AD 95-21-08

This amendment adopts a new airworthiness directive (AD), applicable to Boeing Model 757 series airplanes, that requires modification of the engine fuel indication circuits. This amendment is prompted by numerous reports of false indications of engine fuel valve faults, which have led to the flight crew conducting rejected takeoffs (RTO). The actions specified by this AD are intended to reduce such false indications and the flight crew's consequent execution of an RTO at high speed during takeoff roll, which could result in the airplane overrunning the runway, damage to the airplane, and injury to airplane occupants.

Final rule

95-21-08 BOEING: Amendment 39-9394. Docket 94-NM-133-AD. \n\n\tApplicability: Model 757 series airplanes equipped with Pratt & Whitney PW2000 engines, as listed in Boeing Service Bulletin 757-76-0010, dated August 12, 1993; and Model 757 series airplanes equipped with Rolls-Royce RB211-535 engines, as listed in Boeing Service Bulletin 757- 76-0011, dated December 2, 1993; 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 otherwise 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 use the authority provided in paragraph (c) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo reduce false indications of engine fuel valve faults, accomplish the following: \n\n\t(a)\tFor airplanes equipped with Pratt & Whitney PW2000 engines: Within 6 months after the effective date of this AD, modify the engine fuel valve indication circuits in accordance with Boeing Service Bulletin 757-76-0010, dated August 12, 1993. \n\n\t(b)\tFor airplanes equipped with Rolls-Royce RB211-535 engines: Within 18 months after the effective date of this AD, accomplish the modifications specified in paragraphs (b)(1) and (b)(2) of this AD. The modification specified in paragraph (b)(1) must be accomplished either prior to or concurrently with the modification specified in paragraph (b)(2). In any case, both modifications must be completed within 18 months after the effective date of this AD. \n\n\t\t(1)\tModify the engine fuel shutoff valve control in accordance with Boeing Service Bulletin 757-76-0007, Revision 2, dated January 23, 1992. \n\n\tNOTE 2: Modification of the engine fuel shutoff valve control that was accomplished prior to the effective date of this AD in accordance with either Boeing Service Bulletin 757-76-0007 (original issue), dated February 22, 1990, or Revision 1, dated October 31, 1991, is considered acceptable for compliance with paragraph (b)(1) of this AD. \n\n\t\t(2)\tModify the engine fuel valve indication circuits in accordance with Boeing Service Bulletin 757-76-0011, dated December 2, 1993. \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 Manager, 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \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\n\t(e)\tThe modifications shall be done in accordance with Boeing Service Bulletin 757-76- 0010, dated August 12, 1993; Boeing Service Bulletin 757-76-0007, Revision 2, dated January 23, 1992; and Boeing Service Bulletin 757-76-0011, dated December 2, 1993. 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 November 17, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing 757 series airplanes was published in the Federal Register on June 6, 1995 (60 FR 29795). That action proposed to require modifying the engine fuel indication circuits to decrease the number of false fault indications of the engine fuel valve. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\n\tOne commenter supports the proposal. \n\n\tAnother commenter, the airplane manufacturer, suggests that the rule be revised to extend the compliance time for modification of the indication circuits from the proposed 6 months for airplanes equipped with Pratt & Whitney engines and 18 months for airplanes equipped with Rolls Royce engines. The commenter recommends a compliance time of 24 months for all of the affected airplanes. The FAA cannot concur with the commenter's suggestion, since the commenter provided no new data or other information to justify such an extension. The FAA finds that the compliance times, as proposed, are both reasonable and appropriate, in consideration of the fact that: \n\n\t1. the modification requires only 4 work hours to complete; \n\t2. required parts are standard electrical components and an ample number of them are currently available; \n\t3. the compliance time(s) permit the modification to be installed during regularly scheduled maintenance; and \n\t4. airplanes equipped with Rolls Royce engines require the installation of an additional modification (and, therefore, additional time is provided for the completion of that modification). \n\n\tThis commenter also notes that annunciation of the fuel valve position is required on transport category airplanes by section 25.1141(f)(2) of the Federal Aviation Regulations (14 CFR 21.1141(f)(2)),which states: \n\n\t"(f)(2) For power-assisted valves, a means (must be provided) to indicate to the flight crew when the valve -- \n\n\t\t\t(i)\tIs in the fully open or fully closed position, or \n\t\t\t(ii)\tIs moving between the fully open and fully closed position." \n\nThe commenter states that, while the proposed modification is intended to reduce the frequency of spurious annunciations, it is merely a product improvement that simplifies the system; it was designed without full knowledge of the cause of the spurious annunciations, and it is not anticipated to have a significant effect on the rate of rejected takeoffs (RTO) for all reasons. Rather than mandate the installation of this "minor change," whose effect on the rate of RTO's is not predictable, the commenter suggests that the FAA review the reasons for the existence of FAR section 25.1141(f)(2). The commenter contends that such a review is appropriate in light of (1) the existence of FAR section 25.1309(c) ("Equipment, systems,and installation"), which requires, among other things, that warning information be provided to alert the crew to unsafe system operating conditions; (2) the current flight deck "quiet dark cockpit" philosophy; and (3) the design dictation contained in the regulation. The FAA notes this recommendation and may consider it during the current comprehensive review of the FAA's regulation and certification capabilities ("Challenge 2000"). However, regardless of that review, the FAA has determined that the requirements of this AD are warranted to correct the unsafe condition addressed. \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\n\tThere are approximately 272 Model 757 series airplanes equipped with P&W PW2000 engines in the worldwide fleet. The FAA estimates that 219 of these airplanes are currently of U.S. registry and will be affected by this AD. It will take approximately 4 work hours per airplane to accomplish the modification of the engine fuel indication circuits, at an average labor rate of $60 per work hour. The cost of required parts is negligible. Based on these figures, the total cost impact of this AD on U.S. operators of these airplanes is estimated to be $52,560, or $240 per airplane. \n\n\tThere are approximately 302 Model 757 series airplanes equipped with Rolls Royce RB211- 535 engines in the worldwide fleet. The FAA estimates that 119 of these airplanes are currently of U.S. registry and will be affected by this AD. It will take approximately 4 work hours per airplane to accomplish the modification of the engine fuel indication circuits, at an average labor rate of $60 per work hour. The cost of required parts is approximately $194 per airplane. Based on these figures, the total cost impact of this modification on U.S. operators of these airplanes is estimated to be $51,646, or $434 per airplane. \n\n\tAdditionally, for these 119 airplanes equipped with Rolls Royce RB211-535 engines, it will take approximately 28 work hours to accomplish the modification of the engine fuel shutoff valve control, at an average labor rate of $60 per work hour. The cost of required parts is approximately $470 per airplane. Based on these figures, the total cost impact of this modification on U.S. operators of these airplanes is estimated to be $255,850, or $2,150 per airplane. \n\n\tThe total cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \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\tFor the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:\n\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 USC 106(g), 40101, 40113, 44701. § 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: