United Airlines Flight 811
| United Airlines Flight 811 | |
|---|---|
 The Boeing 747 before the incident |
|
| Accident summary | |
| Accident type | structural failure of the cargo door |
| place | Pacific Ocean near Honolulu , Hawaii |
| date | February 24, 1989 |
| Fatalities | 9 |
| Survivors | 346 |
| Injured | 38 |
| Aircraft | |
| Aircraft type | Boeing 747-122 |
| operator | United Airlines |
| Mark | N4713U |
| Departure airport | Los Angeles International Airport |
| Destination airport | Kingsford Smith International Airport in Sydney |
| Passengers | 337 |
| crew | 18th |
| Lists of aviation accidents | |
On February 24, 1989, on board a Boeing 747 on United Airlines Flight 811 , the failure of the front cargo hold door caused an explosive decompression , which threw nine passengers with their seats out of the aircraft and tore them to their deaths.
The accident
the accident
The United Airlines Boeing 747-122 took off on February 24, 1989 from Los Angeles International Airport with stops in Honolulu , Hawaii , Auckland , New Zealand and destination Sydney , Australia . On board the aircraft with registration number N4713U were three pilots, 15 flight attendants and 337 passengers.
About 16 minutes after take-off for the onward flight from Honolulu to Auckland and while the flight was still on the climb , at an altitude of about 22,500 ft (6900 m) and a distance of about 108 km (58 nm ) from Honolulu, the front cargo hold door suddenly opened ; this led to a decompression of the aircraft fuselage . The hatch then tore off completely and took part of the fuselage lining with it, so that a four by four and a half meter hole was created in the fuselage above the actual opening for the cargo hold door. Through the resulting hole, five rows of business class seats were thrown out of the aircraft, on which a total of nine passengers sat. A flight attendant who was near the hole was seriously injured.
Due to the pressure drop, the pilots conducted a emergency descent in order to return to a level in which the oxygen - partial pressure was sufficient to provide a hypoxia should be avoided. As a result of the decompression, parts of the door got into the engine 3, which immediately failed. Engine 4 was also damaged and caught fire. In addition, the flaps had been damaged. Despite the damage to the fuselage, engines and flaps, the pilots managed to land safely in Honolulu. The passengers were able to exit the aircraft via the evacuation slides in 90 seconds without further injuries .
root cause
The incident was most likely caused by incorrect wiring, combined with a poor locking mechanism in the cargo hatch. At that time, the version 100 747 had a small inspection window that was flush with the cargo hatch, so that the ground crew could visually check whether the door handles were in the "locked" position. However, there were several flaws in the design: You couldn't see the locking mechanism close enough or completely. In addition, the circuit that regulates the power supply to the cargo hatch was defective and could trigger in flight and thus open the cargo hatch. The cargo hatch, which opens to the outside, was blown open and separated from the hull. In the process, she tore part of the fuselage lining with her, exposing the passenger cabin to the prevailing air pressure at an altitude of 22,500 feet.
Determination of causes
Two parts of the cargo hatch were recovered from the Pacific on September 26 and October 1, 1990 .
New Zealander Lee Campbell was one of the victims. His parents Kevin and Susan Campbell did research to find out what was causing the decompression. Their research revealed that there was a design flaw in the locking mechanism of the cargo hatch. Two later incidents support the Campbell's hypothesis :
In 1991 another incident occurred in the cargo hatch of a United Airlines Boeing 747 at New York's JFK Airport . Maintenance personnel were looking for the cause of the blown fuse. During the diagnosis, the locking mechanism for the cargo hatch was unintentionally triggered, causing it to open. The opening of the hatch then resulted in similar damage as was found on the cargo door of the aircraft affected on Flight 811.
Another fault in a cargo hatch of a Pan Am 747 at London Heathrow prompted the manufacturer Boeing to ask all customers to rectify the fault. The FAA cut the time to replace the mechanism to 30 days. Originally, there was a deadline for the next regular maintenance.
Investigation results
As a result of their investigation, the US American Transport Safety Authority issued an urgent recommendation for all Boeing 747-100s in service to replace the locking mechanism with non-defective locks. Another - non-binding - recommendation was to replace all outward-opening hatches with inward-opening hatches, as these cannot be blown out by the internal pressure in the cabin. Since this incident there have been no other accidents with the 747-100.
In 1989 the crew received an award from the United States Secretary of Transportation . The aircraft was repaired and re-registered with registration number N4724U. In 1990 it was put back into service. In 1997 it was sold to the Gambian airline Air Dabia , which registered the aircraft as a C5-FBS. After the company ended, the aircraft was stored at Plattsburgh International Airport in 2000 and cannibalized in Plattsburgh , NY in 2004 .
After the accident, United Airlines made numerous attempts to recreate the loss of the R5 cargo hatch in the flight simulator . No crew was able to land the 747 safely after the hatch was lost.
Movie and TV
- The course of the accident was shown in the series Mayday - Alarm im Cockpit , Season 1, Episode 1 under the title Unlocking Disaster (also under Explosive Evidence ) in English and as a hair's breadth in German.
- The TV series The X-Files depicts the accident, but attributed the cause to extraterrestrials .
- In "Boeing 747 - The Jumbo Revolution" (original title "747: The Jumbo Revolution", GB / USA / NZ 2013) the history of the development and use of the 747 is presented, as one of the few accidents involving the 747, this is detailed
Similar incidents
Individual evidence
- ↑ Security Advisory ( Memento of 25 February 2009 at the Internet Archive ) the NTSB (Safety Recommendation A91-84 & 84) of 28 August 1991
- ^ Accident investigation report ( memento from June 6, 2010 in the Internet Archive ) of the NTSB (number AAR-92/02), short version
- ^ Honoring the Crew of United Airlines Flight 811 , House of Representatives, p. H1798, May 10, 1989, from the Library of Congress .
Web links
- Investigation report of the NTSB (AAR-92/02) (English, PDF; 3.5 MB)
- Aircraft accident data and report in the Aviation Safety Network (English)
- Copy of the Cockpit Voice Recorder
- Testimony (English)