Airworthiness Directives; Pratt & Whitney PW4164, PW4168, and PW4168A Series Turbofan Engines

Summary:

The FAA proposes to supersede an existing airworthiness directive (AD) for Pratt Whitney (PW) 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 proposed AD would require the same actions, but at reduced intervals for front pylon mount bolts made from MP159 material. This proposed 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 proposing 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.

Table of Contents

Dates:

We must receive any comments on this proposed AD by February 27, 2006.

Addresses:

Use one of the following addresses to submit comments on this proposed AD:

• By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 97-ANE-44-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

• By fax: (781) 238-7055.

• By e-mail:9-ane-adcomment@faa.gov.

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 proposed AD.

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

For further information contact:

Barbara Caufield, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7146, fax (781) 238-7199.

Supplementary information:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 97-ANE-44-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

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.

Discussion

On December 19, 2002, we issued AD 2000-16-02R1, Amendment 39-12989 (68 FR 28, January 2, 2003). That AD requires initial and repetitive torquechecks for loose or broken front pylon mount bolts made from INCO 718 material and MP159 material. That AD also requires initial and repetitive visual inspections of the primary mount thrust load path. That AD was the result of component testing to assess the low-cycle-fatigue life of the MP159 material bolts and the development of a new design forward engine mount bearing housing. That condition, if not corrected, could result in front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane.

Actions Since AD 2000-16-02R1 Was Issued

Since AD 2000-16-02R1 was issued, the manufacturer performed new fatigue load analysis of the engine mount system, as part of supporting a new 180-minute-flight airplane mission, and supporting updated flight liftoff calculations. The analysis revealed that the MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition.

Relevant Service Information

We have reviewed and approved the technical contents of PW Alert Service Bulletin (ASB) PW4G-100-A71-32, dated April 15, 2005, that describes procedures for performing reduced interval initial and repetitive torque checks of MP159 material front pylon mount bolts.

FAA's Determination and Requirements of the Proposed AD

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. We are proposing this AD, which would require the same torque checks and inspections specified in AD 2000-16-02R1 except for bolts made from MP159 material. This proposed AD would reduce the torque check compliance times for the front pylon mount bolts made from MP159 material to the following:

• For bolts with fewer than 2,200 CSN on the effective date of the proposed AD, initial torque check before accumulating 2,700 CSN, or at the next engine removal for any cause, whichever occurs sooner.

• For bolts with 2,200 CSN or more on the effective date of the proposed AD, initial torque check within the next 500 CIS, or at the next engine removal for any cause, whichever occurs sooner.

• Thereafter, perform torque checks at intervals not to exceed 2,700 CIS since last torque inspection.

The proposed AD would require that you do these actions using the service information described previously and listed in the proposed AD.

Costs of Compliance

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

Special Flight Permits Paragraph Removed

Paragraph (g) of the current AD, AD 2000-16-02R1, contains a paragraph pertaining to special flight permits. Even though this proposed AD 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. 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 § 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 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 have prepared a summary of the costs to comply with this proposal 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, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

§ 39.13

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

Pratt Whitney: Docket No. 97-ANE-44-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by February 27, 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, not to exceed the life limit of 11,000 CSN.

(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, not to exceed the life limit of 11,000 CSN.

(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, not to exceed the front pylon mount bolt P/N 54T670, life limit of 11,000 CSN.

(4) 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.

Issued in Burlington, Massachusetts, on December 22, 2005. Peter A. White,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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