Federal Aviation Administration December 9, 2015 – Federal Register Recent Federal Regulation Documents

These special conditions are issued for the Cirrus Aircraft Corporation Model SF50 airplane. This airplane will have a novel or unusual design feature(s) associated with installation of an Auto Throttle System. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

This notice contains a summary of a petition seeking relief from specified requirements of Title 14 of the Code of Federal Regulations. The purpose of this notice is to improve the public's awareness of, and participation in, the FAA's exemption process. Neither publication of this notice nor the inclusion or omission of information in the summary is intended to affect the legal status of the petition or its final disposition.

We propose to adopt a new airworthiness directive (AD) for certain Pratt & Whitney Division (PW) PW4000-94 inch and PW4000-100 inch model turbofan engines. This proposed AD was prompted by a report of a crack find in the high-pressure compressor (HPC) disk. This proposed AD would require performing an ultrasonic inspection (USI) or an eddy current inspection (ECI) of the HPC 10th stage disk. We are proposing this AD to prevent failure of the HPC 10th stage disk, an uncontained disk release, damage to the engine, and damage to the airplane.

We propose to supersede Airworthiness Directive (AD) 96-12-12, which applies to certain Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. AD 96-12-12 currently requires a one-time inspection of the bulkhead assembly at fuselage station (FS) 317.75 for cracks and the installation of one of two reinforcement kits determined by whether cracks were found during the inspection. Since we issued AD 96-12-12, bulkhead cracks were found on airplanes that had complied with AD 96-12-12 and on additional airplanes not affected by AD 96-12-12. This proposed AD would require repetitive inspections of the bulkhead assembly at FS 317.75 for cracks, repair of cracks as necessary, and the installation of a reinforcement modification. We are proposing this AD to correct the unsafe condition on these products.