What happened
On 8 February 1998, a Boeing 747-13 and6, registration G-BBPU, was performing a public transport flight departing from Runway 13L at J F Kennedy Airport, USA. Following lift-off, the aircraft was required to execute a low-altitude turn at 300 feet to avoid noise-sensitive areas. During this maneuver, the commander instructed the co-pilot to retract the landing gear.
When the co-pilot attempted to move the gear lever, it remained stuck in the OFF position due to an engaged lever latch. This latch is designed to prevent gear retraction until all tilt sensors confirm the main landing gear trucks have tilted correctly. Without consulting the rest of the crew or referring to the aircraft manuals, the co-pilot manually withdrew the latch and moved the lever to the UP position.
As a result, the landing gear retracted, but one gear door remained open and a red gear light stayed illuminated. The commander subsequently decided to climb to a medium altitude, jettison fuel, and return to JFK. The aircraft landed without further incident, though the landing gear bay sustained damage. There were no fatalities and no injuries among the 18 crew members and 220 passengers on board.
The investigation
The investigation established that one of the main wheel trucks had not tilted sufficiently to trigger the necessary sensors. This prevented the gear from fitting into the retraction wells properly. The investigation also looked into the crew's communication, noting that the crew were using Active Noise Reduction (ANR) headsets. It was observed that while these headsets reduce ambient noise, they can also make intercom communication more difficult.
Findings
- The co-pilot manually bypassed the safety latch mechanism to force the gear lever into the UP position.
- The manual override of the gear lever latch allowed the gear to retract while the truck was not properly tilted, leading to damage in the landing gear bay.
- The co-pilot did not consult the commander, the flight engineer, or the flight manuals before taking action.
- The use of ANR headsets may have contributed to a lack of clear communication between crew members during the critical phase of flight.