Pan Am Flight 526A
| Pan Am Flight 526A | |
|---|---|
 A structurally identical Douglas DC-4 in the painting of the Pan Am at the time |
|
| Accident summary | |
| Accident type | Ditching |
| place | Atlantic Ocean , about 18 km northwest of San Juan |
| date | April 11, 1952 |
| Fatalities | 52 |
| Survivors | 17th |
| Aircraft | |
| Aircraft type | Douglas DC-4 |
| operator | Pan American World Airways |
| Mark | N88899 |
| Surname | Clipper Endeavor |
| Departure airport | Isla Grande Airport , San Juan , Puerto Rico |
| Destination airport | Idlewild Airport , New York , United States |
| Passengers | 64 |
| crew | 5 |
| Lists of aviation accidents | |
On April 11, 1952, the crew of a led Douglas DC-4 on the Pan Am Flight 526A from San Juan to New York a ditching through after an engine had failed and a second only supplied a reduced power. The plane touched down off the coast of Puerto Rico in heavy seas and sank after three minutes. In the accident, 52 of the 69 occupants were killed.
plane
The Douglas DC-4 Clipper Endeavor ( registration number : N88899, c / n : 10503) was one of 120 C-54B-1-DC ( USAAF serial no .: 42-72398) built and used as a military transporter . The machine was after reconstruction in a civilian airliner on 10 August 1946 the airline Pan American World Airways handed and had until the occurrence of the accident completed 20,835 flight hours.
Flight history
The Douglas DC-4 took off at 12:11 p.m. local time from Isla Grande Airport , the then international airport in San Juan , on an eight-hour scheduled flight to New York . After retracting the starting flaps and the landing gear , the crew routinely reduced the engine power. The copilot noticed a rapid drop in oil pressure in engine no. 3 (inner right engine) and a constant increase in oil temperature. The captain decided to abort the flight and at 12:13 p.m. informed the air traffic controller that he would be returning to San Juan. The crew then initiated a wide left turn.
The defective engine was stopped at an altitude of around 100 meters (350 feet ) and its propeller was brought into the aerodynamically neutral sail position. At the same time, the pilots increased the performance of the other three engines in order to gain a sufficient safety altitude. The first, temporary misfires occurred in engine no. 4 (far right). At an altitude of just under 170 meters (550 feet), this engine began to run increasingly rough and lose power after repeated misfires. The crew tried to continue the climb, the speed steadily decreasing. As a result of the loss of speed, the aircraft's angle of attack increased continuously. At the same time it lost height. After the pilots reported at 12:17 p.m. that they were still a considerable distance from the airport, the air traffic controller alerted the local rescue center of the United States Coast Guard .
Because the captain feared that the machine could hit the reefs off the coast, he changed course in a westerly direction. At the same time, the emergency drain valves of the fuel tanks were opened and the power of the two left engines increased ( take-off power ). The flight engineer rushed into the cabin and informed the passengers that a ditching was imminent. The plane touched down at 12:20 p.m. about seven kilometers off the north coast of Puerto Rico in the Atlantic , with the tail section of the plane breaking off. The wave height in the sea area was between three and five meters.
An orderly evacuation did not take place. The flight attendants called out to the passengers that the life jackets were in the backrests of the seats, but not how they should be put on and operated. Many passengers refused to leave the plane. Due to the heavy swell, the cabin filled very quickly with water, which flowed in through the open front outer door, through the emergency exits above the left wing and the broken rear fuselage. The second officer managed to lower a life raft into the water, which he, the two flight attendants and five passengers boarded. Attempts by the first officer to pull more rafts from the stowage compartment in the rear of the cockpit together with a female passenger failed, whereupon both of them escaped through a cockpit window to safety. The captain fell overboard when he opened the outer door, which had been slammed by a wave. The plane went down about three minutes after touchdown. In addition to the five crew members, only twelve passengers survived the accident.
Cause of accident
Faults occurred in engine no.3 on the outbound flight the day before. During the subsequent maintenance in San Juan, metal shavings were found in the front part of the engine (" nose section "), in the oil strainer and in the oil pan . The mechanics telegraphed the technical center in Miami about the damage and the planned repair, but received no feedback. Components of the engine were replaced and the engine oil changed without finding the actual cause of the metal abrasion. Neither the repair carried out nor the subsequent test run of the engine met the standards the company had set for this type of damage. For example, the engine should have been filled with only 10 gallons of engine oil for the first test run in order to achieve efficient cleaning of the oil system. According to the investigators, the machine was in a non- airworthy condition at departure .
In addition, there were omissions on the part of the crew. Test flights showed that the DC-4 was able to maintain its altitude even after a one-sided failure of two engines. Probably the out-of-round running engine no. 4 also developed a considerable thrust, so that the machine hardly yawed to the right after the failure of the inner right engine despite unchanged trim . The pilots made the mistake of continuing the climb without fully utilizing the available power of the three engines. Due to the increasing loss of speed, the angle of attack increased, so that the aircraft lost altitude with its "nose raised". When the master increased the engine power to " take-off power " shortly before ditching , it was probably no longer possible to prevent the impact because of the high angle of attack and the low flight altitude.
The aircraft's tail hit the surface of the water first, causing the rear fuselage section to break off at the height of the cabin rear wall. All occupants survived the impact without serious injuries. Between the announcement and execution of the ditching, the flight attendants did not have enough time to familiarize the passengers with the life jackets and prepare for the evacuation, which led to the high number of fatalities.
Consequences
The US Civil Aeronautics Board (now the National Transportation Safety Board ) issued new regulations after the accident to speed up evacuations and reduce the number of victims in future ditchings. These specifications were adopted internationally and are still valid today. It was stipulated, among other things, that ...
- the cabin crew must point out the location of the emergency exits before departure.
- Passengers on flights which will be over water for a long time must be informed before take-off about where to find the life jackets and how to use them.
- Liferafts or life rafts are to be easily accessible and distributed on board.
Individual evidence
- ^ René J. Francillon: McDonnell Douglas Aircraft since 1920 , p. 665
- ^ REG Davies: PAN AM An Airline and its Aircraft , Hamlyn, 1987, p. 52
- ↑ a b c d e f g h i Civil Aeronautics Board, Pan American World Airways Inc. - San Juan, Puerto Rico, April 11, 1952
- ↑ a b c Aircraft disasters, David Gero, Stuttgart 1994
Coordinates: 18 ° 32 ′ 6 ″ N , 66 ° 15 ′ 5 ″ W.