A British Airways Boeing 787’s landing gear collapsed during a botched test after a short mechanic asked a taller co-worker to insert a lock-out pin into a hole he couldn’t reach – only for the second mechanic to put it in the wrong place.
The Laurel and Hardy-style failure was detailed in a bulletin from Britain’s Air Accidents Investigation Branch (AAIB), explaining why the 787’s nose landing gear (NLG) was accidentally retracted during maintenance at Heathrow Airport in June.
“To prevent the landing gear from retracting, the procedure required pins to be inserted in the nose and main landing gear downlocks. However, the NLG downlock pin was installed in the NLG downlock apex pin bore which was adjacent to the correct location to install the downlock pin,” said the AAIB in its report.
British Airways Boeing 787 G-ZBJB after the nose landing gear retraction accident (Crown Copyright/AAIB/licensed under OGL)
The 787, G-ZBJB, was scheduled to operate a cargo flight on 18 June. When its pilots arrived early that morning they found ground engineers already working on the aircraft, pushing back its scheduled departure by 40 minutes.
Engineers were trying to clear error messages in the 787’s onboard fault recording system about one of the NLG’s door-closed solenoid valves. Clearing the message involved fitting lock-out pins to the airliner’s undercarriage to prevent it from moving, starting the hydraulic pumps and cycling the gear lever in the cockpit up and down. Without the pins, the landing gear would retract.
Unfortunately for British Airways, a Laurel and Hardy moment resulted in a very expensive blunder when the NLG unexpectedly retracted during the procedure. Two mechanics were sent to fit the downlock pins to the landing gear before confirming to a colleague in the cockpit that the gear was ready.
“As [Mechanic] 1 was not tall enough to reach the NLG locking pin hole without steps,…