AD 92-06-17

Final Rule of a Priority Letter AD

92-06-17 ROBINSON HELICOPTER COMPANY (RHC): Amendment 39-8293. Docket No. 92-ASW-14. Final Rule of a Priority Letter AD.

Applicability: All Model R22 series helicopters, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of NAS1304-16 AF bolts, resulting in loss of helicopter control, accomplish the following:

(a) Within the next 10 hours' time in service or before March 30, 1992, whichever comes first, visually inspect the helicopters specified in (1), at the inspection areas or locations specified in (2), to determine the identification of the NAS1304-16 bolts.

(1) The helicopters affected are--

(i) R22 Serial Numbers (S/N) 1880 through 2060 and S/N 2073;

(ii) All R22 helicopters regardless of S/N overhauled or repaired at Robinson Helicopter Company between July 9, 1991, and March 1, 1992; and

(iii) All R22 helicopters regardless of S/N for which maintenance was performedafter July 9, 1991, in the inspection locations specified in paragraph (a)(2).

(2) The inspection locations are--

(i) The tail rotor blade control assembly at the aft end of the tail cone, including tail rotor controls connecting the rotor blade pitch link to the rotor pitch control cross head (slider) arms, and the rotor pitch link to the rotor blade attachment;

(ii) The lower aft corners of the cabin, both left-hand and right-hand sides, where the attachment joins the cabin to the welded frame assembly; and

(iii) The region above the swashplate attaching the counter weights (balance weights) to the swashplate assembly (also described as the main rotor balance weights attachment to the Chord Arm Yoke).

NOTE: Further details of the installations are contained in Robinson Model R22 Illustrated Parts Catalog (IPC).

(b) Before further flight, remove those NAS1304-16 bolts bearing the identification letters "AF" on the head of the bolt and replace with serviceable NAS1304-16 bolts with head marking other than "AF" or with NAS6604-16 bolts.

(c) After the effective date of this AD, NAS1304-16 bolts identified with the letters "AF" shall no longer be installed as a replacement part in any application on these helicopters.

(d) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office, 3229 E. Spring Street, Long Beach, California 90806-2425. The request shall be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.

(e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(f) Copies of the applicable service information may be obtained from Robinson Helicopter Company, 24747 Crenshaw Blvd, Torrance, CA 90505. This information may be examined at the FAA, Office of the Assistant Chief Counsel, Rules Docket, 4400 Blue Mound Road, Bldg. 3B, Room 158, Fort Worth, Texas.

(g) This amendment becomes effective July 24, 1992, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 92-06-17, issued March 17, 1992, which contained the requirements of this amendment.