Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 787-8 and 787-9 airplanes. This proposed AD was prompted by a report that the Parking Brake and Alternate Pitch Trim Module (PBM) may unintentionally disengage, fail to set, fail to release, or become jammed. This proposed AD would require replacing the PBM and doing a PBM installation test. We are proposing this AD to address the unsafe condition on these products.