AD 90-03-09

90-03-09 BELL HELICOPTER TEXTRON, INC.: Amendment 39-6465. Docket No. 89- ASW-69.

Applicability: All BHTI Model 205A and 205A-1 helicopters with retrofit kit, P/N 212- 704-129-101, installed (reference Bell Service Instructions 212-68, May 29, 1981); all Model 212 helicopters, S/N's 30501 through 30999, 31101 through 31273, 31275, 32101 through 32142, and 32201 through 32262 with T/R hub and blade assembly, P/N 212-011-701-001, installed; and all Model 412 helicopters, S/N's 33001 through 33118, 33120, and 33121; certificated in any category.

Compliance: Required as indicated, unless already accomplished.

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

(a) For the Model 412: (1) Within the next 20 hours' time in service after the effective date of this AD, and every 20 hours' time in service thereafter, until the requirements of paragraph (a)(2) have been accomplished, visually inspect the T/R trunnion bearing housing assembly, P/N 212- 011-716-1, for cracks in the end web. If cracks are present, remove and replace with a serviceable part before further flight.

(2) Within the next 150 hours' time in service or within 60 days after the effective date of this AD, whichever occurs first, remove the T/R hub and blade assembly, P/N 212-011-701-1, and measure the end web thickness of the trunnion bearing housing, P/N 212- 011-716-1. Replace any housing with an end web thickness of 0.059 inches or less with a serviceable part.

NOTE: Accomplishment of Bell Helicopter Alert Service Bulletin (ASB) 412-86-25, Revision "A", dated July 23, 1986, fulfills the requirements of paragraph (a).

(b) For the Model 205A, 205A-1, and 212: (1) Within the next 25 hours' time in service after the effective date of this AD, and every 25 hours' time in service thereafter, until the requirements of paragraph (b)(2) have been accomplished, visually inspect the T/R trunnion bearing housing assembly, P/N 212- 011-716-1, for cracks in the end web. If cracks are present, remove and replace with a serviceable part before further flight.

(2) Within the next 150 hours' time in service or within 60 days after the effective date of this AD, whichever occurs first, remove the T/R hub and blade assembly, P/N 212-011-701-1, and measure the end web thickness of the trunnion bearing housing, P/N 212- 011-716-1. Replace any housing with an end web thickness of 0.059 inches or less with a serviceable part.

NOTE: For Models 205A, 205A-1, and 212, accomplishment of Bell Helicopter Alert Service Bulletins (ASB) 205-86-24 Revision "A" dated July 23, 1986, and ASB 212-86-39 Revision A, dated July 23, 1986, fulfills the requirements of paragraph (b).

(c) An alternate method of compliance or adjustment of the compliance time, which provides an equivalent level of safety, may be used when approved by the Manager, Rotorcraft Certification Office, ASW-170, FAA, FortWorth, Texas.

(d) In accordance with FAR Sections 21.197 and 21.199, flight is permitted to a base where removal and replacement of the affected trunnion bearing housing required by this AD may be accomplished.

This amendment (39-6465, AD 90-03-09) becomes effective on February 13, 1990, as to all persons except those persons to whom it was made immediately effective by Priority Letter AD's 86-16-11, issued August 14, 1986, and 86-17-09 and 86-17-10, issued August 21, 1986, which contained this amendment.