Incident Overview
Description
When the DHC-5D Buffalo touched down on runway 28 at Calgary International Airport, AB (YYC), the nosegear collapsed. Hydraulic fluid ignited and the aircraft burned out. The aircraft was operating on a ferry flight from Quito, Ecuador to Calgary, Canada for repairs. Due to a previous accident the landing gear remained down during the ferry flight. 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.
Primary Cause
Self-centering mechanism malfunction due to a previous accident or intentional steering input.Self-centering mechanism malfunction due to a previous accident or intentional steering input.Share on:
