AD 86-17-09

86-17-09 BELL HELICOPTER TEXTRON, INC.: Letter issued August 21, 1986. Applies to all Bell Helicopter Model 212 helicopters, S/N 30501 through 30999, 31101 through 31273, and 31275; 32101 through 32142 and 32201 through 32262 that have T/R hub and blade assembly, P/N 212-011-701-001 installed, certified in any category.

Compliance required as indicated unless already accomplished.

To prevent failure of the tail rotor control, accomplish the following:

(a) Within 25 hours' time in service after receipt of this AD, visually inspect the T/R hub assembly P/N 212-011-701-3, in accordance with Part 1 of Bell Helicopter Textron, Inc. (BHTI), Alert Service Bulletin (ASB) 212-86-39, Revision "A," dated July 23, 1986.

(1) If the (P/N) 212-011-716-1 T/R trunnion housing is cracked or there is axial play in the T/R trunnion, or if there are excess balance washers, comply with Part II of the Alert Service Bulletin before further flight.

(2) Repeat this inspection every 25 hours' time in service until paragraph (b) of this AD is accomplished.

(b) Remove the 212-011-701-1 T/R hub and blade assembly and inspect the trunnion bearing housing, P/N 212-011-716-1, as detailed in Part II of BHTI ASB 212-86-39, Revision "A", dated July 23, 1986, within 150 hours' time in service or within 60 days after the issue date of this AD, whichever occurs first. Replace any housing having an end web thickness of .059 inch or less with a serviceable part.

An alternate method of compliance or adjustment of the compliance time, which provides an equivalent level of safety, may be approved by the Manager, Helicopter Certification Branch, Aircraft Certification Division, FAA, Southwest Region.

This airworthiness directive becomes effective upon receipt.