Federal Aviation Administration October 20, 2010 – Federal Register Recent Federal Regulation Documents

The FAA proposes to adopt a new airworthiness directive (AD) for GE CF6-45 and CF6-50 series turbofan engines. This proposed AD would require performing a fluorescent penetrant inspection (FPI) of the stage 3 low-pressure turbine (LPT) rotor at every shop visit at which the LPT module is separated from the engine. This proposed AD results from seven reports of uncontained failures of LPT stage 3 disks and eight reports of cracked LPT stage 3 disks found during shop visit inspections. We are proposing this AD to prevent LPT rotor separation, which could result in an uncontained engine failure and damage to the airplane.

We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires repetitive inspections for fatigue cracking and corrosion of the upper link fuse pin of the nacelle struts, and related investigative and corrective actions if necessary. The existing AD also provides terminating action for the repetitive inspections. This AD revises certain criteria for the terminating action. This AD was prompted by two reports of cracked upper link fuse pins. We are issuing this AD to prevent fatigue cracking or corrosion of the upper link fuse pin, which could result in failure of the fuse pin and consequent reduced structural integrity of the nacelle strut and possible separation of the strut and engine from the airplane during flight.