AD 95-10-07

95-10-07 BELL HELICOPTER TEXTRON, INC. : Amendment 39-9224. Docket No. 95-SW-02-AD.

Applicability: Model 205A, 205A-1, and 204B helicopters, with a 42-degree tail rotor drive gearbox assembly (42-degree gearbox), part number (P/N) 204-040-003-023, or -037, 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 (e) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the 42-degree gearbox, loss of tail rotor control, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, after the effective date of this AD, verify that the tail rotor control system is rigged in accordance with the applicable maintenance manual.

(b) Before further flight, and thereafter at intervals not to exceed 400 torque events, disassemble the affected 42-degree gearbox and inspect for cracks at the roots of the gear teeth on the pinion, P/N 204-040-500-007 or -009, and gear, P/N 204-040-500-008 or -010, using a fluorescent penetrant inspection method in accordance with the applicable maintenance manual. Only post emulsified fluorescent penetrant inspection materials (Type I, Method B or D, Sensitivity Level 3 or greater) are approved for use. A torque event is defined as a takeoff or a lift (internal or external).

(c) If any crack is found at the roots of the gear teeth on the pinion or gear, replace the pinion or gear with an airworthy pinion or gear in accordance with the applicable maintenance manual.

(d) Create a component history card for the 42-degree gearbox. Record the number of torque events on a daily basis.

(e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used when approved by the Manager, Rotorcraft Certification Office, FAA, Rotorcraft Directorate. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager,Rotorcraft Certification Office.

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

(f) 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.

(g) This amendment becomes effective on May 26, 1995.