AD 2010-24-09

This AD is effective December 28, 2010.

James Gray, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7742; fax (781) 238-7199; e-mail: james.e.gray@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to the specified products. That NPRM published in the Federal Register on June 3, 2010 (75 FR 31330). That NPRM proposed to require:

• A one-time visual inspection of the No. 3 bearing oil pressure tube, P/N 51J041-01, P/N 50J604-01, or P/N 50J924-01; and

• Removal from service if found cracked or repaired, or if suspected that the tube was repaired; and

• A prohibition on installing repaired tubes.

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA's response to each comment.

United Airlines asked us to revise paragraph (e) of the proposed AD to inspect the tube when the tube is in the piece-part condition. United Airlines felt that changing paragraph (e) of the proposed AD will make our intent clear.

We agree. We revised paragraph (e) of the proposed AD to say “You are responsible for having the actions required by this AD performed the next time the No. 3 bearing oil pressure tube is in the piece-part condition after the effective date of this AD, unless the actions have already been done.” We also added a new heading “Definitions” and new paragraph (i) that defines piece-part condition for the oil pressure tube.

Delta Airlines, Inc. and United Airlines asked us to clarify the types of repaired tubes that must be removed. Delta Airlines Inc. and United Airlines said the body of the NPRM states that weld repairs were the source of the failures.

We don't agree. All repairs are unacceptable, not just weld repairs. Further, the original equipment manufacturer also revised their applicable repair manual(s) to remove all repairs to these tubes.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

We estimate that this AD would affect 973 PW4000 series turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 10 minutes per engine to perform the one-time visual inspection when the tube has been removed, and that the average labor rate is $85 per work-hour. Required parts would cost about $9,154 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $8,923,383.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):