AD 94-17-03

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires inspections, adjustments, and functional checks of the thrust reverser system; installation of a terminating modification; and repetitive operational checks of the gearbox locks and the air motor brake following accomplishment of the modification. This amendment is prompted by the identification of a modification that ensures that the level of safety inherent in the original type design of the thrust reverser system is further enhanced. The actions specified by this AD are intended to prevent possible discrepancies that exist in the current thrust reverser control system, which could result in an inadvertent deployment of a thrust reverser during flight.

Final rule

94-17-03 BOEING: Amendment 39-8998. Docket 92-NM-237-AD. \n\n\tApplicability: Model 767 series airplanes equipped with Rolls-Royce RB211-524 series engines, certificated in any category.\n \n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo ensure the integrity of the fail safe features of the thrust reverser system, accomplish the following: \n\n\t(a)\tWithin 30 days after October 15, 1991 (the effective date of AD 91-22-02, Amendment 39-8062), perform the inspections, adjustments, and functional checks described in Boeing Service Bulletin 767-78-0048, dated August 15, 1991, or Revision 1, dated March 26, 1992. Perform those actions in accordance with procedures described in the service bulletin. After the effective date of this AD, those actions shall be accomplished only in accordance with Revision 1 of the service bulletin. Accomplishment of the actions required by this paragraph terminates the actions required by paragraph (a) of AD 91-22-02, amendment 39-8062. \n\n\t\t(1)\tExcept as provided by paragraph (a)(2) of this AD, repeat all inspections and functional checks in accordance with the service bulletin at intervals not to exceed 3,000 flight hours. \n\n\t\t(2)\tRepeat the functional check of the grounding wire for the thrust reverser Selector Sequence Valve (SSV) in accordance with the service bulletin at intervals not to exceed 1,500 flight hours, and whenever maintenance action is taken that would disturb the SSV grounding circuit. \n\n\t(b)\tIf any of the inspections and/or functional checks required by paragraph (a) of this AD cannot be successfully performed, or if those inspections and/or functional checks result in findings that are unacceptable in accordance with Boeing Service Bulletin 767-78-0048, dated August 15, 1991, or Revision 1, dated March 26, 1992, accomplish paragraphs (b)(1) and (b)(2) of this AD. After the effective date of this AD, the actions required by paragraph (b)(2) of this AD shall be accomplished onlyin accordance with Boeing Service Bulletin 767-78-0048, Revision 1, dated March 26, 1992. \n\n\t\t(1)\tPrior to further flight, deactivate the associated thrust reverser in accordance with Section 78-31-1 of Boeing Document D630T002, "Boeing 767 Dispatch Deviation Guide," Revision 11, dated March 15, 1993. No more than one thrust reverser on any airplane may be deactivated under the provisions of this paragraph. \n\n\t\t(2)\tWithin 10 days after deactivation of any thrust reverser in accordance with this paragraph, the thrust reverser must be repaired in accordance with Boeing Service Bulletin 767- 78-0048, dated August 15, 1991, or Revision 1, dated March 26, 1992. Additionally, the inspections and/or functional checks required by paragraph (a) of this AD must be successfully accomplished; once this is accomplished, the thrust reverser must then be reactivated. \n\n\t(c)\tWithin 3 years after the effective date of this AD, install a second locking gearbox system on the left- and right-handengine thrust reversers, in accordance with Boeing Service Bulletin 767-78-0059, Revision 2, dated June 10, 1993; or Revision 3, dated January 20, 1994. \n\n\tNOTE 1: Revisions 2 and 3 of Boeing Service Bulletin 767-78-0059 reference Rolls-Royce Service Bulletins RB.211-71-9608, RB.211-71-9600, and RB.211-71-9601, and Eldec Service Bulletin 8-651-32-01 as additional sources of service information for accomplishment of the locking gearbox installation. However, the Boeing service bulletins do not specify the appropriate revision levels for those Rolls-Royce and Eldec service bulletins. The appropriate revision levels for the Rolls-Royce and Eldec service bulletins to be used in conjunction with Boeing Service Bulletin 767-78-0059 are as follows: Rolls-Royce Service Bulletin RB.211-71-9608, Revision 1, dated October 2, 1992; Rolls-Royce Service Bulletin RB.211-71-9600, Revision 4, dated February 11, 1994; Rolls-Royce Service Bulletin RB.211-71-9601, Revision 1, dated October 2, 1992;and Eldec Service Bulletin 8-651-32-01, dated January 31, 1992. \n\n\t(d)\tWithin 3,000 flight hours after accomplishing the modification required by paragraph (c) of this AD, or within 1,000 flight hours after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 3,000 flight hours; perform operational checks of the number 2 and number 3 gearbox locks and of the air motor brake in accordance with Appendix 1 (including Figure 1) of this AD. \n\n\t(e)\tAccomplishment of the modification and periodic operational checks required by paragraphs (c) and (d) of this AD constitutes terminating action for the inspections, adjustments, and functional checks required by paragraph (a) of this AD. \n\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\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\n\t(g)\tSpecial flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (FAR) (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(h)\tCertain actions shall be done in accordance with Boeing Service Bulletin 767-78-0048, Revision 1, dated March 26, 1992; and Boeing Service Bulletin 767-78-0059, Revision 2, dated June 10, 1993, or Boeing Service Bulletin 767-78-0059, Revision 3, dated January 20, 1994. The incorporation by reference of these documents was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Certain other actions shall be done in accordance with Boeing Service Bulletin 767-78-0048, dated August 15, 1991. The incorporation by reference of that document 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 October 15, 1991 (56 FR 51638). 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(i)\tThis amendment becomes effective on September 14, 1994. \n\n\nFIGURE 1\n\n\n\n\t\t\t\t\tAPPENDIX 1\n\n1.\tGearbox Lock and Air Motor Brake Test \n\n\tA.\tGeneral \n\t\t(1)\tTo do the test of the gearbox locks and air motor brake, you must do the steps that follow: \n\t\t\t(a)\tDo the deactivation procedure of the thrust reverser system. \n\t\t\t(b)\tDo the test of the air motor brake. \n\t\t\t(c)\tDo the test of the gearbox locks. \n\t\t\t(d)\tDo the activation procedure of the thrust reverser system. \n\tB.\tEquipment \n\t\t(1)\tCP30784 - INA Access Platform, Rolls-Royce \n\t\t(2)\tCP30769 - Protection Pads, Rolls-Royce \n\t\t(3)\tCP30785 - Access Stools, Rolls-Royce \n\t\t(4)\tUT1293/1 - Load Tool, Rolls-Royce (2 required) \n\tC.\tProcedure (Fig. 1). \n\n\tWARNING:\tDO THE DEACTIVATION PROCEDURE OF THE THRUST \n\tREVERSER SYSTEM, WHICH MUST INCLUDE THE INSTALLATION OF LOCK \tBARS (OR BLOCKERS), TO PREVENT THE ACCIDENTAL OPERATION OF THE THRUST REVERSER. THE ACCIDENTAL OPERATION OF THE THRUST \tREVERSER COULD CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT. \n\n\t\t(1)\tDo the deactivation procedure of the thrust reverser in the forward thrust position for ground maintenance.\n \n\t\t(2)\tUse a 0.25 inch (6.4 mm) square drive to turn the manual lock release screw to release the No. 2 and No. 3 gearbox locks. \n\n\t\tNOTE: It is not always easy to turn the manual lock release screws. This is because of a preload in the systems. To release the preload, lightly turn the manual cycle and lockout shaft in the stow direction. \n\n\t\t\t(a)\tMake sure the lock indicators are extended at gearboxes No. 2 and No. 3. \n\n\t\t(3)\tDo a test of the air motor brake: \n\t\t\t(a)\tIF YOU USE THE LOAD TOOLS; \n\t\t\t\tTry to move the translating cowl in the extend direction as follows: \n\t\t\t\t1)\tRemove the lock bars that you installed in the deactivation procedure. \n\t\t\t\t2)\tInstall the load tools through the cutouts and into the No. 2 and No. 3 gearboxes. \n\t\t\t\t3)\tAttach the torque wrenches to the load tools. \n\t\t\t\t4)\tTry to move the translating cowl in the extend direction. \n\t\t\t(b)\tIF YOU DO NOT USE THE LOAD TOOLS; \n\t\t\t\tTry to move the translating cowl in the extend direction as \n\t\t\t\tfollows: \n\t\t\t\t1)\tRemove the lock bars that you installed in the \n\t\t\t\t\tdeactivation procedure. \n\t\t\t\t2)\tPut the 0.25 inch (6.4 mm) square drive extensions into the manual cycle and lockout shaft at the No. 2 andNo. 3 gearboxes. \n\t\t\t\t\ta)\tAttach the standard drive tools. \n\t\t\t\t3)\tTry to move the translating cowl in the extend direction. \n\t\t\t(c)\tIf the translating cowl moves, replace the air motor and shutoff valve. \n\t\t(4)\tDo a test of the gear box locks: \n\n\t\tNOTE:\tThe steps that follow are for the No. 3 gearbox. Then, do these steps again for the No. 2 gearbox. \n\t\t\t(a)\tInstall the lock bars in the manual cycle and lockout shafts at the No. 2 and No. 3 gearboxes. \n\t\t\t(b)\tInstall the INA access platform in the exhaust mixer duct. \n\t\t\t(c)\tInstall the protection pads and the access stools. \n\t\t\t(d)\tRelease the air motor brake: \n\t\t\t\t1)\tOpen the air motor access and pressure relief panel. \n\t\t\t\t2)\tPull the air motor brake release handle forward and \t\t\t\t\tturn it counterclockwise to lock the handle in its position. \n\t\t\t(e)\tTurn the manual lock release screw clockwise to engage the \t\t\t\tNo. 3 gearbox lock. \n\t\t\t\t1)\tMake sure that the lock indicator is retracted (under \t\t\t\t\tthe surface) at gearbox No. 3. \n\t\t\t(f)\tMake sure No. 2 gearbox lock is released. \n\t\t\t\t1)\tMake sure the lock indicator is extended at gearbox \t\t\t\t\tNo. 2. \n\t\t\t(g)\tIF YOU USE THE LOAD TOOLS; \n\t\t\t\t\tDo a check of the lock dogs as follows: \n\t\t\t\t1)\tRemove the lock bars from the No. 2 and No. 3 \t\t\t\t\t\tgearboxes. \n\t\t\t\t2)\tInstall the load tool through the cutout and into the No. \t\t\t\t\t3 gearbox. \n\t\t\t\t3)\tAttach the torque wrench to the load tool. \n\n\n\tCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 30 \n\tPOUND-INCHES (3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCK OUT SHAFT. A LARGER \tTORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM. \n\n\t\t\t\t4)\tApply a torque counterclockwise through the manual \n\t\t\t\t\twind position of the No. 3 gearbox. \n\t\t\t\t\ta)\tIf the translating cowl does not move, the lock \t\t\t\t\t\tbar touched one of the two lock dogs. \n\t\t\t\t\tb)\tIf the translating cowl moved, lock the thrust \n\t\t\t\t\t\treverser until the No. 3 gearbox is replaced. \n\t\t\t\t5)\tTurn the manual lock release screw \t\t\t\t\t\t\tcounterclockwise to release the gearbox lock. \n\t\t\t\t\ta)\tMake sure that the indication rod comes out \t\t\t\t\t\tof the No. 3 gearbox. \n\t\t\t\t6)\tTurn the manual cycle and lockout shaft \n\t\t\t\t\tcounterclockwise a 1/4 of a turn. \n\t\t\t\t7)\tTurn the manual lock release screw clockwise to \n\t\t\t\t\tengage the No. 3 gearbox lock. \n\t\t\t\t\ta)\tMake sure that the indication rod is fully \n\t\t\t\t\t\tretracted (under the surface). \n\n\n\tCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 30 \n\tPOUND-INCHES (3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A GREATER \tTORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM. \n\n\t\t\t\t8)\tApply a torque counterclockwise through the manual \n\t\t\t\t\twind position of the No. 3 gearbox. \n\t\t\t\t\ta)\tIf the manual cycle and lockout shaft can not be turned more than \t\t\t\t\t\t\tapproximately 1/4 turn, the second lock dog is serviceable. \n\t\t\t\t\tb)\tIf the manual cycle and lockout shaft can be \n\t\t\t\t\t\tturned more than approximately 1/4 turn, the \n\t\t\t\t\t\tsecond lock dog is unserviceable. Lock thethrust reverser until the No. 3 gearbox is \n\t\t\t\t\t\treplaced. \n\n\t\t\t\t\tNOTE:\tThe two lock dogs are found 1/2 turn apart when you use the manual cycle and lockout shaft. If necessary, do the check again to make sure that the lock dogs are serviceable.\n \n\t\t\t\t9)\tDo the procedure given above for the No. 2 gearbox \n\t\t\t\t\tlock. \n\t\t\t(h)\tIF YOU DO NOT USE THE LOAD TOOLS; \n\t\t\t\t\tDo a check of the lock dogs as follows: \n\t\t\t\t1)\tRemove the lock bars from the No. 2 and No. 3 \n\t\t\t\t\tgearboxes. \n\t\t\t\t2)\tPut the 0.25 inch (6.4 mm) square drive extensions \t\t\t\t\tinto the manual cycle and lockout shaft at the No. 2 and No. 3 gearboxes. \n\t\t\t\t\ta)\tAttach the standard drive tools. \n\n\n\tCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 30 \n\tPOUND-INCHES (3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A LARGER \tTORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM. \n\n\t\t\t\t3)\tApply a torque counterclockwise through the manual \n\t\t\t\t\twind position of the No. 3 gearbox. \n\t\t\t\t\ta)\tIf the translating cowl does not move, the lock \n\t\t\t\t\t\tbar touched one of the two lock dogs. \n\t\t\t\t\tb)\tIf the translating cowl moved, lock the thrust \n\t\t\t\t\t\treverser until the No. 3 gearbox is replaced. \n\t\t\t\t4)\tTurn the manual lock release screw \t\t\t\t\t\t\tcounterclockwise to release the gearbox lock. \n\t\t\t\t\ta)\tMake sure that the indication rod comes out \t\t\t\t\t\tof the No. 3 gearbox. \n\t\t\t\t5)\tTurn the manual cycle and lockout shaft \t\n\t\t\t\t\tcounterclockwise a 1/4 of a turn. \n\t\t\t\t6)\tTurn the manual lock release screw clockwise to \n\t\t\t\t\tengage the No. 3 gearbox lock. \n\t\t\t\t\ta)\tMake sure that the indication rod is fully \n\t\t\t\t\t\tretracted (under the surface). \n\n\n\tCAUTION:\tDO NOT APPLY A TORQUE LOAD OF MORE THAN 30 \n\tPOUND-INCHES (3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A GREATER \tTORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM. \n\n\n\t\t\t\t7)\tApply a torque counterclockwise through the manual \t\t\t\t\twind position of the No. 3 gearbox. \n\t\t\t\t\ta)\tIf the manual cycle and lockout shaft can notbe turned more than approximately 1/4 turn, the second lock dog is serviceable. \n\t\t\t\t\tb)\tIf the manual cycle and lockout shaft can be \t\t\t\t\t\tturned more than approximately 1/4 turn, the second lock dog is unserviceable. Lock the \t\t\t\tthrust reverser until the No. 3 gearbox is replaced. \n\n\t\t\t\t\tNOTE:\tThe two lock dogs are found 1/2 turn apart when you use the manual cycle and lockout shaft. If necessary, do the check again to make sure that the lock dogs are serviceable. \n\n\t\t\t\t8)\tDo the procedure given above for the No. 2 gearbox lock. \n\t\t(5)\tInstall the lock bars in the manual cycle and lockout shafts at the No. 2 and No. 3 gearboxes. \n\t\t(6)\tApply the air motor manual brake: \n\t\t\t(a)\tTurn the air motor brake release handle clockwise and then release. \n\t\t\t(b)\tClose the air motor access and pressure relief panel. \n\t\t(7)\tMake sure the No. 2 and No. 3 gearbox locks are released. \n\t\t\t(a)\tMake sure the lock indicator rods are extended at the No. 2 \t\t\t\tand No. 3 gearboxes. \n\t\t(8)IF YOU USE THE LOAD TOOLS; \n\t\t\tTry to move the translating cowl in the extend direction as follows: \n\t\t\t(a)\tRemove the lock bars from the No. 2 and No. 3 gearboxes. \n\t\t\t(b)\tInstall the load tools through the cutouts and into the No. 2 \t\t\t\tand No. 3 gearboxes. \n\t\t\t(c)\tAttach the torque wrenches to the load tools. \n\t\t\t(d)\tTry to move the translating cowl in the extend direction. \n\t\t(9)\tIF YOU DO NOT USE THE LOAD TOOLS; \n\t\t\tTry to move the translating cowl in the extend direction as follows: \n\t\t\t(a)\tRemove the lock bars from the No. 2 and No. 3 gearboxes. \n\t\t\t(b)\tPut the 0.25 inch (6.4 mm) square drive extensions into the \t\t\t\tmanual cycle and lockout shaft at the No. 2 and No. 3 gearboxes. \n\t\t\t\t1)\tAttach the standard drive tools. \n\t\t\t(c)\tTry to move the translating cowl in the extend direction. \n\t\t(10)\tIf the translating cowl moves, do the full test again. \n\t\t\t(a)\tIf the translating sleeve moves again, lock the thrust reverser \t\t\t\tuntil you can replace the two locking gearboxes and the air motor and shutoff valve. \n\t\t(11)\tRemove the access stools and protection pads. \n\t\t(12)\tRemove the INA access platform from the exhaust mixer duct. \n\t\t(13)\tDo the activation procedure of the thrust reverser system. \n\t\t(14)\tDo the functional test of the thrust reverser system.

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 767 series airplanes was published in the Federal Register on August 6, 1993 (58 FR 42032). That action proposed to supersede AD 91-22-02, Amendment 39-8062 (56 FR 51638, October 15, 1991), to require inspections, adjustments, and functional checks of the thrust reverser system on Model 767 series airplanes equipped with Rolls-Royce RB211-524 or General Electric CF6-80C2 series engines. That action also proposed to require installation of a terminating modification and repetitive operational checks of the gearbox locks and the air motor brake following accomplishment of that modification on Model 767 series airplanes equipped with Rolls-Royce RB211-524 series engines. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due considerationhas been given to the comments received. \n\n\tOne commenter supports the proposed rule. \n\n\tThe Air Transport Association (ATA) of America, on behalf of one of its members, requests that two immediately adopted rules be created from this proposed rule: one for airplanes equipped with Rolls-Royce RB211-524 series engines, and the other for the airplanes equipped with General Electric CF6-80C2 series engines. If either of the two rules should be revised in the future, the superseded rule would only apply to the operators actually affected, and operators having airplanes with the other engine type would not be required to change their AD compliance records. \n\n\tThe FAA concurs that two separate AD's should be created from the proposal. Therefore, this final rule has been revised to require those actions specified in the proposal for Model 767 series airplanes equipped with Rolls-Royce RB211-524 series engines only. Paragraph (a) of this final rule has been revised to specify that accomplishment of the actions required by that paragraph terminates the actions required by paragraph (a) of AD 91-22-02. Subsequently, the FAA may consider superseding AD 91-22-02 to remove the requirements for Model 767 series airplanes equipped with Rolls-Royce RB211-524 series engines from that AD, to specify that those requirements are contained in this AD, and to require accomplishment of a terminating modification for Model 767 series airplanes equipped with General Electric CF6-80C2 series engines (once that modification becomes available). \n\n\tThe economic impact information, below, has also been revised to specify the costs associated with accomplishment of the actions required by this AD for those airplanes equipped with Rolls-Royce RB211-524 series engines only. \n\n\tBoeing requests that specific references to page numbers and revision dates of the Boeing 767 Airplane Maintenance Manual (AMM) be eliminated from the AD. Boeing recommends that the proposed AD specify only the ATA Chapter-Section-Subject, pageblock, and task title. Boeing explains that the AMM's are customized for each operator to reflect all of the equipment in that operator's fleet. Therefore, the number of pages for any given procedure is variable, depending on the number of different equipment configurations documented in an operator's AMM. \n\n\tBoeing also indicates that AMM procedures are revised periodically for non-technical reasons. Boeing adds that changes to the structure of the procedures are necessary to accommodate an upgrade of the publishing system that is currently under way, which, in addition to repagination, will necessitate the issuance of revised AMM pages. \n\n\tBoeing states that the effect of specifying AMM page numbers and revision dates in the AD is that operators may be unable to use the procedure contained in the AMM to perform certain tests required by the AD. Each operator would be required to maintain an obsolete version of the procedure, or to request FAA approval of an alternative method of compliance with the AD that would allow the use of the current version of the AMM. \n\n\tThe FAA concurs partially. In light of the information submitted by the commenter, the FAA agrees that specific AMM page numbers and dates should not be specified in the final rule. However, the FAA does not agree with the commenter's recommendation that the final rule specify the ATA Chapter-Section-Subject, pageblock, and task title. The FAA's objective in proposing periodic operational checks of the gearbox locks and the air motor brake is to ensure the integrity of the locking function. Since the issuance of the proposal and receipt of Boeing's comments to the proposal, Boeing has submitted to the FAA separate procedures for accomplishment of the operational check of the integrity of the gearbox locks and the air motor brake. For clarification purposes, the requirements of paragraph (d) of the proposal have been separated into two paragraphs ((c) and (d)) of the final rule. The AMM references specified in paragraph (c) of the proposal have been removed from the final rule. Paragraph (d) of the final rule specifies that the operational checks are required to be accomplished in accordance with the procedures that appear in Appendix 1 (including Figure 1) of this AD. \n\n\tSince the issuance of the proposal, the FAA has reviewed and approved Boeing Service Bulletin 767-78-0059, Revision 3, dated January 20, 1994, which adds a note in several locations to specify that whenever a changed or disconnected connector is connected, an inspection of the disconnected electrical connectors to detect bent or pushed-back pins should be performed. This inspection is necessary simply to verify the correct installation of the connectors; the FAA does not consider that this inspection will impose an additional burden on any operator. Additionally, the revised service bulletin references the latest version of a particular wire kit to show changes inwiring information. Paragraph (c) of the final rule has been revised to reflect the latest revision of the service bulletin as an additional source of service information. \n\n\tIt should be noted that Revisions 2 and 3 of Boeing Service Bulletin 767-78-0059 reference Rolls-Royce Service Bulletins RB.211-71-9608, RB.211-71-9600, and RB.211-71-9601, and Eldec Service Bulletin 8-651-32-01 as additional sources of service information for accomplishment of the locking gearbox installation. However, the Boeing service bulletins do not specify the appropriate revision levels for those Rolls-Royce and Eldec service bulletins. Therefore, the FAA has added "NOTE 1" to paragraph (c) of this AD to specify that the intent of that paragraph is that the appropriate revision levels for the Rolls-Royce and Eldec service bulletins to be used in conjunction with Boeing Service Bulletin 767-78-0059 are as follows: Rolls-Royce Service Bulletin RB.211-71-9608, Revision 1, dated October 2, 1992; Rolls-Royce Service Bulletin RB.211-71- 9600, Revision 4, dated February 11, 1994; Rolls-Royce Service Bulletin RB.211-71-9601, Revision 1, dated October 2, 1992; and Eldec Service Bulletin 8-651-32-01, dated January 31, 1992. \n\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\n\tCurrently, there are no Model 767 series airplanes equipped with Rolls-Royce RB211-524 series engines on the U.S. Register. However, should an affected airplane be imported and placed on the U.S. Register in the future, it will require approximately 22 work hours to accomplish the inspections, adjustments, and functional checks, 754 work hours to accomplish the modification, and 1 work hour to accomplish the operational checks of the modification, at an average labor rate of $55 per work hour. Required parts will be supplied by the manufacturer at no cost to operators. Based on these figures, the total cost impact for the required actions will be $42,735 per airplane. \n\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\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\n List 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 delegated to 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\n\t1.\tThe authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. § 39.13 - (Amended) \n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: