AD 2006-09-02 ACTIVE

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 757-200 and -200PF series airplanes equipped with Pratt & Whitney engines. This AD requires repetitive detailed inspections to detect and correct any gap between the strut fitting and the forward engine mount assembly and applicable related investigative actions, corrective actions, and other specified actions. This AD results from a report indicating that gaps had been found between the strut fitting and the forward engine mount assembly. We are issuing this AD to detect and correct any gaps between the strut fitting and the forward engine mount assembly of both engines, which could result in separation of the engine from the wing and subsequent loss of control of the airplane.

Final rule; request for comments.

2006-09-02 Boeing: Amendment 39-14572. Docket No. FAA-2006-24557; Directorate Identifier 2006-NM-082-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective May 11, 2006. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 757-200 and -200PF series airplanes, certificated in any category, equipped with Pratt & Whitney engines, as identified in Boeing Alert Service Bulletin (ASB) 757-71A0085, dated March 2, 2006. \n\nUnsafe Condition \n\n\t(d) This AD results from a report indicating that gaps had been found between the strut fitting and the forward engine mount assembly. We are issuing this AD to detect and correct any gaps found between the strut fitting and the forward engine mount assembly of both engines, which could result in separation of the engine from the wing and subsequent loss of control of the airplane. \n\nCompliance \n\n\t(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. \n\nInitial Inspection \n\n\t(f) Within 90 days after the effective date of this AD or within 3,000 flight cycles since the most recent installation of each engine, whichever occurs later: For each engine, perform a detailed inspection to detect any gap between the strut fitting and the forward engine mount assembly of the engine, and before further flight, do all applicable related investigative actions, corrective actions, and other specified actions; in accordance with Part 1 of the Accomplishment Instructions of Boeing ASB 757-71A0085, dated March 2, 2006. \n\n\tNote 1: In the Accomplishment Instructions of the ASB, the manufacturer provides instructions to repair or replace parts before "subsequent" flight if damage is found on parts. However, the manufacturer also specifies to write to the manufacturer if necessary for repair information. This AD requires that any deviation from the instructions provided in the ASB must be approvedas an alternative method of compliance under paragraph (h) of this AD. \n\nRepetitive Inspections \n\n\t(g) Within 3,000 flight cycles after accomplishing the requirements of paragraph (f) of this AD: Perform a detailed inspection to detect any gap between the strut fitting and the forward mount assembly of both engines, and before further flight, do all applicable related investigative actions, corrective actions, and other specified actions; in accordance with Part 2 of the Accomplishment Instructions of Boeing ASB 757-71A0085, dated March 2, 2006. Thereafter, repeat the actions specified in Part 2 of the Accomplishment Instructions of the ASB at intervals not to exceed 3,000 flight cycles. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \n\n\t(2) Before using any AMOC approved in accordance with Sec. 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office. \n\n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(i) You must use Boeing Alert Service Bulletin 757-71A0085, dated March 2, 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif Building, Washington, DC; 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 the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .

Discussion \n\n\tWe have received a report indicating that gaps have been found between the strut fitting and the forward engine mount assembly above the Number 1 engine on Boeing Model 757-200 and -200PF series airplanes. The gap was caused by the loosening of vertical tension bolts that were installed on the forward engine mount installation. The gap at the two forward engine mount bolts was \3/16\ of an inch and the gap at the aft two engine mount bolts was \1/8\ of an inch. In addition, wear damage was also found on the surfaces of the forward engine mount assembly and the strut fitting. This condition, if not corrected, could result in separation of the engine from the wing and subsequent loss of control of the airplane. \n\nRelevant Service Information \n\n\tWe have reviewed Boeing Alert Service Bulletin (ASB) 757-71A0085, dated March 2, 2006. \n\n\tPart 1 of the Accomplishment Instructions of the ASB describes procedures for an initial detailed inspection to detect gaps between the strut fitting and the forward engine mount assembly of both engines. Part 1 also describes the following related investigative actions, corrective actions, and other specified actions. If there is no gap found, Part 1 specifies applying inspection torque to each engine mount bolt and applying torque stripe between each bolt and forward engine mount surface. Part 1 also specifies, for certain limits, applying installation torque to all the bolts. If there is a gap between the strut fitting and forward engine mount assembly at a bolt location, Part 1 specifies a detailed inspection to detect damage of the parts and repairing or replacing parts. In addition, Part 1 advises operators to write to Boeing if necessary for repair information. \n\n\tPart 2 of the Accomplishment Instructions of the ASB describes similar procedures for repetitive detailed inspections to detect gaps between the strut fitting and the forward engine mount assembly of both engines. Part2 also describes the following related investigative actions, corrective actions, and other special actions. If there is no gap found but the torque stripe on one or more bolts is cracked, broken or missing, Part 2 specifies applying an inspection torque to each forward engine mount bolt and applying a new torque stripe between each bolt and forward engine mount surface. Part 2 also specifies, if there is a gap found between the strut fitting and forward engine mount assembly at a bolt location, performing a detailed inspection for damage of the forward engine mount and strut fitting and repairing or replacing any damaged parts. In addition, Part 2 advises operators to write to Boeing if necessary for repair information. \n\nFAA's Determination and Requirements of This AD \n\n\tThe unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to detect and correct any gaps between the strut fitting and the forward engine mount assembly. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and the ASB." \n\nDifferences Between the AD and the ASB \n\n\tAlthough the ASB specifies repairing or replacing, if damage is found on parts before subsequent flights, it also advises operators to write to the manufacturer if necessary for repair information. We have clarified in Note 1 of this AD that any deviation from the Accomplishment Instructions provided in the ASB must be approved as an alternative method of compliance under paragraph (h) of this AD. \n\nInterim Action \n\n\tThis is considered to be interim action. The manufacturer has advised that it currently is developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking. \n\nFAA's Determination of theEffective Date \n\n\tSince an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days. \n\nComments Invited \n\n\tThis AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2006- 24557; Directorate Identifier 2006-NM-082-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it. \n\n\tWe will post all comments we receive, without change, to http://dms.dot.gov , including any personal informationyou provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov. \n\nExamining the Docket \n\n\tYou may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647- 5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after theDocket Management System receives them. \n\nAuthority for This Rulemaking \n\n\tTitle 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. \n\n\tWe 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. \n\nRegulatory Findings \n\n\tWe 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. \n\n\tFor the reasons discussed above, I certify that the regulation: \n\n\t1. Is not a "significant regulatory action" under Executive Order 12866; \n\n\t2. Is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\n\t3. 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. \n\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):

Use one of the following addresses to submit comments on this AD. \n\n\tDOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically. \n\n\tGovernment-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically. \n\n\tMail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590. \n\n\tFax: (202) 493-2251. \n\n\tHand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. \n\n\tContact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this AD.

Dennis Stremick, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6450; fax (425) 917-6590.