# AD 79-12-10: Tail Rotor Blades - Type: Airworthiness directive - Status: Current - Products: Sikorsky S-61A, S-61D, S-61E, S-61L, S-61N, S-61NM, S-61R and S-61V - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-3496 - Registered aircraft: 54 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BAA0B9C97C8B738D86256A560052945D.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/79-12-10 ## The airworthiness directive 79-12-10 SIKORSKY: Amendment 39-3496. Applies to S-61 series helicopters certificated in all categories, including FAA certificated military counterparts, equipped with P/Ns S6115-30001 or S6117-30001 series tail rotor blades. To preclude the possibility of failure of the tail rotor blade, accomplish the following: 1. Inspect tail rotor blades, P/Ns S6115-30001 and S6117-30001, series for cracks in accordance with the following: a. Prior to further flight, unless already accomplished, dye penetrant inspect the inboard 32 inch section in accordance with Sikorsky Aircraft Service Bulletin 61B15-26. b. Thereafter, prior to the first flight of the day, conduct visual inspections of the blades in accordance with Sikorsky Service Bulletin 61B15-1E. c. Within the next six hours time in service, unless already accomplished, ultrasonically inspect the blades for spar and skin cracks in accordance with Sikorsky Service Bulletin 61B15-26. Thereafter for blades with over1200 hours time in service, inspect ultrasonically at intervals not to exceed six hours time in service in accordance with Sikorsky Service Bulletin 61B15-26. 2. Prior to further flight, unless already accomplished, perform a one-time dye penetrant or Zyglo inspection of the tail rotor gearbox mounting feet for cracks in accordance with Sikorsky Service Bulletin 61B15-26. 3. If a crack is found during the inspection of paragraph 1 or 2 above, replace the cracked blade or gearbox with a new or serviceable component, prior to further flight. A serviceable blade or gearbox is one that has been inspected in accordance with the subject service bulletins and found to be free of cracks. 4. Report in writing any cracks found during the inspections of paragraph 1 or 2 above to: Chief, Engineering and Manufacturing Branch, FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. Each report must include the length and location of the cracks and total time in service of the blade or gearbox. Reporting approved by the Office of Management and Budget under OMB No. 04-R0174. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Sikorsky Aircraft, Stratford, Connecticut 06602. These documents may also be examined at FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its Headquarters in Washington, D.C., and at the FAA, New England Headquarters, Burlington, Massachusetts. This amendment becomes effective upon publication in the Federal Register. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 1H15](https://openairdocs.org/tcds/1H15): Sikorsky Aircraft; names 4 of 4 models: S-61R, S-61N, S-61L, S-61NM - [TCDS H2EA](https://openairdocs.org/tcds/H2EA): Sikorsky Aircraft Corporation; names 4 of 4 models: S-61A, S-61D, S-61V, S-61E ## 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: 54 (54 by airframe model, 0 by engine model) - Makers: Sikorsky 53, Carson Helicopters / Sikorsky 1 Models with the most aircraft: - [Sikorsky S-61N](https://openairdocs.org/model/sikorsky-s-61n): 45 aircraft (airframe model) - [Sikorsky S-61A](https://openairdocs.org/model/sikorsky-s-61a): 5 aircraft (airframe model) - [Sikorsky S-61L](https://openairdocs.org/model/sikorsky-s-61l): 1 aircraft (airframe model) - [Sikorsky S-61NM](https://openairdocs.org/model/sikorsky-s-61nm): 1 aircraft (airframe model) - [Sikorsky S-61R](https://openairdocs.org/model/sikorsky-s-61r): 1 aircraft (airframe model) - [Carson Helicopters / Sikorsky S61A](https://openairdocs.org/model/carson-helicopters-sikorsky-s61a): 1 aircraft (airframe model) All 6 models: https://openairdocs.org/ad/79-12-10/models.md Every aircraft: https://openairdocs.org/ad/79-12-10/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.