AD NUMBER: 2008-11-12
MANUFACTURER: Fokker
SUBJECT: Airworthiness Directive 2008-11-12
SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This 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: To date, there have been at least 10 reported events on Fokker 70 (F28 Mark 0070) and Fokker 100 (F28 Mark 0100) aircraft where the flight crew manually overpowered the autopilot, inadvertently neglecting to disengage the autopilot. * * *When the autopilot is not disengaged, the elevator servo motor is overpowered and the horizontal stabilizer is moved by the Automatic Flight Control & Augmentation System (AFCAS) auto-trim in a direction opposite to the (manual) deflection of the elevator, causing high elevator control forces. This condition, if not corrected, could cause the stabilizer to move to an extreme out-of trim position, creating the (remote) possibility of loss of control of the aircraft, due to the extreme control loads. We are issuing this AD to require actions to correct the unsafe condition on these products.

FMI: www.faa.gov/regulations_policies/airworthiness_directives/