AD 2000-10-17

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires inspections, tests, and certain modifications of the thrust reverser control and indication system and wiring on each engine, and corrective action, if necessary. This amendment also requires installation of a terminating modification, and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. This amendment is prompted by the results of a safety review, which revealed that in-flight deployment of a thrust reverser could result in significant reduction in airplane controllability. The actions specified by this AD are intended to ensure the integrity of the fail-safe features of the thrust reverser system by preventing possible failure modes, which could result in inadvertent deployment of a thrust reverser during flight, and consequent reduced controllability of the airplane.

Final rule.

2000-10-17 BOEING: Amendment 39-11741. Docket 99-NM-65-AD. \n\n\tApplicability: Model 747 series airplanes equipped with Pratt & Whitney JT9D-70 series 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 (g) 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 inadvertent deployment of a thrust reverser during flight and consequent reduced controllability of the airplane, accomplish the following: \n\nInspection/Repair \n\n\t(a)\tWithin 200 flight hours or 50 flight cycles after the effective date of this AD, whichever occurs later: Inspect the thrust reverser wiring on each engine to detect discrepancies, in accordance with Boeing Service Bulletin 747-78A2149, Revision 1, dated May 9, 1996, or Revision 2, dated August 29, 1996. Prior to further flight, repair any discrepancy, in accordance with the service bulletin. \n\nModification and Tests \n\n\t(b)\tWithin 5,000 flight hours or 500 flight cycles after the effective date of this AD, whichever occurs later: Accomplish the thrust reverser wiring modification on each engine in accordance with Boeing Service Bulletin 747-78A2149, Revision 1, dated May 9, 1996, or Revision 2 dated August 29, 1996. \n\n\t\t(1)\tConcurrent with accomplishment of Boeing Service Bulletin 747-78A2149, Revision 1 or Revision 2: Accomplish the modification of the thrust reverser control system wiring specified in Rohr Service Bulletin TBC-CNS 78-32, Revision 1, dated August 20, 1996. \n\n\t\t(2)\tPrior to further flight following accomplishment of the modification specified in paragraphs (b) and (b)(1): Perform an operational test of the thrust reverser wiring on each engine to detect discrepancies in accordance with Boeing Service Bulletin 747-78A2149, Revision 1, dated May 9, 1996, or Revision 2 dated August 29, 1996. Prior to further flight, correct any discrepancy detected, in accordance with the service bulletin. \n\nRepetitive Inspections and Tests \n\n\t(c)\tPerform the inspections and tests of the thrust reverser control and indication system to detect discrepancies at the times specified in paragraphs (c)(1) and (c)(2) of this AD, in accordance with Boeing Alert Service Bulletin 747-78A2159, dated May 18, 1995. \n\n\t\t(1)\tWithin 90 days after the effective date of this AD,inspect in accordance with Part III, "1,000 Flight Hour Inspections" of the Accomplishment Instructions of the alert service bulletin. Repeat at intervals not to exceed 1,000 flight hours until accomplishment of paragraph (f) of this AD. \n\n\t\t(2)\tWithin 1,500 flight hours or 4 months after the effective date of this AD, whichever occurs later, inspect and test in accordance with Part III, "18 Month Thrust Reverser System Checks" of the Accomplishment Instructions of the alert service bulletin. Repeat at intervals not to exceed 18 months until accomplishment of paragraph (e) of this AD. \n\nCorrective Actions \n\n\t(d)\tIf any inspection or test required by paragraph (c) of this AD cannot be successfully performed as specified in the referenced service bulletin, or if any discrepancy is detected during any inspection or test, prior to further flight, repair in accordance with Boeing Alert Service Bulletin 747-78A2159, dated May 18, 1995. Additionally, prior to further flight, any failed inspection or test required by paragraph (c) of this AD must be repeated and successfully accomplished. \n\nTerminating Action \n\n\t(e)\tAccomplish the requirements of paragraphs (e)(1) and (e)(2) of this AD at the times specified in those paragraphs. Accomplishment of these actions constitutes terminating action for the repetitive inspections and tests required by paragraph (c) of this AD. \n\n\t\t(1)\tWithin 36 months after the effective date of this AD: Install an additional locking system on each engine thrust reverser in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-78-2153, Revision 1, dated November 27, 1996. \n\n\t\t(2)\tPrior to or concurrent with accomplishment of Boeing Service Bulletin 747-78-2153, Revision 1: Accomplish the installation of provisional wiring for the locking system on the thrust reversers in accordance with Boeing Service Bulletins 747-78-2135, dated August 31, 1995; and 747-78A2149, Revision 1, dated May 9, 1996, or Revision2, dated August 29, 1996. Additionally, concurrent with accomplishment of Boeing Service Bulletin 747-78-2153, Revision 1, accomplish the installation of the provisional wiring described previously in accordance with Rohr Service Bulletin TBC-CNS 78-33, Revision 1, dated August 20, 1996. \n\nRepetitive Functional Tests \n\n\t(f)\tWithin 4,000 hours time-in-service after accomplishment of paragraph (e) of this AD: Perform a functional test to detect discrepancies of the additional locking system on each thrust reverser, in accordance with Appendix 1 (including Figures 1 and 2) of this AD. Prior to further flight, correct any discrepancy detected, in accordance with the procedures described in the Boeing 747 Airplane Maintenance Manual. Repeat the functional test thereafter at intervals not to exceed 4,000 hours time-in-service. \n\nAlternative Methods of Compliance \n\n\t(g)\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 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 Permit \n\n\t(h)\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(i)\tExcept as provided by paragraph (f) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-78A2149, Revision 1, dated May 9, 1996; Boeing Service Bulletin 747-78A2149, Revision 2, dated August 29, 1996; Boeing Alert Service Bulletin 747-78A2159, dated May 18, 1995; Boeing Service Bulletin 747-78-2135, dated August 31, 1995; Boeing Service Bulletin 747-78-2153, Revision 1, dated November 27, 1996; Rohr Service Bulletin TBC-CNS 78-32, Revision 1, dated August 20, 1996; and Rohr Service Bulletin TBC-CNS 78-33, Revision 1, dated August 20, 1996; as applicable. Rohr Service Bulletin TBC-CNS 78-32, Revision 1, dated August 20, 1996 contains the following list of effective pages: \n\n\nPage Number\nRevision Level Shown on Page\nDate Shown on Page\n1, 3, 5-8, 10-11, 13-14, 16-18\n1\nAugust 20, 1996\n2, 4, 9, 12, 15\nOriginal\nMay 25, 1995\n\nRohr Service Bulletin TBC-CNS 78-33, Revision 1, dated August 20, 1996 contains the following list of effective pages: \n\n\nPage Number\nRevision Level Shown on Page\nDate Shown on Page\n1, 3-55\n1\nAugust 20, 1996\n2\nOriginal\nDecember 11, 1995\n\nThis 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(j)\tThis amendment becomes effective on June 30, 2000. \n\n\nAPPENDIX 1.\nTHRUST REVERSER SYNC-LOCK INTEGRITY TEST\n\n\n1.\tGeneral\nA.\tEquipment and Materials\n\n(1)\tThrust reverser flex drive adapter - 196K8004-1 or 196K8004-3; Rohr Industries, Inc., Chula Vista, California 92012.\n\n2.\tThrust Reverser Sync-Lock Integrity Test\nB.\tPrepare for the thrust reverser sync lock test.\n\n(1)\tOpen applicable T/R CONT & BLEED SYS circuit breaker on P12 circuit breaker panel.\n\n(2)\tOpen fan cowl doors (Ref 71-11-02, Maintenance Practices).\n\n(3)\tCheck that forward and aft circumferential latches and all tension latches are engaged and locked.\n\n(4)\tDepress drive unit latch operating arm and retain by engaging latch arm (detail C).\n\n(5)\tDisengage stow latch hook on left and right thrust reversers (detail D).\n\n(6)\tOn either lower slave actuator (detail B), either remove coverplate from forward drive pad or remove locking plug from lower drive pad.\n\n(7)\tMove left-hand sync-lock lever to the unlocked position.\n\n(8)\tUsing appropriate drive adapter (196K8004-1 at forward drive pad or 196K8004-3 at lower drive pad), attempt to manually deploy sleeves.\n\nCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 75 POUND-INCHES TO THE ACTUATOR; A GREATER TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.\n\n(9)\tIf sleeves move, replace the right-hand sync-lock.\n\n(10)\tMove left-hand sync-lock lever to the locked position.\n\n(11)\tMove right-hand sync-lock lever to the unlocked position.\n\n(12)\tRepeat step (8) above.\n\n(13)\tIf sleeves move, replace the left-hand sync-lock.\n\n(14)\tMove left-hand sync-lock lever to the unlocked position.\n\n(15)\tRotate actuator gearshaft to fully stow the sleeves.\n\n(16)\tWhen translating sleeves reach stowed position, check that stow latch hooks have engaged fixed hooks on both sides (detail D).\n\n(17)\tDepress latch operating arm and disengage latch arm (detail C); allow latch arm to raise.\n\n(18)\tAfter releasing arm, verify latch engagement by attempting to rotate feedback gear on drive unit using 1/4-inch square drive; gear shall not rotate in excess of 0.1 of a turn.\n\nCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 25 POUND-INCHES ON FEEDBACK GEAR; A GREATER TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.\n\n(19)\tAs applicable, install locking plug (with square section facing away from drive pad) or coverplate on actuator drive pad. Secure plug or plate with bolts tightened to 50-70 pound-inches.\n\n(20)\tMove both left- and right-hand sync-lock levers to the locked position.\n\n(21)\tClose fan cowl doors (Ref 71-11-02, Maintenance Practices).\n\n(22)\tClose T/R CONT & BLEED SYS circuit breaker.\n\n(23)\tRepeat the sync-lock integrity test on all remaining thrust reversers

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 747 series airplanes was published in the Federal Register on February 4, 2000 (65 FR 5459). That action proposed to require inspections, tests, and certain modifications of the thrust reverser control and indication system and wiring on each engine, and corrective action, if necessary. That action also proposed to require installation of a terminating modification, and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \n\nConclusion \n\n\tThe FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 7 Model 747 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 6 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 32 work hours (8 work hours per engine) per airplane, to accomplish the required thrust reverser inspection, modification, and test, described in 747-78A2149, Revision 1, or Revision 2, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $11,520, or $1,920 per airplane. \n\n\tIt will take approximately 8 work hours (2 work hours per engine) per airplane, to accomplish the required 1,000- flight-hour inspections described in Boeing Service Bulletin 747-78A2159, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $2,880, or $480 per airplane, per inspection cycle. \n\n\tIt will take approximately 20 work hours (5 work hours per engine) per airplane, to accomplish the required 18- month thrust reverser system checks described in Boeing Service Bulletin 747-78A2159, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the test required by this AD on U.S. operators is estimated to be $7,200, or $1,200 per airplane, per test cycle. \n\n\tIt will take approximately 544 work hours per airplane, to accomplish the required provisional wiring, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $195,840, or $32,640 per airplane. \n\n\tIt will take approximately 593 work hours per airplane, to accomplish the required sync lock installation, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the installation required by this AD on U.S. operators is estimated to be $213,480, or $35,580 per airplane. \n\n\tIt will take approximately 4 work hours per airplane, to accomplish the required functional test of the additional locking system, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the test required by this AD on U.S. operators is estimated to be $1,680, or $240 per airplane, per test cycle. \n\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\n\tThe regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \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 delegatedto me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\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: