Federal Aviation Administration November 19, 2013 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for all DORNIER LUFTFAHRT GmbH Model 228-212 airplanes. 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 main landing gear axle failure caused by initial fatigue cracking and small pre-damage by corrosion. We are issuing this proposed AD to require actions to address the unsafe condition on these products.

We propose to supersede existing airworthiness directive (AD) 2012-26-14 that applies to all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-715A1-30, BR700-715B1-30, and BR700-715C1-30 turbofan engines. AD 2012-26-14 currently requires removal from service of the high-pressure (HP) compressor stages 1 to 6 rotor disc assembly before exceeding certain thresholds. Since we issued AD 2012-26-14, RRD developed a new silver-free nut that, if installed with a new HP compressor stages 1 to 6 disc assembly, would correct the unsafe condition identified in AD 2012-26-14. Therefore, we propose to supersede AD 2012-26-14 to restrict the applicability to engines exposed to silver plated nuts. Additionally, we are removing the terminating action statement from AD 2012-26-14 based on a comment received. This proposed AD would require removal from service of certain HP compressor stages 1 to 6 rotor disc assemblies before exceeding certain thresholds. We are proposing this AD to prevent failure of the HP compressor stages 1 to 6 rotor disc assembly, which could lead to an uncontained engine failure and damage to the airplane.