AD NUMBER: 2015-05-01

PRODUCT: All Boeing Model 757-200, -200PF,-200CB, and -300 series airplanes; and Model 767-200, -300, -300F, and -400ER series airplanes.

ACTION: Final Rule

SUMMARY: This AD was prompted by reports indicating that the counterweights in some hub assemblies of the ram air turbine (RAT) could be understrength and fracture when the RAT is rotating, and that some RAT hub assemblies were delivered with balance washer retention screws that were incorrectly heat-treated, and therefore, susceptible to fracture and cracking.

This AD requires a part number and serial number inspection to determine if certain RAT hub assemblies are installed; and, for affected RAT hub assemblies, doing an inspection for missing and fractured balance washer screws, and replacement or rework if necessary.

The FAA is issuing this AD to prevent an inoperative RAT, which, following a dual engine shutdown in flight, will cause loss of all hydraulic power to the primary flight controls, resulting in subsequent loss of control of the airplane.

DATES: This AD is effective April 20, 2015.

FMI: AD