# AD 74-20-04: Main Rotor Blade

- Type: Airworthiness directive
- Status: Current
- Products: MD Helicopters 369, 369A, 369H, 369HE, 369HM and 369HS
- Effective: September 25, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-1968
- Registered aircraft: 130 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/8AA37D70236B950686256A39004ADF0A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-20-04

## The airworthiness directive

74-20-04 HUGHES HELICOPTERS: Amendment 39-1968. Applies to Hughes Model 369, 369A, 369H, 369HE, 369HS and 369HM helicopters certificated in all categories.

Compliance required within the next 25 hours' of helicopter operation after the effective date of this AD, unless already accomplished within the last 75 hours' of helicopter operation, and thereafter at intervals not to exceed 100 hours' of helicopter operation from the last inspection.

To detect cracks, gouges, nicks and scratches in the main rotor blade trailing edge, accomplish the following:

  (a) Inspect the main rotor blade trailing edge in accordance with Hughes Service Information Notice. No. HN-73, dated August 19, 1974, or later FAA-approved revisions.

  (1) If cracks are found remove blade from service prior to further flight.

  (2) If gouges, nicks and/or scratches are found replace or repair blade prior to further flight in accordance with Hughes Service Information Notice, No. HN-73.

  (b)Equivalent inspection and repair procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region upon submittal of adequate substantiating data.

  (c) Aircraft may be flown to a base for performance of the inspections required by this AD per FAR's 21.197 and 21.199.

This amendment becomes effective September 25, 1974.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H3WE](https://openairdocs.org/tcds/H3WE): MD Helicopters LLC; names 6 of 12 models: 369HS, 369HM, 369HE, 369H, 369 (Army YOH-6A), 369A (Army OH-6A)

## 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: 130 (130 by airframe model, 0 by engine model)
- Makers: Hughes 121, MD Helicopters 6, Hughes/Batto John 1, Hughes/Helicopter Assocs 1, Summa 1

Models with the most aircraft:

- [Hughes 369HS](https://openairdocs.org/model/hughes-369hs): 69 aircraft (airframe model)
- [Hughes 369A](https://openairdocs.org/model/hughes-369a): 32 aircraft (airframe model)
- [Hughes 369A (OH-6A)](https://openairdocs.org/model/hughes-369a-oh-6a): 11 aircraft (airframe model)
- [Hughes 369](https://openairdocs.org/model/hughes-369): 5 aircraft (airframe model)
- [MD Helicopters 369HS](https://openairdocs.org/model/md-helicopters-369hs): 3 aircraft (airframe model)
- [Hughes 369HE](https://openairdocs.org/model/hughes-369he): 3 aircraft (airframe model)
- [MD Helicopters 369HM](https://openairdocs.org/model/md-helicopters-369hm): 2 aircraft (airframe model)
- [Summa 369HS](https://openairdocs.org/model/summa-369hs): 1 aircraft (airframe model)
- [MD Helicopters 369A](https://openairdocs.org/model/md-helicopters-369a): 1 aircraft (airframe model)
- [Hughes/Helicopter Assocs 369A](https://openairdocs.org/model/hughes-helicopter-assocs-369a): 1 aircraft (airframe model)
- [Hughes/Batto John 369A (OH-6A)](https://openairdocs.org/model/hughes-batto-john-369a-oh-6a): 1 aircraft (airframe model)
- [Hughes 369H](https://openairdocs.org/model/hughes-369h): 1 aircraft (airframe model)

All 12 models: https://openairdocs.org/ad/74-20-04/models.md
Every aircraft: https://openairdocs.org/ad/74-20-04/aircraft.md

Its text cites no advisory circulars or STCs.

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