AD 98-04-14

This amendment adopts a new airworthiness directive (AD) that is applicable to Pratt & Whitney PW4164 and PW4168 series turbofan engines. This action requires initial and repetitive inspections for loose or broken front pylon mount bolts, replacement, if necessary, with new bolts, and establishment of a new cyclic life limit. This amendment is prompted by new flight test data that indicate higher than predicted loads. The actions specified in this AD are intended to prevent front pylon mount bolt failure, which could result in engine separation from the aircraft.

Final rule; request for comments.

98-04-14 Pratt & Whitney: Amendment 39-10326. Docket 97-ANE-44-AD.
Applicability: Pratt & Whitney PW4164 and PW4168 series turbofan engines, with front pylon mount bolts, Part Number (P/N) 54T670, installed. These engines are installed on but not limited to Airbus Industrie A330 series aircraft.
Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, therequest should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent front pylon mount bolt failure, which could result in engine separation from the aircraft, accomplish the following:
(a) Perform initial and repetitive torque checks of front pylon mount bolts, and replace, if necessary, with new bolts, in accordance with the Accomplishment Instructions of Pratt & Whitney Service Bulletin (SB) No. PW4G-100-A71-9, Revision 1, dated November 24, 1997, as follows:
(1) For front pylon mount bolts with more than 1,000 cycles since new (CSN) but less than 5,750 CSN on the effective date of this AD, accomplish the following in accordance with Part (A) of the Accomplishment Instructions of the SB:
(i) Perform an initial torque check within 250 cycles in service (CIS) after the effective date of this AD, or prior to the next engine removal for any cause, whichever occurs first.
(ii) Thereafter, perform torque checks at intervals not less than 750 or greater than 1,250 CIS since last torque check, not to exceed 11,000 CSN.
(2) For front pylon mount bolts with 5,750 or more CSN but less than 8,000 CSN on the effective date of this AD, accomplish the following in accordance with Part (B) of the Accomplishment Instructions of the SB:
(i) Perform an initial torque check within 250 CIS after the effective date of this AD, or prior to the next engine removal for any cause, whichever occurs first.
(ii) Thereafter, perform torque checks at intervals not less than 750 or greater than 1,250 CIS since last torque check, not to exceed 11,000 CSN.
(3) For front pylon mount bolts with 8,000 or more CSN but less than 11,000 CSN on the effective date of this AD, perform an inspection in accordance with the schedule and procedures of the Appendix to the SB.
(4) Prior to further flight, replace all four bolts in accordance with Part (A), Paragraph 1(D) of the Accomplishment Instructions of the SB, if any are found loose or broken.
(b) This AD establishes a new life limit of 11,000 CSN for front pylon mount bolts, P/N 54T670. Except as provided in paragraph (c) of this AD, no front pylon mount bolts may exceed this new life limit after the effective date of this AD.
(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the inspection requirements of this AD can be accomplished.
(e) The actions required by this AD shall be done in accordance with the following PW SB:

Document No.
Revision
Pages
Date
PW4G-100-A71-9
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

10,11
Original
July 31, 1997
Total pages: 11.

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-4503. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment becomes effective on March 13, 1998.

The Federal Aviation Administration (FAA) has received data from flight testing of Pratt & Whitney PW4164 and PW4168 series turbofan engines installed on Airbus Industrie A330 series aircraft. The flight testing revealed higher than predicted loads for front pylon mount bolts, resulting in decreased service life. At this time, there are no U.S. operators of this aircraft/engine combination. This condition, if not corrected, could result in front pylon mount bolt failure, which could result in engine separation from the aircraft.
The FAA has reviewed and approved the technical contents of Pratt & Whitney Service Bulletin (SB) No. PW4G-100-A71-9, Revision 1, dated November 24, 1997, that describes procedures for initial and repetitive inspections for loose or broken front pylon mount bolts, replacement, if necessary, with new bolts, and removal of bolts from service upon reaching a prescribed service life limit.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to prevent front pylon mount bolt failure. This AD requires initial and repetitive inspections for loose or broken front pylon mount bolts, replacement, if necessary, with new bolts, and establishment of a new cyclic life limit of 11,000 cycles in service (CIS). When parts accumulate 6,000 and 8,000 cycles since new (CSN), this AD requires different inspection procedures to be followed, but the manufacturer has informed the FAA that they are developing new material front pylon mount bolts that may be ready and certified for installation prior to any parts currently in service accumulating 6,000 CSN. When the new material parts are available, future rulemaking may be forthcoming that may constitute terminating action to the repetitive inspections required by this AD. The actions would be required to be accomplished in accordance with the SB described previously.
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 97-ANE-44-AD." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: