United Airlines Flight 811

The Boeing 747 shortly after decompression ( reconstruction)

On February 24, 1989, came on board the United Airlines flight 811 (English United Airlines Flight 811 ) to an explosive decompression, were hurled through the nine passengers with their seats from the plane and torn to death.

The accident

The accident

United Airlines Flight 811 was launched on 24 February 1989 from the Los Angeles International Airport with stops in Honolulu, Hawaii, in Auckland, New Zealand and destination Sydney, Australia. On board the Boeing 747-100 with the registration number N4713U, three pilots, 15 flight attendants and 337 passengers were.

About 16 minutes after the start of the onward flight from Honolulu to Auckland and even during the climb, at an altitude of approximately 22,500 ft ( 6900 m) and a distance of about 108 km (58 nautical miles ) from Honolulu, the front cargo door suddenly opened; This resulted in a decompression of the aircraft fuselage. The hatch then tore off completely and took a part of the fuselage fairing with it, so that on the actual opening of the cargo door was still about four times four and a half meter hole in the hull. Through the resulting hole five rows of seats in Business Class were thrown off the plane, on which sat a total of nine passengers. A flight attendant, who was in the vicinity of the hole, was seriously injured.

Due to the pressure drop, the pilots initiated an emergency descent one, to get back to a level in which the oxygen partial pressure was again sufficient to prevent hypoxia. Through the decompression parts of the door had come into the engine 3, which precipitated immediately. 4 engine was also damaged and caught fire. In addition, the flaps had been damaged. Despite the damage to the hull, engines and flaps the pilot managed a safe landing in Honolulu. The passengers were evacuated without injury in 90 seconds via the emergency slides.

Cause

The incident was most likely caused by incorrect wiring, associated with poor locking mechanism of the cargo hatch, triggered. At that time, had the 747 the 100 version a small inspection window which finished flush with the cargo hatch, so that the ground crew could visually check if the bracket on the door were "locked". However, there were several deficiencies in design: You could not get close enough to the locking mechanism and not fully see. Moreover, it was the circuit that controls the power supply to the cargo hatch, defective and could cause in flight and thus open the cargo hatch. The cargo hatch that opens to the outside, was blown up by and separated from the fuselage. She tore a part of the fuselage fairing with it, making the passenger cabin was exposed in 22,500 feet altitude the air pressure prevailing there.

Cause investigation

Two parts of the cargo door were recovered from the Pacific on 26 September and 1 October 1990.

The New Zealander Lee Campbell was one of the victims of Flight 811 His parents Kevin and Susan put out an investigation to find out what was the cause of the decompression. Their research showed that a design flaw of the locking mechanism of the cargo hatch was present. Two later incidents supported the hypothesis of the Campbells:

In 1991, again to an incident at the cargo door of a Boeing 747 operated by United Airlines at New York's JFK airport. Maintenance staff was on the search for the cause for a tripped circuit breaker. During the diagnosis, there was an accidental release of the locking mechanism for the cargo hatch, making them opened. The opening of the hatch then led to similar damage as they had been found at the cargo door in flight 811.

Another disturbance in a cargo hatch of a 747 Pan American in London Heathrow prompted the manufacturer Boeing to ask all customers to correct the interference. The FAA shortened the time for the exchange of the mechanism to 30 days. Originally a deadline was provided until the next regular maintenance.

Examination results

The U.S. Transportation Security Administration was due to its investigation, a strong recommendation for all the service located Boeing 747-100 out to replace the locking mechanism by non- faulty locks. Another - not mandatory - recommendation advocated to replace all outward opening hatches through inward opening hatches, as they can not be blown out by the cabin pressure. Since this incident, there has been no more accidents 's similar to the 747-100.

In 1989, the Department was awarded a prize by the United States Secretary of Transportation. The aircraft was repaired and re-registered under the symbol N4724U. In 1990 it was put into service again. In 1997 it was sold to the Gambian Air DABIa that registered the aircraft as C5 -FBS. After the end of the Company, the aircraft was incorporated in 2000 on the Plattsburgh International Airport and cannibalized in 2004 in Plattsburgh, NY.

United Airlines took after the accident, numerous attempts to adjust to the loss of the cargo hatch R5 in the flight simulator. No crew was still following the loss of Luke able to safely land the 747.

Film and Television

• The circumstances of the accident was in the series Mayday - Alarm shown in the cockpit under the title Unlocking Disaster ( also under Explosive Evidence) in English and as Hanging by a thread on German.
• The television series The X represents the accident, led the cause, they fell to aliens.
• The fourth story in episode 17 ( 2.11) of series X-Factor: The inconceivable titled Angel uses this accident as a template for a supposedly true story.

Similar incidents

• Aloha Airlines Flight 243 - Partial loss of the body casing
• American Airlines Flight 96 - Failure of cargo hatch
• Pan Am Flight 125 - Failure of cargo hatch
• British Airways Flight 5390 - partial loss of the cockpit glazing, causing decompression
• Japan Airlines Flight 123 - Explosive Decompression by defective pressure bulkhead at the rear
• Turkish Airlines Flight 981 - Explosive Decompression by failure of a cargo door on a DC - 10 due to improper closure with subsequent crash