# AD 74-25-05: Main Rotor Blades

- Type: Airworthiness directive
- Status: Current
- Products: Sikorsky S-61L, S-61N, S-61NM and S-61R
- Effective: November 6, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-2030
- Registered aircraft: 48 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F0FB80A990F20BC686256A560045A2AF.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-25-05

## The airworthiness directive

74-25-05 SIKORSKY: Amendment 39-2030. Applies to S-61L, S-61N, S-61NM and S- 61R helicopters certificated in all categories including Military Type CH-3C helicopters equipped with S6115-20501 series, S6115-20601 series, S6117-20101 series, and S6188-15001 series main rotor blades except for blades with serial numbers subsequent to 61M-6350-6105 and blades which have had all main rotor blade pockets replaced by Sikorsky Aircraft after October 30, 1972.

Compliance required within 5 hours time in service after the effective date of this AD.

The maximum never exceed speed is hereby reduced to 110 knots. Install placards as close as practicable to the airspeed indicators reading as follows: "Never exceed speed 110 knots."

This supersedes telegram dated October 8, 1974 and supersedes the maximum never exceed speed established by Airworthiness Directive 74-20-7, Amendment 39-1989.

This amendment becomes effective upon publication in the FEDERAL REGISTER for all persons except those to whom it was made effective immediately by telegram dated November 6, 1974.

## Affected data sheets (1) (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

## 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: 48 (48 by airframe model, 0 by engine model)
- Makers: Sikorsky 48

Models with the most aircraft:

- [Sikorsky S-61N](https://openairdocs.org/model/sikorsky-s-61n): 45 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)

All 4 models: https://openairdocs.org/ad/74-25-05/models.md
Every aircraft: https://openairdocs.org/ad/74-25-05/aircraft.md

Its text cites no advisory circulars or STCs.

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