82-15-01 R1: Main Transmission

82-15-01 R1 HUGHES HELICOPTERS: Amendment 39-4414 as amended by Amendment 39-4463. Applies to Model 269A (all S/N's), TH-55A (all S/N's converted to civil use), 269A-1 (all S/N's), 269B (all S/N's), and 269C (S/N's 0001 through 1074) helicopters equipped with main transmission assemblies P/N 269A5175-7, -9, -11, -13, -15, and -17, except those transmissions with the letter "W" on the transmission nameplate below and adjacent to the transmission serial number. Applies to helicopters certificated in all categories. Compliance is required as indicated unless already accomplished. To prevent failure of the main transmission, accomplish the following: (a) Within 50 hours' additional time in service after the effective date of this AD, disassemble the transmission and inspect the ring gear/carrier interface and attachment bolts for possible fretting or cracking, and rework in accordance with Service Information Notice N-181, paragraphs a. through j., or later FAA approvedequivalent. All parts that cannot be reworked within the criteria of Service Information Notice N-181 are considered unairworthy and must be replaced with like serviceable parts. NOTE: Those portions of Service Information Notice N-181 which address disposition of parts which exceed the prescribed inspection and rework criteria are not applicable. (b) Reassemble the transmission in accordance with Service Information Notice N- 181, paragraphs k. through o., or FAA approved equivalent. (c) Special flight permits may be issued in accordance with Sections 21.197 and 21.199 of the Federal Aviation Regulations to operate aircraft to a base for the accomplishment of inspections or modifications required by this AD. (d) Alternative inspections, modifications, or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Certification Field Office, FAA Northwest Mountain Region, 15000 Aviation Boulevard, Room 5W26, Hawthorne, California. Amendment 39-4414 became effective July 12, 1982. This Amendment 39-4463 becomes effective October 4, 1982.