AD 98-17-15 Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters

Models named: S-76A, B, C. Read the applicability below — it usually turns on serial or part numbers too.

Model S-76A, B, and C helicopters, serial numbers prior to 760488, with swashplate assembly, part numbers 76104-08000- 044, -045, -046, or 76104-08500-041 or -043, 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 (c) 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.

Required before further flight, unless accomplished previously. To prevent failure of the swashplate assembly, loss of control of the main rotor, and subsequent loss of control of the helicopter, accomplish the following: (a) Conduct a one-time visual inspection of the swashplate assembly uniball bearing retainer (retainer) to determine whether any retainer bolts are missing. Replace any missing retainer bolt with an airworthy AN3-5A bolt. (b) Conduct a one-time inspection of each swashplate assembly retainer bolt (12 installed) with a magnet to verify that a steel bolt is installed. The steel bolts will attract the magnet, the aluminum bolts will not. Replace any aluminum bolt, one at a time, with an airworthy AN3-5A bolt. Note 2: Sikorsky Aircraft Corporation Service Bulletin 76-65-47, dated July 31, 1998, pertains to the subject of this AD. (c) 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, Boston 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, Boston Aircraft Certification Office. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Boston Aircraft Certification Office. (d) Special flight permits will not be issued. (e) This amendment becomes effective on February 1, 1999, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-17-15, issued August 13, 1998, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on January 7, 1999. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-907 Filed 1-14-99; 8:45 am] BILLING CODE 4910-13-P