AD 99-27-06 SUPERSEDED

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757-200, -200PF, and -200CB series airplanes, that requires repetitive inspections of the engine thrust control cable system to detect discrepancies of the wire rope, fittings, and pulleys; and replacement, if necessary. This amendment also requires a one-time inspection to determine the part number of certain pulleys and replacement of existing pulleys with new pulleys, if necessary; and modification of the engine thrust control cable installation. This amendment is prompted by reports of failure of certain engine thrust control cables. The actions specified by this AD are intended to prevent failure of certain engine thrust control cables, which could result in a severe asymmetric thrust condition during landing, and consequent reduced controllability of the airplane.

Final rule.

99-27-06 BOEING: Amendment 39-11487. Docket 98-NM-323-AD. Issued December 22, 1999.\n\tApplicability: Model 757-200, -200PF, and -200CB series airplanes powered by Rolls-Royce RB211-535C/E4/E4B turbofan engines, 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 (f) 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\tTo prevent engine thrust control cable failure, which could result in a severe asymmetric thrust condition during landing, and consequent reduced controllability of the airplane, accomplish the following:\n\nInspections and Corrective Actions \n\t(a)\tWithin 24 months or 6,000 flight hours after the effective date of this AD, whichever occurs first: Accomplish the "Thrust Control Cable Inspection Procedure" specified in Appendix 1. (including Figure 1) of this AD to verify the integrity of the thrust control cables. Prior to further flight, repair any discrepancy found in accordance with the procedures described in the Boeing 757 Maintenance Manual. Repeat the inspection thereafter at intervals not to exceed 24 months or 6,000 flight hours, whichever occurs first.\n\t(b)\tFor airplanes having line numbers 1 through 636 inclusive: Within 24 months or 6,000 flight hours after the effective date of this AD, whichever occurs first, perform a one-time inspection of the 8 engine thrust control cable pulleys in the struts (4 in each strut) to determine the part number (P/N) of each pulley. If any pulley having P/N 65B80977-1 or BAC30M4 is installed, prior to further flight, replace it with a pulley having P/N 255T1232-7, in accordance with the procedures described in the Boeing 757 Airplane Maintenance Manual.\n\tNOTE 2: The location of the pulleys to be inspected in accordance with paragraph (b) of this AD is specified in Chapters 53-11-53-04, 76-11-52-01, and 76-11-52-02 of the Boeing 757 Illustrated Parts Catalog.\n\nModifications\n\t(c)\tFor airplanes identified in Boeing Service Bulletin 757-76-1, dated May 18, 1984: Within 24 months or 6,000 flight hours after the effective date of this AD, whichever occurs first, remove the guide bracket of the engine thrust control cable located on the front spar of the right wing in accordance with the service bulletin.\n\t(d)\tFor airplanes identified in Boeing ServiceBulletin 757-76-0005, dated May 5, 1988: Within 24 months or 6,000 flight hours after the effective date of this AD, whichever occurs first, remove the engine thrust control cable breakaway stop assemblies, and replace sections of the engine thrust control cables with smaller diameter cables in accordance with the service bulletin.\n\t(e)\tFor airplanes identified in Boeing Service Bulletin 757-30A0018, Revision 2, dated September 9, 1999: Within 60 days after the effective date of this AD, install a support bracket assembly between the window heat wire bundle and the engine thrust control cable; and adjust the wire bundle clearance, as necessary, to parallel the minimum clearance specified in Boeing Alert Service Bulletin 757-30A0018, Revision 1, dated September 17, 1998; or Boeing Service Bulletin 757-30A0018, Revision 2, dated September 9, 1999.\n\nAlternative Method of Compliance\n\t(f)\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\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 Special Flight Permits\n\t(g)\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\t(h)\tExcept as provided by paragraphs (a) and (b) of this AD, the modifications shall be done in accordance with Boeing Service Bulletin 757-76-1, dated May 18, 1984; Boeing Service Bulletin 757-76-0005, dated May 5, 1988; Boeing Alert Service Bulletin 757-30A0018, Revision 1, dated September 17, 1998; and Boeing Service Bulletin 757-30A0018, Revision 2, dated September 9, 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\t(i)\tThis amendment becomes effective on February 7, 2000.\n\n\nAPPENDIX 1.\n\nTHRUST CONTROL CABLE INSPECTION PROCEDURE\n\n\n1. General\n\tA. Clean the cables, if necessary, for the inspection, in accordance with Boeing 757 Maintenance Manual 12-21-31.\n\tB. Use these procedures to verify the integrity of the thrust control cable system. The procedures must be performed along the entire cable run for each engine. To ensure verification of the portions of the cables which are in contact with pulleys and quadrants, the thrust control must be moved by operation of the thrust and/or the reverse thrust levers to expose those portions of the cables.\n\tC. The first task is an inspection of the control cable wire rope. The second task is an inspection of the control cable fittings. The third task is an inspection of the pulleys.\n\tNOTE: These three tasks may be performed concurrently at one location of the cable system on the airplane, if desired, for convenience.\n\n2. Inspection of the Control Cable Wire Rope\n\tA. Perform a detailed visual inspection to ensure that the cable does not contact parts other than pulleys, quadrants, cable seals, or grommets installed to control the cable routing. Look for evidence of contact with other parts. Correct the condition if evidence of contact is found.\n\tNOTE: For the purposes of this procedure, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required."\n\tB. Perform a detailed visual inspection of the cable runs to detect incorrect routing, kinks in the wire rope, or other damage. Replace the cable assembly if:\n\t\t(1)\tOne cable strand had worn wires where one wire cross section is decreased by more than 40 percent (see Figure 1),\n\t\t(2)\tA kink is found, or\n\t\t(3)\tCorrosion is found.\n\tC. Perform a detailed visual inspection of the cable: To check for broken wires, rub a cloth along the length of the cable. The cloth catches on broken wires.\n\t\t(1)\tReplace the 7x7 cable assembly if there are two or more broken wires in 12 continuous inches of cable or there are three or more broken wires anywhere in the total cable assembly.\n\t\t(2)\tReplace the 7x19 cable assembly if there are four or more broken wires in 12 continuous inches of cable or there are six or more broken wires anywhere in the total cable assembly.\n\n3. Inspection of the Control Cable Fittings\n\tA. Perform a detailed visual inspection to ensure that the means of locking the joints are intact (wire locking, cotter pins, turnbuckle clips, etc.). Install any missing parts.\n\tB. Perform a detailed visual inspection of the swaged portions of swaged end fittings to detect surface cracks or corrosion. Replace the cable assembly if cracks or corrosion are found.\n\tC. Perform a detailed visual inspection of the unswaged portion of the end fitting. Replace the cable assembly if a crack is visible, if corrosion is present, or if the end fitting is bent more than 2 degrees.\n\tD. Perform a detailed visual inspection of the turnbuckle. Replace the turnbuckle if a crack is visible or if corrosion is present.\n\n4. Inspection of Pulleys\n\tA. Perform a detailed visual inspection to ensure that pulleys are free to rotate. Replace pulleys which are not free to rotate.

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 Model 757-200, -200PF, and -200CB series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on September 10, 1999 (64 FR 49105). That action proposed to require modification of the engine thrust control cable installation, and repetitive inspections to detect certain discrepancies of the cables, pulleys, pulley brackets, and cable travel; and repair, if necessary. That action also proposed to require a one-time inspection to determine the part number of thrust control cable pulleys and replacement of existing pulleys with new pulleys, if necessary.\n\nComments\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\nSupport for the Proposal\n\tOne commenter supports the proposed rule, and one commenter states that it is not affected by the rule and has no comments.\n\nRequest to Include Additional Source of Service Information\n\tOne commenter requests that the FAA cite Boeing Service Bulletin 757-30A0018, Revision 2, dated September 9, 1999, as an additional source of service information for accomplishment of the modification specified in paragraph (e) of the proposed rule.\n\tThe FAA concurs with the commenter's request. Boeing Service Bulletin 757-30A0018, Revision 2, removes an airplane that has a different routing of the window heat wire bundle (and, therefore, does not need the support bracket assembly to ensure proper clearance between the wire bundle and engine thrust control cable) from the effectivity listing. In addition, Revision 2 corrects minor errors in the accomplishment instructions. The FAA has revised paragraph (e) of the final rule to state that the paragraph is applicable to airplanes listed in Revision 2 of the service bulletin. Also, paragraph (e) has been revised to reference Revision 2 of the service bulletin, in addition to Boeing Alert Service Bulletin 757-30A0018, Revision 1, dated September 17, 1998 (which was cited in the proposal), as appropriate sources of service information.\n\nRequest to Revise Cost Impact\n\tOne commenter states that it would take approximately 18 work hours per airplane to accomplish the inspection specified in paragraph (a) of the proposed rule. The commenter also requests that the Cost Impact section include the estimated cost for replacement of phenolic pulleys with aluminum pulleys, specified in paragraph (b) of the proposed rule. The FAA concurs with the commenter's requests and has revised the Cost Impact section of the final rule in accordance with new cost data provided by the commenter and the airplane manufacturer.\n\nRequest to Revise Applicability\n\tOne commenter requests that Model 757-200PF series airplanes be removed from the applicability of the proposed AD. The commenter states that Model 757-200PF series airplanes are not listed in the effectivity of any of the Boeing service bulletins referenced in the proposed AD.\n\tThe FAA does not concur. Although Model 757-200PF series airplanes are not subject to paragraphs (c), (d), and (e) of the final rule (which reference Boeing service bulletins), these airplanes are subject to paragraphs (a) and (b). The engine installation of the Rolls-Royce Model RB211-535E4 turbofan engine on the Model 757-200 and -200PF series airplanes is identical; therefore, the same unsafe condition exists. No change to the final rule is necessary in this regard.\n\nRequest to Eliminate Repetitive Inspections\n\tOne commenter requests that the repetitive inspections of the engine thrust control cables be removed from the proposed AD. The commenter states that the proposed rule addresses specific failure modes of the cables, and that once those corrective actions have been accomplished, the existing Boeing Maintenance Planning Document (MPD) inspection interval is adequate. The commenter states that the tracking and records burden of the repetitive inspections would not provide a cost-effective benefit or substantially increase safety margins. The commenter suggests that, if the FAA determines that more frequent inspections are necessary, a maintenance review board (MRB) revision would be the most appropriate means to provide for such inspections.\n\tThe FAA does not concur with the commenter's request. The corrective actions and modifications to the engine thrust control cable installation specified in paragraphs (b) through (e) of the AD do not eliminate the unsafe condition. The thrust reverser control system on this airplane model is such that, when the engine thrust control "B" cable fails during landing, it changes the position of the thrust reverser directional control valve causing the thrust reverser to stow and the engine to accelerate. The oppositeengine is unaffected by the cable failure and remains in full reverse. This severe asymmetric thrust condition during landing is the unsafe condition. None of the modifications required by this AD change the failure mode of the cable. The repetitive inspections specified in paragraph (a) of the AD are intended to detect wear and corrosion prior to cable failure. Such wear and corrosion could be caused by numerous problems, not just those addressed by the actions specified in paragraphs (b) through (e) of the AD. Furthermore, a revision to the MRB report would not adequately address the unsafe condition. The MRB process allows for extension of inspection intervals, on an operator-by-operator basis, based on the rate of discrepancies identified in previous inspections. The discrepancies detected during the repetitive inspections would not necessarily be chronic problems but could be induced by unrelated airplane configuration changes near the cable run. No change to the final rule is necessary in this regard.\n\nRequest to Extend Repetitive Inspection Interval\n\tOne commenter requests that the interval for the repetitive inspections specified in paragraph (a) of the proposed rule be extended to an interval coinciding with a "2C" check. The commenter states that this is what is currently required by the Boeing MPD.\n\tThe FAA does not concur. There have been two engine thrust control cable failures on Model 757 series airplanes. One event was described in the NPRM. Another event, which the FAA became aware of shortly before the NPRM was released, occurred in January 1999. There was no evidence in these events that the operators were not following the Boeing MPD recommendation for thrust control cable inspections every "2C" check. Given this experience and the possibly catastrophic effect of a thrust control cable failure, the FAA has determined that it is necessary to require more frequent inspections of the cable installation. Therefore, this AD requires the cable inspection at an interval coinciding approximately with a "C" check for the majority of the affected fleet. No change to the final rule is necessary in this regard.\n\tIn addition, two commenters request that the repetitive interval for the inspections specified in paragraph (a) of the proposed rule be extended. The commenters suggest intervals that would coincide with the commenters' own "C" check intervals. One commenter states that the proposed interval would require special scheduling and would create an economic burden. The other commenter notes that the FAA stated in the proposed rule that it is the FAA's intent that the inspections be performed during a regular scheduled maintenance visit.\n\tThe FAA does not concur with the commenters' request to extend the compliance time. In developing an appropriate compliance time for this action, the FAA considered not only the practical aspect of accomplishing the inspections at an interval of time that parallels normal scheduled maintenance for the majority of affected operators, but the possible failure modes of the engine thrust control cables. In consideration of these items, as well as the in-service failures of the cables described previously, the FAA has determined that 24 months or 6,000 flight hours, whichever occurs first, represents an appropriate interval of time allowable wherein the inspections can be accomplished during scheduled maintenance intervals for the majority of affected operators, and an acceptable level of safety can be maintained. No change to the final rule is necessary in this regard.\n\nRequest to Eliminate One-Time Inspection\n\tOne commenter requests that paragraph (b) of the proposed rule, which requires a one-time inspection of the engine thrust control cable pulleys in the struts and replacement of any phenolic pulleys with aluminum pulleys, be removed. Instead, the commenter suggests that the phenolic pulleys be replaced with aluminum pulleys only if damage is detected during the repetitive inspections specified in paragraph (a) of the proposed rule. The commenter states that the repetitive inspections would preclude the elapse of a significant time period of operation with a seized pulley and that a seized pulley would be identified before any significant cable wear could occur. \n\tThe FAA does not concur. Although the in-service problems with the phenolic pulleys in a high-temperature environment have not resulted in an engine thrust control cable failure, the FAA has determined that there is enough variability in how airplanes in the fleet are operated, in addition to the possible catastrophic effect of a cable failure, to warrant removal of the phenolic pulleys prior to seizure. Therefore, no change to the final rule is necessary in this regard.\n\nRequest to Clarify Affected Part Numbers\n\tTwo commenters suggest that phenolic engine thrust control cable pulleys having part number (P/N) BACP30M4 in the strut be included in any requirement that specifies phenolic pulleys having P/N 65B80977-1. The commenters state that pulleys having P/N BACP30M4 are interchangeable with pulleys having P/N 65B80977-1 and are installed on many of the airplanes affected by the proposed rule.\n\tThe FAA concurs. Paragraph (b) of the final rule has been revised to include phenolic pulleys having P/N BACP30M4. The FAA has determined that this addition does not necessitate reopening of the comment period. The supplemental NPRM clearly states in the preamble that the unsafe condition is associated with any phenolic pulleys in the struts, not just those having P/N 65B80977-1. Therefore, the FAA finds that the public has had a reasonable opportunity to comment on its intent.\n\nRequest for Information on Service Information\n\tOne commenter notes that paragraph (b) of the proposed rule does not reference a service bulletin. The commenter requests information regarding the availability of service information for the actions specified in paragraph (b), and the configuration of the airplanes to which paragraph (b) applies at the time of airplane delivery to the operator. No specific change to the rule is requested.\n\tThe FAA agrees that paragraph (b) of the proposed rule does not reference a service bulletin. The airplane manufacturer has not issued a service bulletin for the Model 757 series airplane describing procedures for the actions specified in paragraph (b); however, it has published Boeing Service Letter 757-SL-004-A, dated July 21, 1997, addressing this subject. Model 757 series airplanes powered by Rolls-Royce engines and having line numbers 1 through 636 inclusive were delivered from the airplane manufacturer to the operator with phenolic pulleys installed in the struts. Airplanes having line numbers 637 and subsequent were delivered with aluminum pulleys installed in the struts. No specific change to the final rule is necessary in this regard.\n\nRequest to Extend Compliance Time for Modification\n\tOne commenter requests that the compliance time for the modification specified in paragraph (e) of the proposed rule be extended. The commenter suggests no specific compliance time. The commenter states that a single failure without sufficient evidence that the engine thrust control cable was being inspected in accordance with the Boeing MPD does not warrant regulatory action within 60 days.\n\tThe FAA does not concur with the commenter's request to extend the compliance time. In developing an appropriate compliance time for this action, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the modification. In consideration of these items, as well as a report of another airplane with contact between the window heat wire bundle and engine thrust control cables in service, the FAA has determined that 60 days represents an appropriate interval of time allowable wherein the modifications can be accomplished during scheduledmaintenance intervals for the majority of affected operators, and an acceptable level of safety can be maintained. No change to the final rule is necessary in this regard.\n\nExplanation of Other Changes to Cost Impact\n\tThe cost impact section, below, has been revised. The applicability of the AD has not changed, but because the airplane model affected by this AD is continuing to be manufactured, the number of affected airplanes has increased slightly since publication of the proposed rule. Also, the proposed rule estimated the cost of the one-time inspection for all airplanes; however, this action only applies to a limited number of airplanes.\n\nConclusion\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 with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.\n\nCost Impact\n\tThere are approximately 500 Model 757-200, -200PF, and -200CB series airplanes of the affected design in the worldwide fleet. The FAA estimates that 257 airplanes of U.S. registry will be affected by this AD.\n\tFor all airplanes, it will take approximately 18 work hours per airplane to accomplish the required inspection to verify the integrity of the thrust control cables, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection required by this AD on U.S. operators is estimated to be $277,560, or $1,080 per airplane, per inspection cycle.\n\tFor airplanes required to accomplish the one-time inspection to determine the part number of the thrust control cable pulleys (142 U.S.-registered airplanes), it will take approximately 1 work hour per airplane, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection required by this AD on U.S. operators is estimated to be $8,520, or $60 per airplane.\n\tShould an operator be required to accomplish the pulley replacement, it will take approximately 16 work hours per airplane, at an average labor rate of $60 per work hour. Required parts will cost approximately $2,224 per airplane. Based on these figures, the cost impact of this inspection required by this AD on U.S. operators is estimated to be $3,184 per airplane.\n\tFor airplanes identified in Boeing Service Bulletin 757-76-1 (8 U.S.-registered airplanes), it will take approximately 2 work hours per airplane to accomplish the required guide bracket removal, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this replacement required by this AD on U.S. operators is estimated to be $960, or $120 per airplane.\n\tFor airplanes identified in Boeing Service Bulletin 757-76-0005 (14 U.S.-registered airplanes), it will take approximately 14 work hours per airplane to accomplish the required replacement, atan average labor rate of $60 per work hour. Required parts will cost approximately $1,410 per airplane. Based on these figures, the cost impact of this replacement required by this AD on U.S. operators is estimated to be $31,500, or $2,250 per airplane.\n\tFor airplanes identified in Boeing Alert Service Bulletin 757-30A0018, Revision 1 (167 U.S.-registered airplanes), it will take approximately 2 work hours per airplane to accomplish the required installation and adjustment, at an average labor rate of $60 per work hour. Required parts will cost approximately $192 per airplane. Based on these figures, the cost impact of this installation and adjustment required by AD on U.S. operators is estimated to be $52,104, or $312 per airplane.\n\tThe 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\nRegulatory Impact\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\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\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.\nAdoption of the Amendment \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: \nPART 39 - AIRWORTHINESS DIRECTIVES\n\t1. The authority citation for part 39 continues to read as follows:\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n§ 39.13 (Amended)\n\t2. Section 39.13 is amended by adding the following new airworthiness directive:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Kathrine Rask, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1547; fax (425) 227-1181.