Pan Am Flight 816

Pan Am Flight 816
An identical Boeing 707 from Pan Am
Accident summary
Accident type	CFIT or loss of control while climbing
place	Papeete , French Polynesia
date	July 22, 1973
Fatalities	78
Survivors	1
Injured	1
Aircraft
Aircraft type	Boeing 707-321B
operator	Pan American World Airways
Mark	N417PA
Surname	Clipper Winged Racer
Departure airport	Auckland Airport , New Zealand
1. Stopover	Faa'a Airport , French Polynesia
2. Stopover	Los Angeles International Airport , United States (not reached)
Destination airport	San Francisco International Airport , United States
Passengers	69
crew	10
Lists of aviation accidents

On July 22, 1973, a Boeing 707-321B crashed on Pan-Am flight 816 shortly after take-off from Faa'a Airport . The Pan American World Airways plane crashed off the coast of Tahiti in the Pacific Ocean . 78 of the 79 occupants were killed in this most serious aircraft accident to date in French Polynesia .

Flight history

The Boeing 707 ( registration number : N417PA, c / n : 18959, s / n : 470) operated a scheduled flight from Auckland in New Zealand to San Francisco International Airport in the USA . Scheduled stopovers were planned in Papeete and Los Angeles .

Upon arrival in Papeete, a Y-shaped crack was discovered in the glass pane of the rear left cockpit window . The crew made telegraphic contact with the technical headquarters in New York , which gave permission to continue the flight. The pilots were instructed not to use the window heating. The captain decided to continue the flight to Los Angeles at a lower cruising altitude in order to keep the pressure on the damaged window low. Because this would increase fuel consumption, he ordered the aircraft to be refueled with 70,860 kg (156,220 lb ) instead of the planned 54,884 kg (121,000 lb) of kerosene .

According to the flight schedule, the departure from Papeete was scheduled for 8:30 p.m. local time. Waiting for a response from corporate headquarters and refueling delayed the departure by more than 90 minutes. At 21:52 p.m., the pilots were asked to start the engines . At 9:58 p.m., the captain asked air traffic control to allow the flight to Los Angeles at an altitude of 7,000 meters (23,000 feet ) instead of the planned 10,000 meters (33,000 feet). Appropriate route clearance has been granted. The pilots were given permission to take off at 10:04 p.m. At that time the airport was under a closed cloud cover, and it was raining. The visibility on the ground was about 8,000 meters.

The machine took off from runway 04 at 10:06 p.m. Eyewitnesses reported that the plane rose remarkably slowly. The departure procedure provided for a left turn after take-off, which the pilots initiated at an altitude of around 90 meters (300 feet). Immediately afterwards the Boeing 707 began to sink. The aircraft hit the Pacific at 10:06:45 p.m., about 30 seconds after take-off. The air traffic controller in the control tower noticed a flash of light on the sea and triggered the alarm. The site of the accident was 3.5 kilometers behind the runway threshold and about 700 meters off the coast of Papeete. Rescue workers recovered two survivors, a flight attendant and a Canadian passenger. The flight attendant died shortly afterwards from her serious injuries.

Cause of accident

Most of the debris, including both flight data recorders , sank in the sea. Despite a three-day search with sonar equipment , it was not possible to locate the wreck at a depth of 700 meters. Some floating debris was recovered, including parts of the nose landing gear and individual fragments of the fuselage, the wing structure and the horizontal stabilizer . However, the number of them was insufficient to determine the cause of the accident.

The flat climb angle after take-off seemed to indicate an engine failure, but this alone would not have led to the accident. A simultaneous failure of two engines was considered unlikely, especially since the crew had not sent an emergency call before the impact. Even after simulator tests , the French investigators found no evidence of a defect in the flight control . A break in the damaged cockpit window could not be ruled out, but the investigating commission found it doubtful. No importance was attached to the weather.

The investigators considered it possible that the pilots were distracted by an instrument or system fault and did not notice that the machine was descending. It is possible that the flight position in the captain's artificial horizon ( Attitude Direction Indicator ) was displayed incorrectly. This could have caused him to climb flatter than usual at first. When the aircraft turned left towards the open sea at a relatively low altitude in the dark, the captain lacked a visual reference point outside the cockpit in order to be able to recognize the incorrect instrument display and correct the flight attitude accordingly. Presumably the bank angle of the aircraft increased continuously after the initiation of the turn, so that it tilted over the left wing and lost altitude. The machine hit with the landing gear retracted. The buoyancy aids (flaps and slats) were still in place on impact or not yet fully retracted.

The two 59-year-old pilots had completed more than 13 hours of flight in the 48 hours before the accident and, according to the investigators, were overtired. Both pilots suffered from high blood pressure and were receiving medical treatment. The autopsied corpse of the copilot, who was one of the few victims found, also showed signs of severe arteriosclerosis .

Individual evidence

1. ↑ the NTSB states "impact on water" in its short report
2. ↑ the BEA (at that time CEA) does not specify an accident category in the final report
3. ↑ Accident Report B-707 N417PA , Aviation Safety Network (English), accessed on January 16 of 2019.
4. ↑ ^{a b c d e f} Official final report of the French commission of inquiry (PDF)
5. ↑ ^{a b c d} Aircraft Disasters, David Gero, Stuttgart 1994
6. ↑ Flight International, May 28, 1977 (PDF)

Coordinates: 17 ° 30 ′ 55 ″  S , 149 ° 34 ′ 22 ″  W