AD 97-23-07

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter Deutschland GmbH (Eurocopter) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, that establishes a new retirement life for the clutch and requires an entry into the Accessory Replacement Record indicating the new life limit. This amendment is prompted by a recalculation of life limitations by the part manufacturer, Warner Electric. The clutch manufacturer used the airframe load spectrum to establish the new life limit of 3,600 hours time-in-service (TIS). The actions specified by this AD are intended to prevent failure of the clutch, loss of power to the main rotor and a subsequent forced landing of the helicopter.

Final rule

97-23-07 EUROCOPTER DEUTSCHLAND GmbH: Amendment 39-10195. Docket No. 96-SW-23-AD.

Applicability: Model MBB-BK 117 A-1, A-3, A-4, B-1, and B-2 helicopters, serial numbers (S/N) 7001 through 7250, and Model MBB-BK 117 C-1 helicopters, S/N 7500 through 7520, with clutch, part number (P/N) 4639302044 or P/N CL42067-1, installed, certificated in any category.

NOTE 1: This AD applies to each helicopter 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 helicopters 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 (d) to request approval from the 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 describedin 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 helicopter from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the clutch, loss of power to the main rotor and a subsequent forced landing of the helicopter, accomplish the following:

(a) Within 30 hours time-in-service (TIS) after the effective date of this AD, make an entry into the Accessory Replacement Record to reflect a new life limit of 3,600 hours TIS for the clutch, P/N 4639302044 or P/N CL42067-1.

(b) Remove the clutch, P/N 4639302044 or P/N CL42067-1, from service on or before reaching 3,600 hours TIS. This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a new retirement life for the clutch, P/N 4639302044 or P/N CL42067-1, of 3,600 hours TIS.

(c) Replacement of the clutch, P/N 4639302044 or P/N CL42067-1, with a clutch, P/N 4639202011, constitutes a terminating action for the requirements of this AD.

(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, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(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 helicopter to a location where the requirements of this AD can beaccomplished.

NOTE 3: The subject of this AD is addressed in Luftfahrt-Bundesamt (Germany) AD 95-242, dated June 13, 1995.

(f) This amendment becomes effective on December 10, 1997.

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 Eurocopter Deutschland GmbH (Eurocopter) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters was published in the Federal Register on February 4, 1997 (62 FR 5186). That action proposed to establish a new retirement life for the clutch and to require an entry into the Accessory Replacement Record indicating the new life limit.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comment received.

The one commenter asked for a delay in the issuance of this AD until Warner Electric established a new retirement life on the affected clutch. The commenter indicated that an extended retirement life would be prepared by the clutch manufacturer by the end of May 1997. To date, the FAA has received no further information about an extension to the retirement life of the clutch.

After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for some non-substantive word changes, insertion of Note 3 referencing the Luftfahrt-Bundesamt (LBA) AD, and correction of the part number in paragraph (b). The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of this AD.

The FAA estimates that 130 helicopters of U.S. registry will be affected by this AD, that it will take approximately 12 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $6,000 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $873,600.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.

For 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 fromthe Rules Docket.

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, 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 USC 106(g), 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: