Federal Aviation Administration May 25, 2012 – Federal Register Recent Federal Regulation Documents

We are superseding an existing airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. This new AD continues to require initial inspections, adds additional inspections, and a mandatory terminating action. This AD was prompted by additional cracking on RB211-Trent 700 and RB211-Trent 800 IP compressor rotor shafts found since the existing AD was issued. We are issuing this AD to detect cracking on the IP compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (BHTC) Model 427 helicopters which requires replacing certain tailboom attachment hardware and at certain intervals thereafter, determining the torque of that tailboom attachment hardware. This AD was prompted by a review of the tailboom attachment installation, which revealed that the torque value of the bolts specified in the BHTC Model 427 Maintenance Manual and applied during manufacturing was incorrect and exceeded the torque range recommended for the bolts. The actions are intended to prevent an over- torque of the tailboom attachment bolt (bolt), bolt failure, loss of the tailboom, and subsequent loss of control of the helicopter.

This rule establishes, amends, suspends, or revokes Standard Instrument Approach Procedures (SIAPs) and associated Takeoff Minimums and Obstacle Departure Procedures for operations at certain airports. These regulatory actions are needed because of the adoption of new or revised criteria, or because of changes occurring in the National Airspace System, such as the commissioning of new navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed to provide safe and efficient use of the navigable airspace and to promote safe flight operations under instrument flight rules at the affected airports.

We are superseding an existing airworthiness directive (AD) for certain Piper Aircraft, Inc. (type certificate previously held by The New Piper Aircraft Inc.) Models PA-31T and PA-31T1 airplanes. That AD currently requires correcting a model identification error on the aircraft data plate. Since we issued that AD, we have become aware that some owner/operators of the affected airplanes modified the aircraft data plate in error because of confusion in the serial number applicability. Because of the confusion, the manufacturer has issued new service information to clarify affected airplane serial numbers. This new AD requires determining the airplane model based on the serial number and modifying the aircraft data plate to properly identify the airplane model. This new AD also requires doing a detailed search for all applicable airworthiness related documents that apply to any airplane that has an incorrectly marked data plate and take necessary corrective actions based on the search findings. We are issuing this AD to correct the unsafe condition on these products.