Airworthiness Directives; Boeing Model 747-400 Series Airplanes Equipped with Pratt & Whitney PW4000 Series Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; correction.

SUMMARY:

This document corrects information in an existing airworthiness directive (AD) that applies to certain Boeing Model 747-400 series airplanes. That AD currently requires installation of a modification of the thrust reverser control and indication system and wiring on each engine; and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. This document publishes Appendix 1, which was referenced in, but inadvertently omitted from, the existing AD. Appendix 1 describes procedures for a functional test to detect discrepancies of the additional locking system on each engine thrust reverser. This correction is necessary to ensure that operators have the procedures necessary to perform the required functional test.

DATES:

Effective July 28, 2000.

The incorporation by reference of certain publications listed in the regulations was approved previously by the Director of the Federal Register as of July 28, 2000 (65 FR 39079, June 23, 2000).

FOR FURTHER INFORMATION CONTACT:

Larry Reising, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2683; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

On June 14, 2000, the Federal Aviation Administration (FAA) issued AD 2000-12-21, amendment 39-11799 (65 FR 39079, June 23, 2000), which applies to certain Boeing Model 747-400 series airplanes. That AD requires installation of a modification of the thrust reverser control and indication system and wiring on each engine; and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. That AD was 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 required by that 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.

Need for the Correction

Since the issuance of that AD, the FAA discovered that Appendix 1 was inadvertently omitted from the final version of the AD. Appendix 1 is referenced in paragraph (b) of the AD as the appropriate source of procedures for the functional test to detect discrepancies of the additional locking system on each engine thrust reverser. Appendix 1 was published in the notice of proposed rulemaking (NPRM), which preceded the final rule. No comments affecting the procedures described in Appendix 1 were received in response to the NPRM.

The FAA has determined that a correction to AD 2000-12-21 is necessary. The correction will add Appendix 1 to the existing AD to ensure that operators have the procedures necessary to perform the functional test required by paragraph (b) of the AD.

Correction of Publication

This document adds Appendix 1 and correctly adds the AD as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13).

The AD is reprinted in its entirety for the convenience of affected operators. The effective date of the AD remains July 28, 2000.

Since this action only adds procedures to make it possible for operators to accomplish the AD, it has no adverse economic impact and imposes no additional burden on any person. Therefore, the FAA has determined that notice and public procedures are unnecessary.

List of Subject in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Correction

Accordingly, 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:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. Section 39.13 is amended by correctly adding the following airworthiness directive (AD):

2000-12-21 Boeing: Amendment 39-11799. Docket 99-NM-66-AD.

Applicability: Model 747-400 series airplanes equipped with Pratt & Whitney PW4000 series 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent inadvertent deployment of a thrust reverser during flight and consequent reduced controllability of the airplane, accomplish the following:

Modifications

(a) For airplanes identified in Boeing Service Bulletin 747-78-2155, Revision 2, dated November 5, 1998: Accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD at the times specified in those paragraphs. Accomplishment of these actions constitutes terminating action for the inspections and tests required by paragraph (a) 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 747-78-2155, Revision 2, dated November 5, 1998.

Note 2:

Installations accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 747-78-2155, Revision 1, dated January 30, 1997, are considered acceptable for compliance with paragraph (a)(1) of this AD.

(2) Prior to or concurrent with the installation required by paragraph (a)(1) of this AD, accomplish the requirements of paragraphs (a)(2)(i), (a)(2)(ii), and (a)(2)(iii) of this AD:

(i) Modify the central maintenance computer system hardware and software in accordance with Boeing Service Bulletin 747-45-2016, Revision 1, dated May 2, 1996.

(ii) Modify the integrated display system software in accordance with Boeing Service Bulletin 747-31-2245, dated June 27, 1996.

(iii) Install the provisional wiring for the locking system on the thrust reversers in accordance with Boeing Service Bulletin 747-78-2154, Revision 3, dated December 11, 1997.

Note 3:

Installations accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 747-78-2154, Revision 1, dated November 2, 1995, and Revision 2, dated October 31, 1996, are considered acceptable for compliance with paragraph (a)(2)(iii) of this AD.

Repetitive Functional Tests

(b) Within 4,000 hours time-in-service after accomplishment of paragraph (a) of this AD, or production equivalent; or within 1,000 hours time-in-service after the effective date of this AD, whichever occurs later: Perform a functional test to detect discrepancies of the additional locking system on each engine thrust reverser, in accordance with Appendix 1 of this AD. Prior to further flight, correct any discrepancy detected and repeat the functional test of that repair, in accordance with the procedures described in the Boeing 747-400 Airplane Maintenance Manual. Repeat the functional test thereafter at intervals not to exceed 4,000 hours time-in-service.

Terminating Action Airplanes Having Line Numbers 1067 and Higher

(c) For airplanes having line numbers 1067 and higher on which the intent of Boeing Service Bulletin 747-78-2155, Revision 2, dated November 5, 1998, was accomplished during production: Accomplishment of the repetitive functional tests required by paragraph (b) of this AD constitutes terminating action for the repetitive inspections and functional tests required by paragraph (a) of AD 94-15-05, amendment 39-8976.

Alternative Methods of Compliance

(d) An 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.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(e) Special 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.

Incorporation by Reference

(f) Except as provided by paragraph (b) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-78-2155, Revision 2, dated November 5, 1998; Boeing Service Bulletin 747-45-2016, Revision 1, dated May 2, 1996; Boeing Service Bulletin 747-31-2245, dated June 27, 1996; or Boeing Service Bulletin 747-78-2154, Revision 3, dated December 11, 1997; as applicable. This incorporation by reference was approved previously by the Director of the Federal Register as of July 28, 2000 (65 FR 39079, June 23, 2000). 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.

Effective Date

(g) The effective date of this amendment remains July 28, 2000.

Appendix 1.—Thrust Reverser Sync-Lock—Adjustment/Test

1. General

A. There are two sync-locks for each engine thrust reverser. The sync-lock is installed on the lower non-locking hydraulic actuator of each thrust reverser sleeve.

B. The Thrust Reverser Sync-Lock Integrity Test has two tasks:

(1) The first task does a test of the electrical circuit which controls the operation of the sync-lock on each thrust reverser sleeve.

(2) The second task does a test of the mechanical function of the sync-lock on each thrust reverser sleeve.

C. The thrust reverser sync-lock is referred to as “the sync-lock” in this procedure.

2. Thrust Reverser Sync-Lock Integrity Test

A. Equipment—Multi-meter, Simpson 260 or equivalent—commercially available

B. Prepare to do the integrity test for the sync-locks

(1) Supply electrical power

(2) For the applicable engine, make sure these circuit breakers on the Main Power Distribution Panel P6, are closed:

6F12 ENG 1 T/R IND

6E12 ENG 2 T/R IND

6D12 ENG 3 T/R IND

6C12 ENG 4 T/R IND

6F13 ENG 1 T/R CONT

6E13 ENG 2 T/R CONT

6D13 ENG 3 T/R CONT

6C13 ENG 4 T/R CONT

6F11 ENG 1 T/R LOCK CONT

6E11 ENG 2 T/R LOCK CONT

6D11 ENG 3 T/R LOCK CONT

6C11 ENG 4 T/R LOCK CONT

(3) Open the fan cowl panels for the applicable engine.

C. Do the electrical integrity test for the sync-locks.

(1) Do these steps, for the applicable engine, to make sure there are no “hot” short circuits in the electrical system which can accidentally supply power to the sync-locks:

(a) Remove the electrical connector, D20194, from the sync-lock, V170, on the left sleeve of the thrust reverser.

(b) Remove the electrical connector, D20196, from the sync-lock, V171, on the right sleeve of the thrust reverser.

(c) Use a multi-meter on the plug end of the applicable electrical connector to make sure that these conditions are correct:

(d) If you find the correct conditions, do the mechanical integrity test for the sync-locks.

(e) If you did not find these conditions to be correct, you must do these steps:

(1) Make a careful visual inspection of all the electrical wires and connectors between the sync-lock and its power circuit.

(2) Repair all the unserviceable electrical wire and connectors that you find.

(3) Use the multi-meter again to make sure there are no “hot” short circuits in the electrical system which can accidentally supply power to the sync-locks.

D. Do the mechanical integrity test for the sync-locks.

(1) Supply hydraulic power.

WARNING: MAKE SURE ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE AREA BEHIND EACH THRUST REVERSER. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR IF THE SYNC-LOCKS DO NOT OPERATE CORRECTLY AND THE THRUST REVERSER EXTENDS.

(2) Move the applicable reverser thrust lever aft to try to extend the thrust reverser with hydraulic power.

Note:

If the thrust reverser sleeves do not extend, the sync-locks are serviceable. If the thrust reverser sleeves extend, the applicable sync-lock did not operate correctly.

(3) Replace the sync-lock(s) on the thrust reverser sleeve(s) that did extend when you moved the reverse thrust levers. Repeat steps 2.D.(1) and 2.D.(2) to verify that functional sync-locks are installed.

(4) Move the applicable thrust reverser lever forward to the stow position.

(5) Install the electrical connector, D20194, on the sync-lock, V170 on the left sleeve of the thrust reverser.

(6) Install the electrical connector, D20196, on the sync-lock, V171, on the right sleeve of the thrust reverser.

WARNING: MAKE SURE ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE AREA BEHIND EACH THRUST REVERSER. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR WHEN THE THRUST REVERSERS ARE EXTENDED.

(7) Move the applicable thrust reverser aft to try to extend the thrust reverser with hydraulic power.

Note:

If the thrust reverser sleeves extended, the sync-locks are serviceable. If the thrust reverser sleeves did not extend, the applicable sync-lock is not serviceable.

(8) Replace the sync-lock(s) on the thrust reverser sleeve that did not extend when you moved the reverse thrust levers. Repeat steps 2.D.(4) through 2.D.(7) to verify that functional sync-locks are installed.

(9) Repeat steps 2.A. through 2.D. for all other engine positions.

E. Put the airplane back to its usual condition.

(1) Move the reverse thrust levers forward to fully retract the thrust reversers on the applicable engine.

(2) Remove the hydraulic power if it is not necessary.

(3) Remove the electrical power if it is not necessary.

(4) Close the fan cowl panels.