The FAA is superseding an existing airworthiness directive (AD) 2012-04-13 for all RR model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of the AD. That AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This continues to require those repetitive inspections and follow-on corrective actions. This new AD changes the definition of a shop visit to be less restrictive. This AD was prompted by our determination that the definition of ”shop visit” in the existing AD is too restrictive, in that it would require operators to inspect more often than required to ensure safety. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

DATES: This AD is effective April 11, 2012. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of April 11, 2012.

Based on the service information, the FAA estimates that this AD will affect about 371 products of U.S. registry. We also estimate that it will take about 20 work-hours per product to comply with this AD. The average labor rate is $85 per work-hour. No parts will be required per product. Based on these figures, the FAA estimates the cost of the AD on U.S. operators to be $630,700.

2012-04-13.pdf

The FAA is revising an existing airworthiness directive (AD) 2010-11-09 for TAE models TAE 125-01 and TAE 125-02-99 reciprocating engines installed on, but not limited to, Diamond Aircraft Industries Model DA 42 airplanes. That AD currently requires initial and repetitive replacements of proportional pressure reducing valves (PPRVs) (also known as propeller control valves). This new AD relaxes the repetitive replacement interval from a 300-hour interval to a 600-hour interval for PPRVs, P/N 05-7212-E002801, on TAE 125-02-99 engine. This AD was prompted by TAE increasing the life of the PPRV, part number (P/N) 05-7212-E002801, on TAE 125-02-99 engines from 300 to 600 hours. We are issuing this AD to prevent engine in-flight shutdown, possibly resulting in reduced control of the aircraft.

DATES: This AD is effective April 11, 2012. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of April 11, 2012. The Director of the Federal Register approved the incorporation by reference of certain other publications listed in this AD as of July 13, 2010 (75 FR 32253, June 8, 2010).

2010-11-09r1.pdf

The FAA is adopting a new airworthiness directive (AD) 2012-04-14 for RB211-Trent 800 series turbofan engines. This AD requires inspecting the front combustion liner head section for cracking, and if found cracked, removing the front combustion liner head section from service at the next shop visit. This AD was prompted by mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. Specifically, routine inspections revealed cracking on the head sections of two RB211-Trent 800 front combustion liners. We are issuing this AD to prevent uncontained engine failure and damage to the airplane.

DATES: This AD becomes effective April 11, 2012. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of April 11, 2012.

Estimate is that this AD will affect about 125 products of U.S. registry. The FAA also estimates that it will take about 10 work-hours per engine to inspect and 10 additional work-hours for those combustion liners that require replacement. The average labor rate is $85 per work-hour. Required parts will cost about $525,000 per engine. The FAA expects that four front combustion liners will require replacement. Based on these figures, we estimate the cost of the AD on U.S. operators to be $2,209,650.

2012-04-14.pdf

The FAA is correcting an airworthiness directive (AD) 2011-12-10 that was published in the Federal Register. That AD applies to Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, R22 Mariner, R44, and R44 II helicopters. The paragraph reference in paragraph (b) of the Compliance section is incorrect. Paragraph (b) references paragraph (d), when it should reference paragraph (c). This document corrects that error. Additionally, the word ”inspection” has been added in paragraph (b) for clarification. In all other respects, the original document remains the same.

DATES: The effective date of this final rule is March 5, 2012. The effective date for AD 2011-12-10 remains July 5, 2011.

See link for original AD and correction issued by the FAA

2011-12-10_correction.pdf