An Australian Transport Safety Bureau (ATSB) investigation has found the has discovered the
issue that prevented the main landing gear of a Qantas Boeing 787-9 from retracting
after takeoff. The aircraft, VH-ZNH, was operating QF645 from Sydney to Perth on Monday, June 21st
when the incident took place. Let’s take a look at the investigation findings...
On the day of the incident, the aircraft took off and the pilots selected UP on the aircraft’s
landing gear lever. However, they received a warning that neither main landing gear had
retracted to the ‘up and locked’ position. With checklists unable to resolve the issue,
the pilots then selected the landing gear lever to DOWN. There was a positive gear
extension indication, and the aircraft returned to Sydney for a safe landing.
A subsequent ATSB investigation found two of five landing gear downlock pins were not
removed after the aircraft before departure. Further, pins were also
not identified during subsequent preflight inspections. In a statement, the ATSB said:
“Pins are inserted into the nose and main landing gear when the aircraft is
on the ground to prevent inadvertent gear retraction during maintenance or towing,”
“In this case, two of the pins, one of the two for each main landing gear, had not been
removed after towing and prior to the flight. In addition, subsequent preflight inspections by the
flight and dispatch crew did not identify that the pins remained in place prior to departure.”
Locking a plane’s landing gear in place when aircraft are on the ground,
downlock pins prevent the downlock strut from folding
and are manually installed after an aircraft arrives at the gate or other parking spot.
Downlock pins should have streamers attached to them, serving as a visual prompt. In this case,
red-colored ‘remove before flight’ tags were attached to the Dreamliner.
According to the ATSB investigation the senior ground crew member looking after the jet removed
the nose gear downlock pin, then walked to the aircraft’s rear and removed one gear pin from
the right main gear. At the same time, one of the wing walkers removed a gear pin from the left main
gear. Neither the senior ground crew member nor the wing walker had towed a 787 before.
On the plane was a licensed 787 aircraft maintenance engineer (L.A.M.E.), in the
role of flight deck operator and an aircraft maintenance engineer (A.M.E.). What followed
was a combination of miscommunication, misunderstanding, and inexperience.
There’s a long sequence of events that led to the incident- something explained in full
detail on SimpleFlying.com. However, here is a simmary of where things went wrong:
Both team members reportedly did not identify any streamers associated with the gear pins.
The LAME’s ladder was not high enough to see into the pin stowage location.
Instead of visually checking the number of pins stowed, he felt around and physically
identified pin stowage holes, and stowed the three downlock pins he had.
Also having issues with the ladder’s height, the AME couldn’t see into the stowage location either.
Reaching in, he felt the downlock pins there. Relying on the LAME and AME endorsements in
the technical logs, the Captain and First Officer noted that the
gear pins had been removed and stowed. The Second Captain conducted an external
inspection and did not identify the two remaining downlock pins.
A Swissport supervisor conducting a final check also did not notice the remaining downlock pins.
The ATSB suspects that the missed gear pin streamers may have been stuck
on the gear from a combination of grime and recent wet and windy conditions.
The post-incident inspection found all four main gear pins’ streamers to be in place,
but dull and frayed. Their condition before the flight could not be conclusively determined.
“‘Remove before flight’ streamers are visual reminders to remove covers and lockout devices
prior to flight, but can be subject to varying environmental conditions that can reduce
their visibility,” ATSB Director Transport Safety Stuart Macleod said in a statement.
“Expectation can also affect your ability to identify these warning devices.
If you are not expecting to see a ‘remove before flight’ streamer,
you are significantly less likely to detect one that is present.
“The same principle can also prevent the discovery of damaged and/or missing components.”
What are your thoughts on this incident? We’d love to hear about them in the comments section!