94-01-10 BOEING: Amendment 39-8792. Docket 92-NM-173-AD. Supersedes AD 91-20-09, Amendment 39-8043.\n \n\tApplicability: Model 757 series airplanes equipped with Pratt and Whitney PW2000 series engines, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tNOTE 1: Paragraphs (a) and (b) of this AD restate the requirements of AD 91-20-09, Amendment 39-8043, paragraphs (a) and (b). As allowed by the phrase, "unless accomplished previously," if the requirements of AD 91-20-09 have been accomplished previously, paragraphs (a) and (b) of this AD do not require those actions to be repeated. \n\n\tNOTE 2: Paragraph (c) of this AD restates the requirement for repetitive inspections contained in paragraph (d) of AD 91-20-09, Amendment 39-8043. Paragraph (c) of this AD requires that the first inspection required by this AD must be performed within the specified repetitive inspection interval after the last inspection performed in accordance with paragraph (d) of AD 91-20-09. \n\n\tTo prevent deployment of a thrust reverser in flight and subsequent reduced controllability of the airplane, accomplish the following: \n\n\t(a)\tWithin 14 days after September 16, 1991 (the effective date of AD 91-20-09, Amendment 39-8043), accomplish either paragraph (a)(1) or (a)(2) of this AD. \n\n\t\t(1)\tAccomplish both paragraphs (a)(1)(i) and (a)(1)(ii) of this AD: \n\t\t\t(i)\tInspect the thrust reverser Directional Control Valve (DCV) assemblies of both engines to determine the solenoid-driven pilot valve's part number, in accordance with Boeing Alert Service Bulletin 757-78A0027, dated September 9, 1991.\n \n\t\t\t\t(A)\tIf any DCV has a suspect pilot valve as specified in the service bulletin, prior to further flight, replace the DCV with a DCV that has a part number of a non-suspect solenoid-driven pilot valve, in accordance with the service bulletin. \n\n\t\t\t\t(B)\tIf a DCV has a non-suspect solenoid-driven pilot valve as specified in the service bulletin, that pilot valve does not need to be replaced. \n\n\t\t\t(ii)\tPerform all tests and inspections of the engine thrust reverser control and indication system on both engines in accordance with Boeing Service Bulletin 757- 78-0025, dated September 9, 1991. Prior to further flight, correct any discrepancy found in accordance with the service bulletin. \n\n\t\t(2)\tAccomplish paragraph (a)(1) of this AD on one engine's thrust reverser and deactivate the other engine's thrust reverser, in accordance with Section 78-31-1 of Boeing Document D630N002, "Boeing 757 Dispatch Deviation Guide," Revision 8, dated January 15, 1991.\n \n\t(b)\tWithin 24 days after September 16, 1991 (the effective date of AD 91-20-09, Amendment 39-8043), the requirements of paragraph (a)(1) of this AD must be accomplished on both engines' thrust reverser systems. \n\n\t(c)\tRepeat the tests and inspections specified in paragraph (a)(1)(ii) at intervals not to exceed 3,000 flight hours, and prior to further flight following any maintenance that disturbs the thrust reverser control system. Prior to further flight, correct any discrepancy found in accordance with Boeing Service Bulletin 757-78-0025, dated September 9, 1991. \n\n\t(d)\tWithin 5 years after the effective date of this AD, install an additional thrust reverser system locking feature (sync lock installation), in accordance with Boeing Service Bulletin 757-78-0028, Revision 1, dated October 29, 1992, or Revision 2, dated January 14, 1993. \n\n\t(e)\tWithin 1,000 hours time-in-service after installing the sync lock required by paragraph (d) of this AD (either in production or by retrofit), or within 1,000 hours time-in- service after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 1,000 hours time-in-service: Perform functional tests of the sync lock in accordance with the "Thrust Reverser Sync Lock Integrity Test" procedures specified below. If any discrepancy is found during any test, prior to further flight, correct it in accordance with procedures described in the Boeing 757 Maintenance Manual. \n\n\t\t"THRUST REVERSER SYNC LOCK INTEGRITY TEST \n\n1.\tGeneral \n\tA.\tUse this procedure to test the integrity of the thrust reverser sync locks. \n\n2.\tThrust Reverser Sync Lock Test \n\tA.\tPrepare for the Thrust Reverser Sync Lock Test. \n\n\t\t(1)\tOpen the AUTO SPEEDBRAKE circuit breaker on the overhead \t\t\t\tcircuit breaker panel, P11. \n\n\t\t(2)\tDo the steps that follow to supply power to the thrust reverser system: \n\t\t\t(a)\tMake sure the thrust levers are in the idle position. \n\n\t\t\tCAUTION:\tDO NOT EXTEND THE THRUST REVERSER \t\t\t\t\t\tWHILE THE CORE COWL PANELS ARE OPEN. \t\t\t\t\tDAMAGE TO THE THRUST REVERSER AND \t\t\t\t\t\tCORE COWL PANELS CAN OCCUR. \n\n\t\t\t(b)\tMake sure the thrust reverser halves are closed. \n\t\t\t(c)\tMake sure the core cowl panels are closed. \t\t\t\t\t(d)\tPut the EEC MAINT POWER switch or the EEC POWER L \t\t\t\tand EEC POWER R switches to the ALTN position. \n\n\t\t\t(e)\tFor the left engine: \n\n\t\t\t\t1)\tPut the EEC MAINT CHANNEL SEL L switch to the \n\t\t\t\t\tAUTO position. \n\t\t\t\t2)\tPut the L ENG fire switch to the NORM position. \n\n\t\t\t(f)\tFor the right engine: \n\n\t\t\t\t1)\tPut the EEC MAINT CHANNEL SEL R switch to the \n\t\t\t\t\tAUTO position. \n\t\t\t\t2)\tPut the R ENG fire switch to the NORM position. \n\n\t\t\t(g)\tMake sure the EICAS circuit breakers (6 locations) are \t\t\t\t\tclosed. \n\n\t\t\tWARNING:\tTHE THRUST REVERSER WILL AUTOMATICALLY \n\t\t\t\t\tRETRACT IF THE ELECTRICAL POWER TO THE \n\t\t\t\t\tEEC/THRUST REVERSER CONTROL SYSTEM IS \n\t\t\t\t\tTURNED OFF OR IF THE EEC MAINT POWER \n\t\t\t\t\tSWITCH IS MOVED TO THE NORM POSITION. \t\t\t\t\tTHE ACCIDENTAL OPERATION OF THE THRUST \n\t\t\t\t\tREVERSER CAN CAUSE INJURY TO PERSONS \t\t\t\t\tOR DAMAGE TO EQUIPMENT CAN OCCUR. \n\n\t\t\t(h)\tMake sure these circuit breakers on the main power \t\t\t\t\tdistribution panel, P6, are closed: \n\n\t\t\t\t1)\tFUEL COND CONT L \n\t\t\t\t2)\tFUEL COND CONT R \n\t\t\t\t3)\tT/L INTERLOCK L \n\t\t\t\t4)\tT/L INTERLOCK R \n\t\t\t\t5)\tLEFT T/R SYNC LOCK6)\tRIGHT T/R SYNC LOCK \n\t\t\t\t7)\tL ENG ELECTRONIC ENGINE CONTROL ALTN \t\t\t\t\tPWR \n\t\t\t\t\t(if installed) \n\t\t\t\t8)\tR ENG ELECTRONIC ENGINE CONTROL ALTN \t\t\t\t\tPWR \n\t\t\t\t\t(if installed) \n\n\t\t\t(i)\tMake sure these circuit breakers on the overhead circuit \n\t\t\t\tbreaker panel, P11, are closed: \n\n\t\t\t\t1)\tAIR/GND SYS 1 \n\t\t\t\t2)\tAIR/GND SYS 2 \n\t\t\t\t3)\tLANDING GEAR POS SYS 1 \n\t\t\t\t4)\tLANDING GEAR POS SYS 2 \n\n\t\t\t(j)\tFor the left engine, make sure these circuit breakers on the \t\t\t\tP11 panel are closed: \n\n\t\t\t\t1)\tLEFT ENGINE PDIU \n\t\t\t\t2)\tLEFT ENGINE THRUST REVERSER CONT/SCAV \n\t\t\t\t\tPRESS \n\t\t\t\t3)\tLEFT ENGINE ELECTRONIC ENGINE CONTROL \n\t\t\t\t\tALTN PWR (if installed) \n\t\t\t\t4)\tLEFT ENGINE THRUST REVERSER PRI CONT 5)\n\t\t\t\t\tLEFT ENGINE THRUST REVERSER SEC CONT \n\n\t\t\t(k)\tFor the right engine, make sure these circuit breakers on the \n\t\t\t\tP11 panel are closed: \n\n\t\t\t\t1)\tRIGHT ENGINE PDIU \n\t\t\t\t2)\tRIGHT ENGINE THRUST REVERSER CONT/SCAV \n\t\t\t\t\tPRESS \n\t\t\t\t3)\tRIGHT ENGINE ELECTRONIC ENGINE CONTROLALTN PWR (if installed) \n\t\t\t\t4)\tRIGHT ENGINE THRUST REVERSER PRI CONT \n\t\t\t\t5)\tRIGHT ENGINE THRUST REVERSER SEC CONT \n\n\t\t\t(l)\tSupply electrical power. \n\n\t\t\t(m)\tRemove the pressure from the left (right) hydraulic system. \n\n\tB.\tDo the Thrust Reverser Sync Lock Test. \n\n\t\t(1)\tMove and hold the manual unlock lever on the center actuator on both \t\t\tthrust reverser sleeves to the unlock position. \n\t\t(2)\tMake sure the thrust reverser sleeves did not move. \n\t\t(3)\tMove the left (right) reverser thrust lever up and rearward to the idle \n\t\t\tdetent position. \n\t\t(4)\tMake sure both thrust reverser sleeves move aft (approximately 0.15 \t\t\tto 0.25 inch). \n\t\t(5)\tRelease the manual unlock lever on the center actuators. \n\n\n\t\tWARNING:\tMAKE SURE ALL PERSONS AND EQUIPMENT ARE \t\t\tCLEAR OF THE AREA AROUND THE THRUST REVERSER. WHEN YOU \t\tAPPLY \tHYDRAULIC PRESSURE THE THRUST REVERSER WILL EXTEND \t\tAND CAN CAUSE INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT. \n\n\t\t(6)\tPressurize the left (right) hydraulic system. \n\t\t(7)\tMake sure the thrust reverser extends. \n\t\t(8)\tMove the left (right) reverser thrust lever to the fully forward and down \n\t\t\tposition to retract the thrust reverser.\n \n\tC.\tPut the Airplane Back to its Usual Condition. \n\n\t\t(1)\tRemove hydraulic pressure. \n\t\t(2)\tClose the left and right fan cowls. \n\t\t(3)\tClose the AUTO SPEEDBRAKE circuit breaker on the P11 panel. \n\t\t(4)\tRemove electrical power if it is not necessary. \n\n\tD.\tRepeat the Thrust Reverser Sync Lock Test on the other engine." \n\n\t(f)\tInstallation of the sync lock, as required by paragraph (d) of this AD, constitutes terminating action for the requirements of paragraphs (a) through (c) of this AD. \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 3: Approvals of alternative methods of compliance issued for AD 91-20-09 constitute valid approvals for compliance with the requirements of paragraphs (a) through (c) of this AD. \n\n\tNOTE 4: 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(h)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(i)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 757- 78A0027, dated September 9, 1991; Boeing Service Bulletin 757-78-0025, dated September 9, 1991; Boeing Document D630N002, "Boeing 757 Dispatch Deviation Guide," Revision 8, dated January 15, 1991; Boeing Service Bulletin 757-78-0028, Revision 1, dated October 29, 1992; andBoeing Service Bulletin 757-78-0028, Revision 2, dated January 14, 1993. The incorporation by reference of Boeing Alert Service Bulletin 757-78A0027, dated September 9, 1991; Boeing Service Bulletin 757-78-0025, dated September 9, 1991; Boeing Document D630N002, "Boeing 757 Dispatch Deviation Guide," Revision 8, dated January 15, 1991; was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51 as of September 16, 1991 (56 FR 46725, September 16, 1991). The incorporation by reference of the remainder of the service documents listed above is 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 March 3, 1994.