Incident Overview
A mail flight en route from London-Gatwick Airport to East Midlands Airport experienced a catastrophic in-flight breakup during its initial descent. The aircraft's cabin attendant reported that mechanical indicators on one of the cabin doors showed an unlocked condition. Shortly thereafter, the right-hand rear door (baggage door) opened, detached from its hinge mountings, and became lodged on the leading edge of the right horizontal tailplane.
Loss of Control and Structural Failure
Following the door's displacement, the aircraft became uncontrollable and entered an increasingly steep dive. The descent culminated in several abrupt pitch oscillations. The resulting aerodynamic loads subjected both the mainplanes (wings) and the horizontal tailplanes to overstressing in upload, causing them to detach from the fuselage. The aircraft was totally destroyed.
Crew and Casualties
All three crew members on board were killed in the accident.
Probable Cause
The official investigation determined that the accident was caused by the baggage door becoming lodged on the leading edge of the right tailplane after it had opened and detached in flight. This changed the aircraft's aerodynamic characteristics, rendering it uncontrollable and leading to overstressing of the wings and tailplane, resulting in in-flight structural failure. Contributory factors included the mis-rigged state of the door operating mechanism, which allowed the top and bottom pairs of claw catches to lose synchronization, and the failure of the door warning arrangements to give adequate warning of door safety.