Federal Aviation Administration November 23, 2011 – Federal Register Recent Federal Regulation Documents

This notice contains a summary of a petition seeking relief from specified requirements of 14 CFR. The purpose of this notice is to improve the public's awareness of, and participation in, this aspect of FAA's regulatory activities. 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 Airbus Model A319, A320, and A321 airplanes that would supersede an existing AD. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Several cases of corrosion of the Main Landing Gear (MLG) support Rib 5 fitting lug bores have been reported on A320 family aeroplanes. * * * If not detected, the cracking may lead to the complete failure of the fitting and thus could affect the structural integrity of the MLG installation. EASA AD 2007-0213 was issued to address this condition * * *. After that AD was issued, a case of Rib 5, ruptured at the 4 o'clock position, was discovered on an aeroplane on which the terminating action of EASA AD 2007-0213 had already been embodied * * *. Investigation of that case revealed that corrosion damage and cracking that should have been removed by repair machining was below the level of detectability of the Non Destructive Test (NDT) technique that cleared the surfaces prior to bush installation. * * * * * The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

We propose to adopt a new airworthiness directive (AD) for Pratt & Whitney JT9D-7R4D, -7R4D1, -7R4E, -7R4E1, -7R4G2, -7R4H1, and - 7R4E4 turbofan engines. This proposed AD would establish a new lower life limit for high-pressure turbine (HPT) 1st stage air seals, part number (P/N) 735907, and would require removing them from service using a drawdown schedule. This proposed AD was prompted by the determination that a new lower life limit for the HPT 1st stage air seals, P/N 735907, is necessary. We are proposing this AD to prevent critical life-limited rotating engine part failure and damage to the airplane.