97-20-15: Outboard Tension-Torsion Bar Pin

97-20-15 HILLER AIRCRAFT CORPORATION: Amendment 39-10151. Docket No. 96-SW-32-AD. Supersedes AD 95-12-02, Amendment 39-9252. Applicability: Model UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E helicopters, 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 cracks in the head area of the outboard tension-torsion (T-T) bar pin, which could result in loss of in-plane stability of the main rotor blade and subsequent loss of control of the helicopter, accomplish the following: (a) Within 25 hours time-in-service (TIS) after the effective date of this AD, or at the next 100 hour inspection, whichever occurs first, and thereafter at intervals not to exceed 100 hours TIS, inspect the alignment of the outboard T-T bar pin, part number (P/N) 51452, and adjust the alignment, if necessary, in accordance with Hiller Aviation Service Letter (SL) 51-2, dated March 31, 1978. (b) Within 25 hours TIS after the effective date of this AD, or at the next 100 hour inspection, whichever occurs first, and thereafterat intervals not to exceed 100 hours TIS, inspect the head of the outboard T-T bar pin for cracks using a dye penetrant or magnetic particle inspection method. (c) If a crack is found as a result of the inspection required by paragraph (b) of this AD, report the results within 7 working days following the inspection to the Manager, Los Angeles Aircraft Certification Office, Attention Charles Matheis, ANM-120L, 3960 Paramount Blvd., Lakewood, California 90712-4137. Include the helicopter model number, serial number, and total TIS of the outboard T-T bar pin in the report. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056. (d) Within 25 hours TIS after the effective date of this AD, or at the next 100 hour inspection, whichever occurs first, install shims between the inboard end of the drag strut and the outboard T-T bar pin in accordance with the Accomplishment Instructions of Hiller Aviation Service Bulletin No. 51-9, dated April 8, 1983. (e) 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, Los Angeles Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office. NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft 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) The adjustment of the alignment of the T-T bar pin shall be done in accordance with Hiller Aviation SL 51-2, dated March 31, 1978, and the installation of the shims shall be done in accordance with Hiller Aviation Service Bulletin No. 51-9, dated April 8, 1983. These incorporations by reference were approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 on June 23, 1995. Copies may be obtained from Hiller Aircraft Corporation, 3200 Imjin Road, Marina, California 93933-5101, telephone (408) 384-4500, fax (408) 883-3648. Copies may be inspected at the FAA, Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (h) This amendment becomes effective on November 12, 1997.