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:
When preparing for landing, the flight crew of a F28 Mark 0100 (Fokker 100) aeroplane observed a main landing gear (MLG) unsafe indication after landing gear down selection. * * * [T]he right (RH) MLG was partly extended and the left (LH) MLG door was open but without the MLG being extended. * * * Subsequent investigation revealed that the cause of the MLG extension problem was the (partially) blocked hydraulic return line from the MLG selector valve by pieces of hard plastic. These were identified as parts of the poppet seat of PBSOV [parking brake shut- off valve] Part Number (P/N) 70379. * * * This condition, if not detected and corrected, could lead to further events where the MLG fails to extend, possibly resulting in loss of control of the aeroplane during landing. * * * * * The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.