AD 2001-16-03

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 767-200, -300, -300F, and -400ER series airplanes equipped with General Electric Model CF6-80C2 series engines. This action requires various repetitive inspections and tests of certain fail-safe features of the thrust reverser control system; and corrective actions, if necessary. This action is necessary to ensure that the fail-safe features of the thrust reverser are fully functional and to protect against an in-flight thrust reverser deployment, which could result in loss of controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule; request for comments.

2001-16-03 Boeing: Amendment 39-12371. Docket 2001-NM-137-AD. \n\n\tApplicability: Model 767-200, -300, -300F, and -400ER series airplanes, equipped with General Electric Model CF6-80C2 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 (e) 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 ensure that the fail-safe features of the thrust reverser are fully functional and to protect against an in-flight thrust reverser deployment, which could result in loss of controllability of the airplane, accomplish the following: \n\n\tNote 2: Where there are differences between this AD and the referenced service bulletins or the 767 Master Minimum Equipment List (MMEL), the AD prevails. \n\nRepetitive Inspections and Tests of Thrust Reverser Control System \n\n\t(a) Within 1,000 flight hours after the effective date of this AD, do a general visual inspection to detect discrepancies (i.e., wear, tears, cracks, missing segments, and improper folds, as applicable) and assess damage of the certain fail-safe features of the thrust reverser control system, and test for electrical continuity and resistance of those fail-safe features; per Section 3., "Accomplishment Instructions," of Boeing Alert Service Bulletin 767-78A0090, Revision 1, dated July 5, 2001 (for Model 767- 200, -300, and -300F series airplanes), or Boeing Alert Service Bulletin 767-78A0091, Revision 1, dated July 5, 2001 (for Model 767-400ER series airplanes); as applicable. Repeat the inspection and tests thereafter every 1,000 flight hours. \n\n\tNote 3: For the purposes of this AD, a general visual inspection is defined as "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked." \n\nCorrective Actions, If Necessary \n\n\t(b) Except as provided by paragraph (c) of this AD, do the applicable corrective actions specified in paragraph (b)(1), (b)(2), (b)(3), and (b)(4) of this AD per Boeing AlertService Bulletin 767- 78A0090, Revision 1, dated July 5, 2001 (for Model 767-200, -300, and -300F series airplanes), or Boeing Alert Service Bulletin 767- 78A0091, Revision 1, dated July 5, 2001 (for Model 767-400ER series airplanes); as applicable; at the time indicated in those paragraphs.\n \n\t\t(1) If any discrepancy is detected as indicated in Figure 1 of the applicable service bulletin, replace the bullnose seal with a new bullnose seal, per Figure 1 of the applicable service bulletin, at the applicable time indicated in paragraph (b)(1)(i) or (b)(1)(ii) of this AD. \n\n\t\t\t(i) For assessed cumulative damage between one and ten inches: Replace within 650 flight hours after the inspection.\n \n\t\t\t(ii) For assessed cumulative damage ten inches or more: Replace before further flight. \n\n\t\t(2) If the electrical continuity on the position switch module of the center drive unit (CDU) of the thrust reverser is found to be outside the limits (greater than 0.50 ohms) during any applicabletest required by paragraph (a) of this AD, before further flight, do the corrective actions (i.e., replace discrepant position switch module with a new module, or replace the CDU with a new CDU), per Part 2 of Section 3., "Accomplishment Instructions," of the applicable service bulletin. \n\n\t\t(3) If the resistance between pins 1 and 2 of either connector in the thrust reverser actuation system (TRAS) lock for "hot short" protection is greater than 4.0 ohms, before further flight, do the corrective actions (i.e., additional testing, replacement of the relay, and troubleshoot the connecting wires; as applicable) per Part 3 of Section 3., "Accomplishment Instructions," of the applicable service bulletin.\n \n\t\t(4) If the resistance between pins 1 and 2 of the connector in the directional pilot valve (DPV) for "hot short" protection is greater than 4.0 ohms, before further flight, do the corrective actions (i.e., additional testing, replacement of the microswitch pack, and troubleshoot the connecting wires; as applicable) per Part 4 of Section 3., "Accomplishment Instructions," of the applicable service bulletin. \n\nException to Corrective Action(s) \n\n\t(c) For those conditions identified in paragraph (b)(1) of this AD: The thrust reverser may be deactivated per the Master Minimum Equipment List (MMEL) for up to 10 days provided that, before further flight, the deactivation is done per Section 2-78-31-1 of Boeing Document D630T002, "Boeing 767 Dispatch Deviation Guide," Revision 20, dated August 18, 2000. Within 10 days following accomplishment of the deactivation, do the applicable corrective action(s) specified in paragraph (b)(1), (b)(2), or (b)(4) of this AD. Before further flight following accomplishment of the applicable corrective action(s), reactivate the thrust reverser. No more than one thrust reverser on any airplane may be deactivated under the provisions of this paragraph. \n\nEngine Replacement \n\n\t(d) Prior to installation of a General Electric ModelCF6-80C2 engine on any airplane, do the actions specified in paragraphs (d)(1) and (d)(2) of this AD, per Boeing Alert Service Bulletin 767- 78A0081, Revision 2, dated April 19, 2001 (for Model 767-200, -300, and -300F series airplanes), or Boeing Alert Service Bulletin 767- 78A0088, dated April 19, 2001 (for Model 767-400ER series airplanes), as applicable. \n\n\t\t(1) Do a functional test on both thrust reversers for the electro-mechanical brakes (i.e., TRAS locks) and CDU cone brakes of both engines to verify proper holding torque per the Accomplishment Instructions of the applicable service bulletin. If any improper holding torque is detected, before further flight, accomplish corrective actions (e.g., ensure proper torque, replacement or installation of components, and additional inspections), as applicable, per the Accomplishment Instructions of the applicable service bulletin. \n\n\t\t(2) Do a test for electrical continuity of the position switch module of the CDU of the thrust reverser, per Part 2 of Section 3., "Accomplishment Instructions," of the applicable service bulletin, and before further flight, do corrective actions, if necessary, as specified in paragraph (b)(2) of this AD. \n\nAlternative Methods of Compliance \n\n\t(e) 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. 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 4: 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 Permits \n\n\t(f) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a locationwhere the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(g) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 767- 78A0090, Revision 1, dated July 5, 2001; Boeing Alert Service Bulletin 767-78A0091, Revision 1, dated July 5, 2001; Boeing Alert Service Bulletin 767-78A0081, Revision 2, dated April 19, 2001; and Boeing Alert Service Bulletin 767-78A0088, dated April 19, 2001; as applicable. This 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\nEffective Date \n\n\t(h) This amendment becomes effective on August 21, 2001.

The FAA has received numerous reports of failures of the flexshaft of the thrust reverser actuation system (TRAS) lock (also known as electro-mechanical brake) between the upper actuator and the TRAS lock on Boeing Model 767-200, -300, -300F, and - 400ER series airplanes equipped with General Electric Model CF6-80C2 series engines. These failures were detected during operational checks required by paragraph (f) of AD 2000-09-04, amendment 39-11712 (65 FR 25833, May 4, 2000) (described further below). The TRAS lock provides a fail-safe level of protection against in-flight deployment of the thrust reverser by retaining the thrust reverser drive shaft. Investigation revealed that when the flexshaft fails, the TRAS lock cannot retain the thrust reverser drive shaft and is effectively removed from the thrust reverser system. There is no airplane system to detect this failure and the cause is unknown at this time. This condition, if not corrected, could result in the loss of the fail-safe level of protection against an in-flight thrust reverser deployment. Such a loss increases the risk of an in-flight thrust reverser deployment, which could result in loss of controllability of the airplane. \n\nOther Relevant Rulemaking \n\n\tThe FAA has previously issued AD 2000-09-04, which requires tests, inspections, and adjustments of the thrust reverser on Boeing Model 767 series airplanes equipped with General Electric Model CF6-80C2 series engines. That AD also requires installation of a terminating modification, and repetitive follow-on actions. The tests and inspections of the TRAS lock (electro-mechanical brake) required by paragraph (f) of that AD were intended to detect and correct latent failures of the TRAS lock. Because of the numerous reports above, we find that further rulemaking action is necessary to address the identified unsafe condition. However, this AD will not affect the current requirements of AD 2000-09-04. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 767-78A0090, Revision 1, dated July 5, 2001 (for Model 767-200, -300, and -300F series airplanes), and Boeing Alert Service Bulletin 767- 78A0091, Revision 1, dated July 5, 2001 (for Model 767-400ER series airplanes). The service bulletins describe the following procedures: \n\n\t1. Repetitive general visual inspections of the bullnose seal to detect discrepancies (i.e., wear, tears, cracks, missing segments, and improper folds, as applicable) and assess damage; and replacement of the bullnose seal with a new bullnose seal, if necessary. \n\n\t2. Repetitive tests of the electrical connector P3/P4 of the left and right position switch modules of the center drive unit (CDU) of the thrust reverser for electrical continuity (0.50 ohms or less) between pins 3 and 4 and between pins 5 and 6; and replacement of the left and right position switch modules with new modules, if necessary.\n \n\t3. Repetitive"hot short" protection tests to verify that the resistance between pins 1 and 2 of each connector of the TRAS lock on the left and right engines is 4.0 ohms or less; and corrective actions (i.e., additional testing, replacement of the relay, and troubleshoot the connecting wires; as applicable), if necessary. \n\n\t4. Repetitive "hot short" protection tests to verify that the resistance between pins 1 and 2 of connection P5 of the directional pilot valve (DPV) is 4.0 ohms or less, and corrective actions, if necessary. \n\n\tIn addition, the FAA has reviewed and approved Boeing Alert Service Bulletin 767-78A0081, Revision 2, dated April 19, 2001 (for Model 767- 200, -300, and -300F series airplanes), and Boeing Alert Service Bulletin 767-78A0088, dated April 19, 2001 (for Model 767-400ER series airplanes). These service bulletins describe procedures for a functional test on both thrust reversers for the electro-mechanical brakes (i.e., TRAS locks) and CDU cone brakes of both engines to verify proper holding torque; and corrective actions, if necessary. The corrective actions involve ensuring proper torque, installing or replacing components with new components, and performing additional inspections; as applicable. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other Boeing Model 767-200, -300, -300F, and -400ER series airplanes equipped with General Electric Model CF6-80C2 series engines of the same type design, this AD is being issued to ensure that the fail-safe features of the thrust reverser are fully functional and to protect against an in-flight thrust reverser deployment, which could result in loss of controllability of the airplane. This AD requires accomplishment of the actions specified in the applicable service bulletins described previously, except as discussed below. \n\nDifferences Between the Service Bulletins and AD \n\n\tThe 767 Master Minimum Equipment List (MMEL) allows the thrust reverser under certain conditions, to be deactivated for up to 10 days; however, it does not describe procedures for accomplishment of such a task. The deactivation procedures are described in Section 2-78-31-1 of Boeing Document D630T002, "Boeing 767 Dispatch Deviation Guide," Revision 20, dated August 18, 2000. Therefore, the FAA finds that, in lieu of certain corrective actions described in Boeing Alert Service Bulletin 767-78A0090, Revision 1, dated July 5, 2001 (for Model 767- 200, -300, and -300F series airplanes), and Boeing Alert Service Bulletin 767-78A0091, Revision 1, dated July 5, 2001 (for Model 767- 400ER series airplanes), the thrust reverser may be deactivated per the MMEL for up to 10 days provided that the following actions are done:\n \n\t1. Before further flight, the deactivation is done per Section 2- 78-31-1 of Boeing Document D630T002, \n"Boeing 767 Dispatch Deviation Guide," Revision 20, dated August 18, 2000;\n \n\t2. Within 10 days followingaccomplishment of the deactivation, the applicable corrective action(s) specified in paragraph (b) of this AD are done; and \n\n\t3. Before further flight following accomplishment of the applicable corrective action(s), the thrust reverser is reactivated.\n \n\tWe find that accomplishment of the optional deactivation procedures above for up to 10 days is acceptable for affected airplanes to continue to operate without compromising safety. \n\n\tOperators should note that, although Boeing Alert Service Bulletin 767-78A0081, Revision 2, dated April 19, 2001 (for Model 767-200, -300, and -300F series airplanes), and Boeing Alert Service Bulletin 767- 78A0088, dated April 19, 2001 (for Model 767-400ER series airplanes), recommend accomplishing the functional test on both thrust reversers for the electro-mechanical brakes (i.e., TRAS lock) and CDU cone brakes of both engines within 650 flight hours (after the receipt of the service bulletin), the FAA has determined that an interval of 650 flight hours would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this proposed AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, as well as the numerous reports of failures of the flexshaft of the TRAS lock (described above). In light of all of these factors, we find that accomplishing the functional test prior to installation of a General Electric Model CF6-80C2 engine to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. \n\nInterim Action \n\n\tThis is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. \n\nDetermination of Rule's Effective Date \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.\n \n\tSubmit comments using the following format: \n\nOrganize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues. \nFor each issue, state what specific change to the AD is being requested. \nInclude justification (e.g., reasons or data) for each request. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.\n \n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2001-NM-137-AD." The postcard will be date stamped and returned to the commenter. \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\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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. \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. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: