1989 – Feb 24, cargo door fails/explosive decompress., United 811, leaving Honolulu, HI– 9

–9 NTSB. AAR. Explosive Decompression–Loss of Cargo Door in Flight, United…811…1989. 1992, p.v.
–9 Orange County Register, Santa Ana, CA. “Jumbo Jet Rips Open.” 2-25-1989, p. A24.

Narrative Information

NTSB: “Executive Summary

“On February 24, 1989, United Airlines flight 8111, a Boeing 747-122, experienced an explosive decompression as it was climbing between 22,000 and 23,000 feet after taking off from Honolulu, Hawaii, en route to Sydney, Australia with 3 flightcrew, 15 flight attendants, and 337 passengers aboard.

“The airplane made a successful emergency landing at Honolulu and the occupants evacuated the airplane. Examination of the airplane revealed that the forward lower lobe cargo door had separated in flight and had caused extensive damage to the fuselage and cabin structure adjacent to the door. Nine of the passengers had been ejected from the airplane and lost at sea.

“A year after the accident, the Safety Board was uncertain that the cargo door would be located and recovered from the Pacific Ocean. The Safety Board decided to proceed with a final report based on the available evidence without the benefit of an actual examination of the door mechanism. The original report was adopted by the Safety Board on April 16, 1990, as NTSB/AAR-90/01.

“Subsequently, on July 22, 1990, a search and recovery operation was begun by the U.S. Navy with the cost shared by the Safety Board, the Federal Aviation Administration, Boeing Aircraft Company, and United Airlines. The search and recovery effort was supported by Navy radar data on the separated cargo door, underwater sonar equipment, and a manned submersible vehicle. The effort was successful, and the cargo door was recovered in two pieces from the ocean floor at a depth of 14,200 feet on September 26 and October 1, 1990.

“Before the recovery of the cargo door, the Safety Board believed that the door locking mechanisms had sustained damage in service prior to the accident flight to the extent that the door could have been closed and appeared to have been locked, when in fact the door was not fully latched. This belief was expressed in the report and was supported by the evidence available at the time. However, upon examination of the door, the damage to the locking mechanism did not support this hypothesis. Rather, the evidence indicated that the latch cams had been back-driven from the closed position into a nearly open position after the door had been closed and locked. The latch cams had been driven into the lock sectors that deformed so that they failed to prevent the back-driving.

“Thus, as a result of the recovery and examination of the cargo door, the Safety Board’s analysis and probable cause have been modified. This report incorporates these changes and supersedes NTSB/AAR-90/091.

“The issues in this investigation centered around the design and certification of the B-747 cargo doors, the operation and maintenance to assure the continuing airworthiness of the doors, cabin safety, and emergency response.

“The National Transportation Safety Board determines that the probable cause of this accident was the sudden opening of the forward lower lobe cargo door in flight and the subsequent explosive decompression. The door opening was attributed to a faulty switch or wiring in the door control system which permitted electrical actuation of the door latches toward the unlatched position after initial door closure and before takeoff. Contributing to the cause of the accident was aa deficiency in the design of the cargo door locking mechanisms, which made them susceptible to deformation, allowing the door to become unlatched after being properly latched and locked. Also contributing to the accident was a lack of timely corrective actions by Boeing and the FAA following a 1987 cargo door opening incident on a Pan Am B.747.

“As a result of this investigation, the Safety Board issued safety recommendations concerning cargo doors and other non-plug doors on pressurized transport category airplanes, cabin safety, and emergency response.” (pp. v-vi.)

Newspaper

Feb 24: “Passengers aboard United Airlines Flight 811 nestled in their seats, settling down for the nearly nine-hour, pre-dawn trip Friday from Honolulu to Auckland, New Zealand. A flight attendant announced that the crew would begin serving drinks. The jumbo jet was flying about 20,000 feet above the Pacific Ocean. It was 2:15 a.m.

“Passengers suddenly heard a hissing sound and a roar. Then they saw the sky. As they watched, horrified, a huge hope opened in a forward, right-side wall. Nine people in three rows instantly were sucked through the hole, apparently to their deaths. Pieces of the plane peeled away and the cabin became a wind tunnel for debris and dust. One engine quit. Another caught fire. The crippled airliner plunged to 4,000 feet. ‘All of a sudden it was like a dream – a section of the plane wasn’t there any longer,’ Gary Garber said in a telephone interview from the emergency room of a Honolulu hospital. ‘We heard a hissing noise and then noise from the explosion, if you want to call it that. Then we put our heads down. A moment later, we put our heads up and I could see where the seats used to be and the people weren’t there,’ said Garber, of Tarzana….

“About 15 minutes later, the plane neared Honolulu….” (Orange County Register, Santa Ana, CA. “Jumbo Jet Rips Open.” 2-25-1989, p. A24.)

Sources

National Transportation Safety Board. Aircraft Accident Report. Explosive Decompression—Loss of Cargo Door in Flight, United Airlines Flight 811, Boeing 747-122, N4713U, Honolulu, Hawaii, February 24, 1989. Washington, DC: NTSB, 3-18-1992, 121 pages. Accessed 12-6-2021 at: https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9202.pdf

Orange County Register, Santa Ana, CA. “Jumbo Jet Rips Open.” 2-25-1989, p. A24. Accessed 12-6-2021 at: https://newspaperarchive.com/santa-ana-orange-county-register-feb-25-1989-p-33/