AD 99-15-10

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 777 series airplanes. This action requires replacement of a certain engine-driven pump (EDP) supply shutoff valve, which is located in the aft strut fairing, with a new shutoff valve. This amendment is prompted by reports of failure of the shutoff valve due to corrosion in the direct current motor in the shutoff valve. The actions specified in this AD are intended to prevent failure of an EDP supply shutoff valve. Such failure, in the event of an engine fire, could result in an uncontrolled fire in the engine compartment.

Final rule; request for comments

99-15-10 BOEING: Amendment 39-11230. Docket 99-NM-113-AD. \n\n\tApplicability: Model 777 series airplanes, equipped with an engine-driven pump supply shutoff valve having Boeing part number S271W741-21; certificated in any category. \n\n\tNOTE 1: This AD applies to each airplane 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 airplanes 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, the request should include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent failure of an engine-driven pump (EDP) supply shutoff valve, which, in the event of an engine fire, could result in an uncontrolled fire in the engine compartment, accomplish the following:\n\n Replacement \n\n\t(a)\tExcept as provided by paragraph (b) of this AD, within 90 days after the effective date of this AD, replace any EDP supply shutoff valve, Boeing part number (P/N) S271W741-21, that is located in each aft strut fairing, with a new EDP supply shutoff valve, Boeing P/N S271W741-22, in accordance with Boeing Alert Service Bulletin 777-29A0022, Revision 1, dated May 21, 1999. \n\n\t(b)\tWhere Boeing Alert Service Bulletin 777-29A0022, Revision 1, dated May 21, 1999, specifies that replacements may be accomplished in accordance with an operator's "equivalent procedure," those actions must be accomplished in accordance with the applicable chapter of the Boeing 777 Airplane Maintenance Manual (AMM) specified in the alert service bulletin. \n\nAlternative Methods of Compliance \n\n\t(c)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\tNOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(d)\tSpecial 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 airplane to a location where the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(e)\tThe replacement shall be done in accordance with Boeing Alert Service Bulletin 777-29A0022, Revision 1, dated May 21, 1999. 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(f)\tThis amendment becomes effective on August 5, 1999.

The FAA has received reports of failures of the engine-driven pump (EDP) supply shutoff valves located in the aft strut fairings. Subsequently, the airplane manufacturer investigated this failure mode and reported to the FAA that failure of the supply shutoff valves was caused by corrosion in the direct current (DC) motors in the valves. Such corrosion forms between the stator and rotor in the DC motor in the supply shutoff valve assembly. Since the DC motor drives the actuator in the motor-operated supply shutoff valve to the commanded position, corrosion in the motor prevents the motor and the actuator from operating. In the event of an engine fire, failure of an EDP supply shutoff valve, if not corrected, could result in an uncontrolled fire in the engine compartment. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 777-29A0022, Revision 1, dated May 21, 1999, which describes procedures for replacement of a certain EDP supply shutoff valve with a new EDP supply shutoff valve. The Boeing alert service bulletin references Parker-Hannifin Service Bulletin 2910044-29-48, "Introduction of Motor Operated Shutoff Valve, Part Number (P/N) 2960034-101," as an additional source of service information to accomplish the replacement. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other Boeing Model 777 series airplanes of the same type design, this AD is being issued to prevent failure of an EDP supply shutoff valve due to corrosion in the DC motor in the shutoff valve. In the event of an engine fire, failure of an EDP supply shutoff valve could result in an uncontrolled fire in the engine compartment. This AD requires replacement of a certain EDP supply shutoff valve, which is located in the aft strut fairing, with a new shutoff valve. \n\nDifferences Between the AD and the Alert Service Bulletin \n\n\tBoeing Alert Service Bulletin 777-29A0022, Revision 1, specifies that the replacement actions required by this AD may be accomplished in accordance with the procedures specified in the alert service bulletin, or in accordance with an "operator's equivalent procedure." However, this AD requires that the actions be accomplished in accordance with the procedures specified in the Boeing alert service bulletin. An "operator's equivalent procedure" may be used only if approved as an alternative method of compliance in accordance with paragraph (c) of this AD. \n\nDetermination of Rule's Effective Date \n\n\tSince 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. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affectingflight 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 shall 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. \n\n\tComments 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. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 99-NM-113-AD." The postcard will be date stamped and returned to the commenter. \n\nRegulatory Impact \n\n\tThe 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. \n\n\tTheFAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it 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." \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\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: