AD 2006-16-05

The FAA is superseding an existing airworthiness directive (AD) for Pratt & Whitney PW4164, PW4168, and PW4168A series turbofan engines. That AD currently requires initial and repetitive torque checks for loose or broken front pylon mount bolts made from INCO 718 material and MP159 material, and initial and repetitive visual inspections of the primary mount thrust load path. This AD requires the same actions, but at reduced intervals for front pylon mount bolts made from MP159 material. This AD results from analysis by the manufacturer that the MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition. We are issuing this AD to prevent front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane.

DATES: This AD becomes effective September 8, 2006. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of September 8, 2006. The Director of the Federal Register previously approved the incorporation by reference of certain publications listed in the regulations as of February 6, 2003 (68 FR 28, January 2, 2003).

Final rule.

2006-16-05 Pratt & Whitney: Amendment 39-14705. Docket No. 97-ANE- 44-AD.

Effective Date

(a) This AD becomes effective September 8, 2006.

Affected ADs

(b) This AD supersedes AD 2000-16-02R1.

Applicability

(c) This AD applies to Pratt & Whitney (PW) PW4164, PW4168, and PW4168A series turbofan engines, with front pylon mount bolts, part number (P/N) 54T670 or 51U615, installed. These engines are installed on, but not limited to, Airbus A330 series airplanes.

Unsafe Condition

(d) This AD results from analysis by the manufacturer that MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition. We are issuing this AD to prevent front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

INCO 718 Material Bolts Torque Checks

(f) Perform initial and repetitive torque checks of INCO 718 material front pylon mount bolts, P/N 54T670, and replace, if necessary, with new bolts, using the Accomplishment Instructions of PW Alert Service Bulletin (ASB) PW4G-100-A71-9, Revision 1, dated November 24, 1997, as follows:

(1) For front pylon mount bolts, P/N 54T670, with fewer than 1,000 cycles-since-new (CSN) on the effective date of this AD, do the following using Part (A) of the Accomplishment Instructions of the ASB:

(i) Perform an initial torque check before accumulating 1,250 CSN or at the next engine removal for cause, whichever occurs sooner.

(ii) Thereafter, perform torque checks at intervals of no fewer than 750 or no more than 1,250 cycles-in-service (CIS) since last torque check.

(2) For front pylon mount bolts, P/N 54T670, with 1,000 CSN or more but fewer than 5,750 CSN on the effective date of this AD, do the following using Part (A) of the Accomplishment Instructions of the ASB:

(i) Perform an initial torque check within 250 CIS after the effective date of this AD, or at the next engine removal for any cause, whichever occurs sooner.

(ii) Thereafter, perform torque checks at intervals of no fewer than 750 or no more than 1,250 CIS since last torque check.

(3) For front pylon mount bolts, P/N 54T670, with 5,750 CSN or more on the effective date of this AD, do the following using Part (B) of the Accomplishment Instructions of the ASB:

(i) Perform an initial torque check within 250 CIS after the effective date of this AD, or before the next engine removal for any cause, whichever occurs sooner.

(ii) Thereafter, perform torque checks at intervals of no fewer than 750 or no more than 1,250 CIS since last torque check.

(4) Remove from service front pylon mount bolts P/N 54T670, at or before reaching the life limit of 11,000 CSN.
(5) Before further flight, replace all four bolts using Part (A), Paragraph 1(D) of the Accomplishment Instructions of the ASB, if any of the bolts are loose or broken.

MP159 Material Bolts Inspections

(g) Perform initial and repetitive torque checks of front pylon mount bolts, P/N 51U615, using the Accomplishment Instructions of PW ASB PW4G-100-A71-32, dated April 15, 2005, as follows:

(1) For front pylon mount bolts with fewer than 2,200 CSN on the effective date of this AD, perform the initial torque inspection before accumulating 2,700 CSN, or at the next engine removal for any cause, whichever occurs sooner.

(2) For front pylon mount bolts with 2,200 CSN or more on the effective date of this AD, perform the initial torque check within the next 500 CIS, or at the next engine removal for any cause, whichever occurs sooner.

(3) Thereafter, perform torque inspections at intervals not to exceed 2,700 CIS since last torque inspection.

(4) Before further flight, replace all four bolts using Paragraph 1.E. of the Accomplishment Instructions of the ASB, if any are loose or broken.

Primary Mount Thrust Load Path Inspections

(h) Perform initial and repetitive visual inspections of the primary mount thrust load path using the Accomplishment Instructions of PW ASB PW4G-100-A71-18, Revision 2, dated January 15, 2002, as follows:

(1) For forward engine mount assemblies with fewer than 1,000 CSN on the effective date of this AD, perform the initial visual inspection at the earlier of the following:

(i) Before accumulating 1,250 CSN; or

(ii) The next engine removal for any cause.

(2) For forward engine mount assemblies with 1,000 CSN or more on the effective date of this AD, perform the initial visual inspection within 250 CIS after the effective date of this AD, or the next engine removal for any cause, whichever occurs sooner.

(3) Thereafter, perform visual inspections at intervals of no fewer than 750 or no more than 1,250 CIS since-last-visual- inspection.

(4) Before further flight, replace all cracked parts with serviceable parts and inspect the primary thrust load path components using Paragraph 4 of the Accomplishment Instructions of the ASB.

Terminating Action

(i) Replacement of the forward engine mount bearing housing, P/N 59T794 or P/N 54T659 with P/N 52U420, using SB PW4G-100-71-22, dated January 15, 2002, constitutes terminating action to the inspection requirements of paragraph (h) of this AD.

Alternative Methods of Compliance

(j) 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.

Related Information

(k) None.

Material Incorporated by Reference

(l) You must use the Pratt & Whitney service information specified in Table 1 of this AD to perform the actions required by this AD. The Director of the Federal Register approved the incorporation by reference ofPratt & Whitney Alert Service Bulletin (ASB) PW4G-100-A71-32, dated April 15, 2005, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. The Director of the Federal Register previously approved the incorporation by reference of Pratt & Whitney ASB PW4G-100-A71-9, Revision 1, dated November 24, 1997, as of October 16, 2000, and, ASB PW4G-100-A71-18, Revision 2, dated January 15, 2002, and ASB PW4G-100-71-22, dated January 15, 2002, as of February 6, 2003. Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700, fax (860) 565-1605 for the service information identified in this AD. You may review copies at the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL- 401, Washington, DC 20590-0001, on the Internet at http://dms.dot.gov , or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html .

Table 1 Incorporation by Reference

Alert Service Bulletin (ASB) or Service Bulletin (SB) No.
Page
Revision
Date

1
1
November 24, 1997

2
Original
July 31, 1997

3
1
November 24, 1997

4-7
Original
July 31, 1997

8-9
1
November 24, 1997
ASB PW4G-100-A71-9

Total Pages: 11
10-11
Original
July 31, 1997

1-2
2
January 15, 2002

3
1
December 9, 1999

4
2
January 15, 2002

5-6
Original
September 15, 1999

7
2
January 15, 2002
ASB PW4G-100-A71-18

Total Pages: 12
8-12
Original
September 15, 1999
SB PW4G-100-71-22 Total Pages: 8
ALL
Original
January 15, 2002
ASB PW4G-100-A71-32 Total Pages: 9
ALL
Original
April 15, 2005

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to Pratt & Whitney PW4164, PW4168, and PW4168A series turbofan engines. We published the proposed AD in the Federal Register on December 29, 2005 (70 FR 77075). That action proposed to require initial and repetitive torque checks for loose or broken front pylon mount bolts made from INCO 718 material and MP159 material. That action also proposed to require initial and repetitive visual inspections of the primary mount thrust load path, but at reduced intervals from AD 2000-16-02R1 for front pylon mount bolts made from MP159 material.

Examining the AD Docket

You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.

Comments

We provided the public the opportunity to participate in the development of this AD. We received no comments on the proposal or on the determination of the cost to the public.

Bolt Life Limit Clarification

For clarification, we removed three bolt life limit references from paragraphs (f)(1), (f)(2), and (f)(3) and added paragraph (f)(4). The added paragraph states to remove from service front pylon mount bolts P/N 54T670, at or before reaching the life limit of 11,000 CSN.

Conclusion

We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD with the changes described previously.

Costs of Compliance

About 60 engines installed on airplanes of U.S. registry are affected by this AD. We estimate that it will take about four work- hours per engine to perform the actions, and that the average labor rate is $65 per work-hour. Required parts will cost about $26,500 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $1,605,600.

Special FlightPermits Paragraph Removed

Paragraph (g) of the AD we are superseding, AD 2000-16-02R1, contains a paragraph pertaining to special flight permits. Even though this final rule does not contain a similar paragraph, we have made no changes with regard to the use of special flight permits to operate the airplane to a repair facility to do the work required by this AD. In July 2002, we published a new Part 39 that contains a general authority regarding special flight permits and airworthiness directives. See Docket No. FAA-2004-8460, Amendment 39-9474 (69 FR 47998, July 22, 2002). Thus, when we now supersede ADs we will not include a specific paragraph on special flight permits unless we want to limit the use of that general authority granted in section 39.23.

Authority for This Rulemaking

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.

Regulatory Findings

We have determined that 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); and

(3) 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.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "AD Docket No. 97-ANE-44-AD" in your request.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

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

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing Amendment 39-12989 (68 FR 28, January 2, 2003) and by adding a new airworthiness directive, Amendment 39-14705, to read as follows: