Investigation Summary
The accident occurred during a night mail flight operated on behalf of the Royal Mail. As the aircraft was descending toward East Midlands Airport, the postal assistant in the cabin reported that a door indicator was showing an unlocked status. Shortly after, the right-hand rear baggage door opened and was torn from its hinges by the slipstream. Instead of falling away, the door struck and became wedged onto the right horizontal stabilizer. This caused an immediate and massive change in the aircraft's pitch characteristics. The pilots declared a Mayday, reporting severe control problems and the suspected loss of the rear door. As the crew struggled to maintain control, the aircraft entered a series of violent pitch oscillations. The upward aerodynamic forces generated during these maneuvers overstressed the airframe, leading to the simultaneous failure and detachment of both wings and the tailplane. The fuselage crashed into fields near Nailstone.
Final Conclusions
The investigation by the AAIB concluded that the primary cause was the baggage door becoming lodged on the right tailplane, rendering the aircraft uncontrollable. The door failure was attributed to a mis-rigged operating mechanism where the top and bottom pairs of claw catches had lost synchronization, allowing the door to open under pressurization despite appearing closed. Contributory factors included the design of the door warning system, which failed to provide the crew with sufficient time to intervene before the door failed completely.
Video Analysis
Dan-Air Flight 240 | Wikipedia audio article — An overview of the 1981 accident involving a Hawker Siddeley HS 748 that suffered structural failure due to a cabin door detachment.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
First Officer
Systems & Failure Modes
Baggage Door Latching Mechanism
A mechanical system using claw catches to secure the door; mis-rigging caused the top and bottom catches to lose synchronization, allowing the door to open under pressure.
Door Warning Indicators
Mechanical indicators designed to show the lock status of the doors; the system failed to provide adequate advance warning to the crew.
Horizontal Tailplane
The primary pitch control surface; its aerodynamic function was compromised when the detached door became lodged on its leading edge.
Interesting Facts
- 01The aircraft was a Hawker Siddeley HS 748, also known as the Avro 748.
- 02The flight was a dedicated mail run carrying no passengers, only two pilots and one postal assistant.
- 03The aircraft had accumulated 34,592 flying hours at the time of the accident.
- 04The baggage door was found wedged on the leading edge of the right horizontal stabilizer.
- 05Witnesses observed the aircraft's wings fold upward and detach before the fuselage hit the ground.
Safety Actions & Advisories
Door Rigging Procedures
The investigation led to a review of maintenance and rigging procedures for HS 748 door mechanisms to ensure synchronization of locking claws.