HONOLULU, HI, USA
N4713U
BOEING 747-122
The Safety Board's full report on this investigation is provided as Aviation Accident Report number AAR-92/02. To obtain a copy of this report, or to view the executive summary online, please see the Web site at http://www.ntsb.gov/publictn/publictn.htm FTL #811 WAS A SCHEDULED PASSENGER FLIGHT FROM LOS ANGELES TO SYDNEY, AUSTRALIA, WITH STOPS IN HONOLULU (HNL), HI, AND AUCKLAND, NEW ZEALAND. THE FLT WAS UNEVENTFUL UNTIL AFTER DEPARTURE FROM HNL. WHILE CLIMBING FROM FL220 TO FL230 THE CREW HEARD A 'THUMP' FOLLOWED BY AN EXPLOSION. AN EXPLOSIVE DECOMPRESSION WAS EXPERIENCED AND THE #3 AND #4 ENGS WERE SHUTDOWN BECAUSE OF FOD. THE FLT RETURNED TO HNL AND PASSENGERS WERE EVACUATED. INSPECTION REVEALED THE FORWARD LOWER LOBE CARGO DOOR DEPARTED INFLT CAUSING EXTENSIVE DAMAGE TO THE FUSELAGE AND CABIN ADJACENT TO THE DOOR. NINE PASSENGERS WERE EJECTED AND LOST AT SEA. INVESTIGATION CENTERED AROUND DESIGN AND CERTIFICATION OF THE DOOR WHICH ALLOWED IT TO BE IMPROPERLY LATCHED, AND THE OPERATION AND MAINTENANCE TO ASSURE AIRWORTHINESS OF THE DOOR AND LATCHING MECHANISM. (SEE NTSB/AAR-90/01)
THE SUDDEN OPENING OF THE IMPROPERLY LATCHED FORWARD LOBE CARGO DOOR IN FLIGHT AND THE SUBSEQUENT EXPLOSIVE DECOMPRESSION. CONTRIBUTING TO THE ACCIDENT WAS A DEFICIENCY IN THE DESIGN OF THE CARGO DOOR LOCKING MECHANISMS, WHICH MADE THEM SUSCEPTIBLE TO INSERVICE DAMAGE, AND WHICH ALOWED THE DOOR TO BE UNATCHED, YET TO SHOW A PROPERLY LATCHED AND LOCKED POSITION. ALSO CONTRIBUTING TO THE ACCIDENT WAS THE LACK OF PROPER MAINTENANCE AND INSPECTION OF THE CARGO DOOR BY UNITED AIRLINES, AND A LACK OF TIMELY CORRECTIVE ACTIONS BY BOEING AND THE FAA FOLLOWING A PREVIOUS DOOR OPENING INCIDENT.
Source: NTSB Aviation Accident Database
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