Photo of United Airlines 747
Photo of United Airlines 747
Photo copyright Ellis M. Chernoff - used with permission
Accident Perspectives:
Airplane Life Cycle
  • Design / Manufacturing
Accident Threat CategoriesGroupings
  • Structural Failure
  • Pressurization / Decompression Failures
  • Lack of System Isolation / Segregation
  • Automation
Accident Common Themes
  • Organizational Lapses
  • Flawed Assumptions
  • Pre-existing Failures

United Airlines 811, 747-122, N4713U

Location: Honolulu, HI

Date: February 24, 1989

United Airlines (UAL) Flight 811 experienced an explosive decompression at about 22,000 feet after the forward lobe cargo door suddenly opened in flight. After the door was recovered from the bottom of the ocean, it was discovered that the cargo door latches had been powered to the nearly open position, overriding and deforming the latch sectors. The investigators determined that this powered open command most likely occurred following a normal door closure but prior to an engine start. It was concluded that this "powered open" command most likely was the result of a latent failure of a power isolation switch (S2) in combination with an electrical short in a wire harness. As a contributing factor, the NTSB cited 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 Federal Aviation Administration (FAA) following a previous door opening incident.