Airworthiness Directive · Amendment 39-11540 · Boeing Model 747-400 Series Airplanes Equipped with Rolls-Royce RB211-524G/H and RB211-524G-T/H-T Engines
Boeing Model 747-400 Series Airplanes Equipped with Rolls-Royce RB211-524G/H and RB211-524G-T/H-T Engines
Model 747-400 series airplanes equipped with Rolls-Royce RB211-524G/H engines, and RB211-524G-T/H-T engines; certificated in any category.
Note 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 (d) 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.
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 series airplanes. This action requires installation of a modification of the thrust reverser control and indication system and wiring on each engine; and repetitive operational checks 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 a significant reduction in airplane controllability. The actions specified in 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.
To prevent inadvertent deployment of a thrust reverser during flight and consequent reduced controllability of the airplane, accomplish the following:
(a) Accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) of this AD at the times specified in those paragraphs. Accomplishment of these actions, or installation of an additional locking system during production in accordance with production equivalent PRR 81000-39, constitutes terminating action for the inspections and tests required by paragraph (c) of AD 94-15-05, amendment 39-8976.
(1) Within 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 747-78-2158, Revision 2, dated July 29, 1999.
Note 2: Modifications accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 747-78-2158, Revision 1, dated January 22, 1998; are considered acceptable for compliance with the applicable action specified in this amendment.
(2) Concurrent with the installation required by paragraph (a)(1) of this AD, accomplish the requirements of paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
(i) Accomplish the additional procedures for installation of an additional locking system on each engine thrust reverser in accordance with Rolls-Royce Service Bulletin RB.211-78-9601, Revision 5, dated February 20, 1998.
(ii) Install a thrust reverser translating cowl assembly seal support in accordance with Rolls-Royce Service Bulletin RB.211-78-B207, dated November 19, 1994.
(3) Prior to or concurrent with the installation required by paragraph (a)(1) of this AD, accomplish the requirements of paragraphs (a)(3)(i), (a)(3)(ii), (a)(3)(iii), and (a)(3)(iv) of this AD:
(i) Modify the fuel temperature indicating system in accordance with Boeing Service Bulletin 747-73-2052, Revision 1, dated April 23, 1992; and Rolls-Royce Service Bulletin RB.211-71-9043, dated May 4, 1990. Prior to or concurrent with accomplishment of Boeing Service Bulletin 747-73-2052, Revision 1: Modify the central maintenance computer system (CMCS) hardware and software in accordance with Boeing Service Bulletin 747-45-2007, dated March 29, 1990; and Boeing Service Bulletin 747-45-2016, Revision 1, dated May 2, 1996.
(ii) Install the provisional wiring for the locking system on the thrust reversers in accordance with Boeing Service Bulletin 747-78-2121, dated October 29, 1992; and 747-78-2157, Revision 2, dated November 26, 1997.
(iii) Modify the integrated display system (IDS) software in accordance with Boeing Service Bulletin 747-31-2246, dated May 2, 1996.
(iv) Install engine provisions to accommodate the installation of an additional locking system on each engine thrust reverser in accordance with Rolls-Royce Service Bulletin RB.211-71-9600, Revision 8, dated May 24, 1996; and RB.211-71-9608, Revision 3, dated April 18, 1997.
(b) Within 3,000 flight hours after accomplishing the requirements of paragraph (a) of this AD, or within 1,000 flight hours after the effective date of this AD, whichever occurs later: Perform operational checks of the number 2 and number 3 gearbox locks and of the air motor brake, in accordance with the procedures described in Appendix 1 (including Figure 1) of this AD. Repeat the operational checks thereafter at intervals not to exceed 3,000 flight hours.
(c) If any operational check required by paragraph (b) of this AD cannot be successfully performed as specified in the procedures described in Appendix 1 (including Figure 1) of this AD, or if any discrepancy is detected during any operational check, prior to further flight, repair in accordance with the procedures specified in the Boeing 747 Airplane Maintenance Manual. Additionally, prior to further flight, any failed operational check required by paragraph (b) of this AD must be repeated and successfully accomplished. Repeat the operational checks thereafter at intervals not to exceed 3,000 flight hours.
