Incident Details
The aircraft, carrying dual registrations FAE064 and HC-BFH, experienced an accident in Ecuador several days prior to the landing at Calgary Airport. Damages to the undercarriage were reported. A ferry flight to Calgary was arranged so that technicians from De Havilland Canada could perform repairs. The flight from Quito to Calgary was completed with the undercarriage extended.
Accident Sequence
Upon touchdown on runway 28 at Calgary Airport, the nose gear collapsed. The airplane slid on its nose and came to rest, bursting into flames. Both pilots exited the cabin in a hurry and did not stop both engines. Hydraulic fluids ignited, and the aircraft was totally destroyed by fire. Both pilots were uninjured.
Investigation Findings
It was concluded that the self-centering mechanism could be forced off centre because of a system malfunction caused by the previous accident or by intentional nosewheel steering input, which would cause enough pressure to shear the pins. The internal damage to the controlcam mechanism allowed the wheels to be off centre at touchdown. Marks on the adjacent sides of the pulleys showed that the cable had been lodged in the space between the two pulleys. Although the extent of this damage was limited, it was representative of damage caused by the previous jungle accident and would have caused the sluggish response to nosewheel commands experienced earlier by the crew. When the weight of the aircraft settled on the misaligned nosewheel, the temporary ferry repairs failed in overload and the nosewheel collapsed.