Daily Rules, Proposed Rules, and Notices of the Federal Government
Contact Pratt Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770; fax (860) 565-4503 for the service information identified in this proposed AD.
We invite you to send any written relevant data, views, or arguments regarding this proposal. Send your
We will post all comments we receive, without change, to
You may examine the docket that contains the proposal, any comments received and any final disposition in person at the DMS Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in
On August 14, 2006, the FAA issued AD 2006-17-08, Amendment 39-14729 (71 FR 49335, August 23, 2006). That AD requires replacing the HPC exit inner and outer brush seal packs with new brush seal packs, or replacing the HPC exit brush seal assembly with a new HPC exit brush seal assembly. That AD was the result of a report of oil leaking into the high pressure turbine (HPT) interstage cavity and igniting, leading to an engine case penetration and engine in-flight shutdown. That condition, if not corrected, could result in uncontained engine failure, damage to the airplane, and injury to passengers.
Since AD 2006-17-08 was issued, an air carrier requested the use of PMA equivalent parts to be included in the AD. We agree. The proposed AD now also applies to engines reassembled with PMA equivalent HPC exit inner and/or outer brush seal packs installed, and allows installation of PMA equivalent HPC exit inner and outer brush seal packs for compliance to the requirements of the AD.
Also since AD 2006-17-08 was issued, we determined that the requirement in paragraph (g) of that AD, of replacing the HPC exit brush seal assembly with a new HPC exit brush seal assembly, is an option for the operators to demonstrate compliance to this proposed AD. Replacing the HPC exit inner and outer brush seal packs instead, is expected to be more economical for operators.
We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. For that reason, we are proposing this AD, which would require replacing the OEM or PMA equivalent HPC exit inner and outer brush seal packs, with OEM or PMA equivalent new brush seal packs. Instructions on replacing these parts can be found in Pratt Whitney Service Bulletin No. PW4G-112-A72-280, Revision 2, or Engine Overhaul Manual.
These actions are interim actions and we may take further rulemaking actions in the future.
We estimate that this proposed AD would affect 76 Pratt Whitney PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 9 work-hours per engine to perform the proposed parts replacement, and that the average labor rate is $80 per work-hour. Required parts would cost about $99,990 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $7,653,950.
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.
We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:
1. Is not a “significant regulatory action” under Executive Order 12866;
2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
3. Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. See the
Air transportation, Aircraft, Aviation safety, Safety.
Under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:
1. The authority citation for part 39 continues to read as follows:
49 U.S.C. 106(g), 40113, 44701.
2. The FAA amends § 39.13 by removing Amendment 39-14729 (71 FR 49335, August 23, 2006) and by adding a new airworthiness directive, Amendment 39-XXXXX, to read as follows:
(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by January 19, 2007.
(b) This AD supersedes AD 2006-17-08, Amendment 39-14729.
(c) This AD applies to Pratt Whitney PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines that were:
(1) Reassembled with a previously used original equipment manufacturer (OEM) or part manufacturer approval (PMA) equivalent high pressure compressor (HPC) exit inner brush seal pack; and
(2) Reassembled with a new or refurbished OEM or PMA equivalent HPC exit diffuser air seal inner land.
(d) These engines are installed on, but not limited to, Boeing 777 airplanes.
(e) This AD results from a request to include PMA equivalent HPC exit inner and outer brush seal packs and to include the engines with PMA equivalent parts already installed, in the AD. We are issuing this AD to prevent uncontained engine failure, damage to the airplane, and injury to passengers.
(f) You are responsible for having the actions required by this AD performed at the following compliance times, unless the actions have already been done.
(g) Replace the HPC exit inner and outer brush seal packs with OEM or FAA-approved PMA equivalent new HPC exit inner and outer brush seal packs as follows:
(1) By 3,000 cycles-in-service (CIS) since a used HPC exit inner brush seal pack and a new or refurbished HPC exit diffuser air seal land were installed in the engine, or by March 31, 2007, whichever occurs later; however
(2) If on March 31, 2007, the used HPC exit inner brush seal pack coupled with a new or refurbished HPC exit diffuser air seal inner land assembly has not accumulated 3,000 CIS, then by 3,000 CIS, or December 31, 2008, whichever occurs first.
(h) Information on replacing HPC exit inner and outer brush seal packs can be found in the Pratt Whitney Alert Service Bulletin No. PW4G-112-A72-280, Revision 2, dated October 2, 2006, and in the engine overhaul manual.
(i) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.
(j) Pratt Whitney Alert Service Bulletin No. PW4G-112-A72-280, Revision 2, dated October 2, 2006, also pertains to the subject of this AD.