Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
The flight crew of a F28 Mark 0070 (Fokker 70) aeroplane received a MLG [main landing gear] unsafe message after landing gear down selection during approach. * * *
Inspection just after landing revealed a lot of ice near the LH (left-hand) MLG downlock actuator. * * *
Based on the quantity and location of the ice, it is considered highly likely that the ice had formed between the upper end of the downlock actuator and the upper side brace, and was accumulated during taxi on slush- and snow-contaminated taxiways and runway at the departure airport.
Ice in this location prevents the actuator from turning freely relative to the upper side brace during landing gear down selection, likely resulting in failure of the piston rod. This condition, if not corrected, could lead to further cases of MLG extension problems, possibly resulting in loss of control of the aeroplane during landing roll-out. * * * * *
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.