United Airlines Flight 811
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 The damage on United Airlines Flight 811 |
|
| Summary | |
|---|---|
| Date | February 24, 1989 |
| Type | explosive decompression |
| Site | Pacific Ocean near Honolulu, Hawaii |
| Fatalities | 9 |
| Injuries | 38 |
| Aircraft | |
| Aircraft type | Boeing 747-122 |
| Operator | United Airlines |
| Tail number | N4713U |
| Passengers | 337 |
| Crew | 18 |
| Survivors | 346 |
United Airlines Flight 811 experienced an explosive decompression on Friday, February 24, 1989 after take-off from Honolulu International Airport, Honolulu, Hawaii. The explosion, caused by a malfunctioning cargo door that opened during flight, ripped out several rows of seats containing 9 passengers, who were killed.
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[edit] Incident
United Airlines Flight 811, a Boeing 747-122 (registration number N4713U), took off from Honolulu International Airport bound for Sydney, Australia, via Auckland, New Zealand with 3 flight crew, 15 flight attendants, and 337 passengers aboard.
As the 747 climbed to between 22,000 and 23,000 feet the R5 cargo door tore open, decompressing the cabin and leaving a gaping hole. Five rows of business class seats were blown out of the aircraft, along with nine passengers. A flight attendant, lying down beside the hole caused by the decompression, was severely injured.
Because the cabin was no longer pressurized, the pilots initiated an emergency descent to reach an altitude with breathable air. The explosion had knocked out the number three engine and the number four engine caught fire. Despite only partial flaps (a portion of the shed fuselage damaged the flaps on one wing) and concerns over the plane's landing gear and structural integrity, the crew made a perfect landing and deployed all ten evacuation slides on the aircraft. The evacuation was completed in 90 seconds, with no additional injuries occurring.
[edit] Cause
The incident was most likely caused by both improper wiring and a poor latching mechanism in the R5 cargo door. At the time, the design of the 747-122 provided a small window situated flush against each of the cargo doors, so that the ground crew could visually confirm that the doors' latches were set to the locked position. There were, however, several flaws in this design. It didn't allow a particularly close look at the door latches, and it didn't show the entire latching mechanism, which made the complete inspection of the latched door impossible. Furthermore the circuit controlling electrical power to the doors was faulty and could operate in flight, which caused the doors to unlock. The R5 door, being an outward-opener, blew open and separated from the fuselage. It took a large section of the aircraft's fuselage with it, leaving the passenger cabin exposed to the elements at 22,000 feet. At this point the aircraft was approximately 60 miles from Honolulu. It managed to make a safe turnaround and a safe landing, after which an evacuation was immediately carried out.
[edit] Personal investigation
Lee Campbell was one of the casualties on flight 811. He was a New Zealander who was returning home to New Zealand. After his death, Lee Campbell's parents Kevin and Susan personally pursued an investigation to find out what really went wrong with the plane's engineering. Their investigation led them to conclude that the design of the aircraft's cargo door latching mechanism had been flawed.
In 1991, an incident[1] involving malfunction of a UAL Boeing 747 cargo door occurred at New York's JFK airport. At the time, United Airlines maintenance staff were investigating the cause of a circuit breaker trip. In the process of diagnosing the cause, an inadvertent operation of the electric door latch mechanism caused the cargo door to open spontaneously. This incident led to latch damage similar to that observed on the flight 811 cargo door. Two pieces of the flight 811 cargo door were recovered from the Pacific ocean on 26 September 1990 and 1 October 1990.
The Campbell's investigation and hypothesis subsequently gained more credibility.
Sydney based clinical pharmacologist Dr Michael Crawford was another casualty of flight 811. His Canberra based wife Jill and then adult children Meg, James and Katherine were unaware for some time that Michael had been transferred from an earlier direct flight onto the doomed flight. Michael's body was never retrieved. The Crawford family are grateful for the work of the Campbell's and pleased that the crew of the flight received recognition for their heroic response to the disaster and that no further lives were lost.
[edit] Result
The NTSB issued an emergency recommendation for all 747-100s in service at the time to replace their cargo door latching mechanisms with new, non-faulty locks.[2] A subrecommendation suggested replacing all outward-opening doors with inward-opening doors, which cannot open in flight due to the pressure differential. No similar accidents have occurred on 747-100s since this accident.
In 1989, the flight crew (none of whom were ejected during the explosion) received the Secretary's Award for Heroism for their actions.[3] The aircraft was successfully repaired, re-registered as N4724U, and returned to service in 1990.
United Airlines ran a simulation through a flight simulator and were, despite many attempts and variable tweaks, unable to successfully land a plane after losing the R5 door.
[edit] In Pop Culture
- A fictionalized version of the accident, suggesting alien involvement, was portrayed in the TV show The X-Files.
- The accident was featured in the episode Unlocking Disaster (also known as Explosive Evidence) from Air Crash Investigation.
[edit] See also
- Aloha Airlines Flight 243 - suffered explosive decompression causing the roof to blow off.
- American Airlines Flight 96 - cargo door failure.
- Pan Am Flight 125 - cargo door failure.
- British Airways Flight 5390 - fauty maintenance on the cockpit window causing blow out of window.
- Japan Airlines Flight 123 - explosive decompression in the tail section, causing loss of control and a crash into Mt. Osutaka.
[edit] References
- ^ NTSB Safety Recommendation A91-84 & 84, 28 August 1991
- ^ Aircraft Accident Report Number AAR-92/02 Executive Summary, National Transportation Safety Board.
- ^ Honoring the Crew of United Airlines Flight 811, House of Representatives, Page H1798, May 10, 1989, Retrieved from the Library of Congress.
