# AD 77-23-08: Cracks in Main Rotor Blades - Type: Airworthiness directive - Status: Current - Products: Schweizer 269A, 269A-1 and 269B - Effective: December 27, 1977 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-3081 - Registered aircraft: 134 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BAB4B2639E02327786256A39004F6270.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/77-23-08 ## The airworthiness directive 77-23-08 HUGHES HELICOPTERS: Amendment 39-3081. Applies to Hughes Models 269A, 269A-1, 269A-2, and 269B helicopters equipped with main rotor blade P/N 269A1125, all blade Serial Numbers; P/N 269A1131, all blade Serial Numbers; P/N 269B1145, all blade Serial Numbers; P/N 269A1131-1, all blade Serial Numbers; P/N 269B1145-1, all blade Serial Numbers; and P/N 269B1145-25, all blade serial numbers. Compliance required as indicated. Small cracks have been discovered on several main rotor blades under the blade root fittings, radiating from the outboard bolt hole on the upper and lower side of the blade. To prevent main rotor blade failure due to extension of these cracks under the fittings, unless already accomplished, accomplish the following: (a) For main rotor blade P/N 269A1125, all Serial Numbers; P/N 269A1131, all Serial Numbers; and P/N 269B1145, Serial Nos. 0001 through 1313 - (1) Prior to the accumulation of 210 hours' time in service for main rotor bladeshaving less than 200 hours' time in service on January 16, 1967, and within the next 10 hours' time in service for main rotor blades having between 200 and 1000 hours' time in service on January 16, 1967, unless already accomplished within the last 390 hours' time in service, and thereafter at periods not to exceed 400 hours' time in service from the date of the last inspection, until a total of 1000 hours' time in service is reached, inspect in accordance with Hughes Service Information Notice No. N-9.2, dated October 3, 1977, or later FAA approved revision. (2) For main rotor blades accumulating a total of 1000 hours' time in service, subsequent to January 16, 1967, and for main rotor blades having 1000 or more hours' time in service on January 16, 1967, within the next 10 hours time in service, unless already accomplished within the last 90 hours' time in service, and thereafter at periods not to exceed 100 hours' time in service from the date of the last inspection until themain rotor blade is retired from service, inspect in accordance with Hughes Service Information Notice No. N-9.2, dated October 3, 1977, or later FAA approved revision. (b) For main rotor blade P/N 269A1131-1, all Serial Numbers; P/N 269B1145-1, all Serial Numbers; P/N 269B1145, Serial Nos. 1314 and subsequent; and P/N 269B1145-25, all Serial Numbers. Prior to the accumulation of 1025 hours' time in service for main rotor blades having less than 1000 hours' time in service on the effective date of this AD, and within the next 25 hours' time in service for main rotor blades having 1,000 or more hours' time in service on the effective date of this AD, unless already accomplished within the last 75 hours' time in service from the date of the last inspection until the main rotor blade is retired from service, inspect in accordance with Hughes Service Information Notice No. N-9.2, dated October 3, 1977, or later FAA approved revision. (c) Cracked blades must be removed before further flight, marked conspicuously to avoid inadvertent return to service, and replaced with new or serviceable used blades in accordance with (1), (2), or (3) below. Blades listed in (1), (2), and (3) are different types. Do not intermix types (1), or (2) or (3) blades. Main rotor blades, either those originally installed or replacement blades, must meet the requirements of this AD and must be retired from service before they exceed their maximum service life of 1366 hours' time in service. (1) Main rotor blade P/N 269B1145 and/or P/N 269B1145-1 and/or P/N 269B1145-25. (2) Main rotor blade P/N 269A1131 and/or P/N 269A1131-1. (3) Main rotor blade P/N 269A1125. This supersedes Amendment 39-642 (33 FR 12085), AD 68-17-07. This amendment becomes effective December 27, 1977. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 4H12](https://openairdocs.org/tcds/4H12): Schweizer RSG LLC; names 3 of 6 models: 269B, 269A-1, 269A ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 134 (134 by airframe model, 0 by engine model) - Makers: Hughes 133, Schweizer 1 Models with the most aircraft: - [Hughes 269A](https://openairdocs.org/model/hughes-269a): 97 aircraft (airframe model) - [Hughes 269B](https://openairdocs.org/model/hughes-269b): 31 aircraft (airframe model) - [Hughes 269A-1](https://openairdocs.org/model/hughes-269a-1): 5 aircraft (airframe model) - [Schweizer 269A](https://openairdocs.org/model/schweizer-269a): 1 aircraft (airframe model) All 4 models: https://openairdocs.org/ad/77-23-08/models.md Every aircraft: https://openairdocs.org/ad/77-23-08/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.