AD 93-17-12

93-17-12 BELL HELICOPTER TEXTRON, INC. (BHTI): Amendment 39-8683. Docket No. 92-ASW-49. Supersedes AD 92-11-07, Amendment 39-8257.

Applicability: Model 204B, 205A, 205A-1, 205B, 212, and 412 helicopters, with main rotor transmission lower planetary spider (spider), part number (P/N) 204-040-785-003, installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue failure of the spider, which could result in failure of the main transmission and subsequent loss of control of the helicopter, accomplish the following:

(a) Within the next 600 hours' time-in-service (TIS) after the effective date of this AD, unless previously accomplished within the last 2,500 hours' TIS, and thereafter at intervals not to exceed 3,100 hours' TIS from the last magnetic particle inspection (MPI), remove the spider and perform an MPI for cracks in accordance with the pertinent BHTI maintenance, repair, and overhaul manuals.

(b) Replace any cracked spider with an airworthy part prior to further flight.

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

(d) 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.

(e) This amendment becomes effective on July 29, 1994.