Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 787-8 and 787-9 airplanes. This proposed AD was prompted by a report that some inboard and outboard trailing edge flap rotary actuators may have been assembled with an incorrect no-back brake rotor-stator stack sequence during manufacturing. This proposed AD would require an inspection of the inboard and outboard flap trailing edge rotary actuator for any discrepant rotary actuator. For discrepant rotary actuators, this proposed AD would require replacing the rotary actuator, or determining the flight cycles on the rotary actuator and doing related investigative and corrective actions if necessary. We are proposing this AD to detect and replace rotary actuators having incorrect assembly, which could cause accelerated unit wear that will eventually reduce braking performance. This degradation could lead to loss of no- back brake function and reduced controllability of the airplane.