AD 95-10-11

This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-80C2 series turbofan engines. This action requires an initial and repetitive brake holding torque check of the fan reverser center drive unit (CDU), visual inspection of the translating cowl inner bondment seal, and functional check of the translating cowl auto re-stow system. This action also requires removal and replacement of certain CDU's as a terminating action to the repetitive check and inspection program. This amendment is prompted by a report of a CDU not able to hold the fan reverser translating cowl at the required position when manually driven to its stow position during routine maintenance. The actions specified in this AD are intended to prevent the loss of the CDU's brake holding feature, which could result in possible movement of the fan reverser translating cowl towards the deploy position in flight.

Final rule; request for comments.

95-10-11 General Electric Company: Amendment 39-9228. Docket 95-ANE-17.

Applicability: General Electric Company (GE) CF6-80C2 series turbofan engines installed on, but not limited to, Airbus A300 and A310 series, Boeing 747 and 767 series, and McDonnell Douglas MD-11 series aircraft.

NOTE: This airworthiness directive (AD) applies to each engine 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 engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (e) to request approval from the Federal Aviation Administration (FAA). This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any engine from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent a loss of the center drive units (CDU) brake holding feature, which could result in possible movement of the fan reverser translating cowl towards the deploy position in flight, accomplish the following:

(a) For fan reversers that have a CDU identified in paragraph 1.A.(1) of Martin Marietta (MM) CF6-80C2 Service Bulletin (SB) No. 78-1002, Revision 1, dated March 23, 1995, installed, perform the following:

(1) If the requirements of MM CF6-80C2 SB No. 78-1002, dated February 27, 1995, or MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, have not been previously accomplished, perform a brake holding torque check of the fan reverser CDU, a visual inspection of the translating cowl inner bondment seal, and a functional check of the translating cowl auto re-stow system in accordance with paragraphs 2.B, 2.C, and 2.D of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to accumulating 250 cycles in service (CIS) or 30 days, after the effective date of this AD, whichever occurs earlier.

(2) If the requirements of MM CF6-80C2 SB No. 78-1002, dated February 27, 1995, or MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, have been previously accomplished, accomplish the following:

(i) Perform a brake holding torque check of the fan reverser CDU in accordance with paragraph 2.B of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to accumulating 250 CIS since the last brake holding torque check.

(ii) Perform a visual inspection of the translating cowl inner bondment seal, and a functional check of the translating cowl auto re-stow system in accordance with paragraphs 2.C and 2.D of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to accumulating 1,000 hours since the last visual inspection of the translating cowl inner bondment seal and functional check of the translating cowl auto re-stow system.

(b) Thereafter, for fan reversers that have accomplished the inspection and check requirements in accordance with paragraph (a) of this AD, accomplish the following:

(1) Perform a brake holding torque check of the fan reverser CDU in accordance with paragraph 2.B of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to accumulating 250 CIS since the last brake holding torque check.

(2) Perform a visual inspection of the translating cowl inner bondment seal, and a functional check of the translating cowl auto re-stow system in accordance with paragraphs 2.C and 2.D of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to accumulating 1,000 hours since the last visual inspectionof the translating cowl inner bondment seal and functional check of the translating cowl auto re-stow system.

(c) Remove from service the CDU's identified in paragraph 1.A.(1) of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, in accordance with paragraph 2.F of MM CF6-80C2 SB No. 78-1002, Revision 1, dated March 23, 1995, prior to December 31, 1995, and replace with a serviceable part. Removal and replacement of the CDU in accordance with this paragraph constitutes terminating action to the initial and repetitive inspection and check requirements of paragraph (a) and (b) of this AD.

(d) For the purpose of this AD, a serviceable part is defined as a CDU that has accomplished any revision level of MM CF6-80C2 SB No. 78-1014; or a CDU whose shaft has received the hardness inspection in accordance with any revision level of GE CF6-80C2 SB No. 78-131, and that has not had a brake shaft replacement subsequent to the hardness inspection.

(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, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternate methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.

(f) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished.

(g) The actions required by this AD shall be done in accordance with the following service bulletin:

Document No.:
Pages:
Revision:
Date:
Martin Marietta CF6-80C2
2, 11, 12, 14-18, 20
Original
February 27, 1995
SB No. 78-1002
1, 3-10, 13, 19
1
March 23, 1995
Total pages: 20

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 Martin Marietta Services, Inc., Attn: Karen Lyons, 10525 Chester Road, Cincinnati, OH 45215. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment becomes effective on May 31, 1995.

The Federal Aviation Administration (FAA) received a report of a center drive unit (CDU) not able to hold the fan reverser translating cowl at the required position when manually driven to its stow position during routine maintenance. Investigation revealed that the CDU brake shaft had worn to the extent that the braking feature was inoperative. This feature, in conjunction with two additional features (auto re-stow and stow retention), prevents the uncommanded movement of the translating cowl towards the deploy position. Further investigation revealed that the wear was due to the low material hardness of the brake shaft. This low material hardness is the result of a heat treat step that was inadvertently omitted from the manufacturing cycle of the brake shaft. This condition, if not corrected, could result in loss of the CDU's brake holding feature, which could result in possible movement of the fan reverser translating cowl towards the deploy positionin flight.

The FAA has reviewed and approved the technical contents of Martin Marietta CF6-80C2 Service Bulletin (SB) No. 78-1002, Revision 1, dated March 23, 1995, that describes procedures for the brake holding torque check of the fan reverser CDU, visual inspection of the translating cowl inner bondment seal, functional check of the translating cowl auto re-stow system, and the removal and replacement of the CDU.

Since an unsafe condition has been identified that is likely to exist or develop on other General Electric Company (GE) CF6-80C2 series turbofan engines of the same type design, this AD is being issued to prevent the loss of the CDU's brake holding feature, which could result in possible movement of the fan reverser translating cowl towards the deploy position in flight. This AD requires an initial and repetitive brake holding torque check of the fan reverser CDU, visual inspection of the translating cowl inner bondment seal, and functional check of the translating cowl auto re-stow system. This AD also requires removal and replacement of certain CDU's as a terminating action to the repetitive check and inspection program. The actions are required to be accomplished in accordance with the service bulletin described previously.

Since 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.

Comments Invited

Although 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 should identify the Rules Docket number and be submitted in triplicate to theaddress 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.

Comments 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.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 95-ANE-17." The postcard will be date stamped and returned to the commenter.

The 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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and 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." List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. 39.13 - [AMENDED]

2. Section 39.13 is amended by adding the following new airworthiness directive: