Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all The Boeing Company Model 787-8, 787-9, and 787-10 airplanes. This proposed AD was prompted by reports of ram air turbine (RAT) pump barrel assembly failures, which caused the RAT to fail to provide hydraulic power. The failures were determined to be caused by variations in the bronze metal used during manufacturing, which can result in varying fatigue properties. This proposed AD would require an inspection or records review to determine the part number of the RAT pump and control module (PCM) and of the RAT assembly, and replacement of any RAT PCM or any RAT assembly having certain part numbers. This proposed AD would also prohibit the installation of affected parts. The FAA is proposing this AD to address the unsafe condition on these products.