In 1971 British European Airways Flight 706 crashed in Belgium , killing all 63 on board ; the cause was determined to be corrosion of the rear pressure bulkhead by fluid contamination , perhaps from the lavatory . The corrosion was not detectable by the inspection techniques at the time . In 1985 Japan Airlines Flight 123 crashed after a catastrophic failure of the aft pressure bulkhead . The failure occurred due to faulty repair of the bulkhead after a tailstrike seven years earlier , when a single repair patch plate was incorrectly cut in two " to make it fit " . Failure of the bulkhead damaged hydraulic pipes passing through . Boeing later calculated that the incorrect installation would be expected to fail after approximately 10,000 pressurizations ; the repaired aircraft accomplished 12,318 successful flights before the crash
British European Airways Flight 706
British European Airways Flight 706
Aft pressure bulkhead