of power and his decision to crash-land while the aircraft still allowed him some control. Captains Traynor and Harp, who both survived, were awarded the Air Force Cross for extraordinary valor.[8][9] Thirty-seven medals were awarded to crew members or their next of kin. USAF Flight Nurse, 1st Lieutenant Regina Aune, received the Cheney Award for 1975.[10][11]

Investigation
Rear doors of a C5 Galaxy

Given the explosive manner in which the rear doors failed, sabotage was initially suspected.[12]

Many of the components were looted from the crash site, thereby complicating the investigation; the U.S. Air Force paid a bounty for parts from the wreckage to recover them from the local populace. The United States Navy amphibious cargo ship USS Durham, frigate USS Reasoner, and command ship USS Blue Ridge were assigned to search for the flight data recorder in the South China Sea.[4] The recorder was found, and U.S. Navy ships and helicopters also discovered wreckage from the doors in the South China Sea as well as the body of a C-5 crewmember.[4]

When the rear doors were eventually recovered from the sea, investigation determined that some of the locks had not engaged properly. Maintenance records showed that locks had been cannibalized for spares, then subsequently improperly refitted so that not all the door locks were engaging correctly. Accounts also indicated the initial maintenance inspection noticed 5 of the 7 locks were not operating and failed the aircraft for flight. With external organizational pressure to get the flight airborne, a second off-shift maintenance team was called in. They subsequently missed the locks during inspection and the aircraft was cleared for flight. Furthermore, the flight crew confirmed that they had encountered difficulty closing the doors before take-off. As the air pressure differential increased with altitude, the few locks that were working correctly were unable to bear the load, and the door failed.[13]

Dramatization

The story of the disaster was featured on the seventh season of the Canadian made, internationally distributed documentary series Mayday, in the episode "Operation Babylift".

gollark: Generally speaking, probably mathematical models, but the maths involved in quantum physics and whatnot is beyond my knowledge anyway.
gollark: Also that.
gollark: ... coherent explanations? Evidence?
gollark: I have no idea how quantum entanglement is related to "strain/inertia", which are mostly macroscale concepts, and it probably isn't.
gollark: Well, that sounds nonsensical.

See also

Note
  1. The crash date is widely reported as 3 April, 4 April, and 5 April, however newspaper reports from 1975 reference a Friday afternoon crash (4 April) and an official military history dates the crash as 4 April.
  2. The number of fatalities vary depending on the source, but official accounts state 138 of 314 on board were killed.

References
  1. ASN Accident description
  2. https://www.dailyrepublic.com/projects/salute-to-travis-2014/1970s-operation-babylift-crash-brought-tragedy-hope/
  3. Nixon, Ford, and the Abandonment of South Vietnam, J. Edward Lee and Toby Haynsworth, McFarland and Company, ISBN 0-7864-1302-6, 2002.
  4. Commander in Chief Pacific Command History: Appendix III: Babylift, Carl O. Clever, CINCPAC Hawaii, 1976. The Vietnam Center and Archive, Item 2132501008, accessed 28 March 2010.
  5. "Last Flight From Saigon". USAF Southeast Asia Monograph Series. Diane Publishing. IV: 29. ISBN 1-4289-8211-6.
  6. Valor: A Galaxy of Heroes, Air Force Magazine, August 1991.
  7. Petersen, Michael B. (2012), THE VIETNAM CAULDRON: Defense Intelligence in the War for Southeast Asia (PDF), Defense Intelligence Historical Perspectives, Number 2, Defense Intelligence Agency: Historical Research Division, pp. 34–35.
  8. "Dennis W Traynor Air Force Cross". Military Times Hall of Valor.
  9. "Tilford W Harp Air Force Cross". Military Times Hall of Valor.
  10. http://www.af.mil/News/Article-Display/Article/109577/two-af-nurses-heroes-of-operation-babylift/
  11. "Colonel Regina Aune". US Air Force. Archived from the original on 12 September 2009.
  12. Patrick Mondout. "C5 Crashes in Vietnam During Operation Babylift".
  13. Lockheed C-5A Galaxy Accident description Aviation Safety Network 16 September 2017

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