AD 97-23-07 Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB- BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters

Models named: MBB-BK 117 A-1, A-3, A-4, B-1, B-2, MBB- BK 117 C-1. Read the applicability below — it usually turns on serial or part numbers too.

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 [[Page 59781]] 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 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 helicopter from the applicability of this AD.

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 be accomplished. (f) This amendment becomes effective on December 10, 1997. Note 3: The subject of this AD is addressed in Luftfahrt- Bundesamt (Germany) AD 95-242, dated June 13, 1995. Issued in Fort Worth, Texas, on October 30, 1997. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 97-29238 Filed 11-4-97; 8:45 am] BILLING CODE 4910-13-U