What happened
On 25 November 1998, a Boeing 767-31K, registration G-DIMB, arrived at Manchester International Airport following a passenger flight from Las Vegas. Upon arrival, ground handlers discovered that at least two LD2 baggage containers had shifted within the rear hold during the flight, becoming jammed in the doorway area. The movement of these containers was severe enough that one had punctured the hold ceiling, resulting in structural damage to the cabin floor beam above.
During the flight, cabin crew in the rear of the aircraft reported hearing a 'thould' during takeoff, though they initially believed the noise was caused by a toilet compartment door swinging open. Some passengers also noted a noise but were informed it was merely turbulence. There were no fatalities and no injuries to the 11 crew members or 318 passengers on board.
The investigation
An investigation by the AAIB, supported by the NTSB in the United States, examined the loading procedures and the physical damage to the aircraft. The inspection revealed that a 1.5-metre section of the cabin floor support beam had buckled and fractured. This impact also damaged the insulation of a standby power system cable, leading to evidence of electrical arcing. Additionally, several motorised guide stops in the doorway roller mat were broken due to being struck by the moving containers.
Investigators determined that the lateral guide stops, which are designed to prevent the rearward movement of containers, had been manually retracted and latched. This occurred because the ground crew in Las Vegas had encountered difficulties unloading the aircraft on its previous leg and had manually locked the stops to facilitate offloading. A shift change occurred before the return flight was loaded, and the incoming staff were not informed that the stops had been manually retracted. Consequently, the stops failed to extend automatically, and the error went unnoticed when the baggage door was closed.
Findings
- The primary cause of the incident was the failure to extend the lateral guide stops to their correct position prior to departure.
- A lack of communication during a shift change at the departure airport meant the incoming loading crew was unaware the stops had been manually locked in the retracted position.
- The containers were able to roll backward unimpeded during the aircraft's rotation at takeoff because the stops were not engaged.
- The containers on the right side of the hold struck the doorway guide stops, causing them to break and allowing the containers to 'jump' the rear stops and impact the floor structure.
- The damage to the standby power system cable created a potential fire risk due to electrical arcing near the APU fuel line.
Safety action
- Recommendation 99-6: The FAA and the aircraft manufacturer should consider modifications to the standby system power cable and adjacent fuel supply line at the station 1351 floor beam on the left side of the rear hold of Boeing 767 aircraft to mitigate the risk of impact damage and subsequent fire.
- Recommendation 99-7: The FAA and the aircraft manufacturer should consider implementing a warning system or an interlocking mechanism between the retractable stops and the baggage door closure system to prevent the door from being closed if the stops are incorrectly set.