# AD 77-19-03: Main Rotor Retention Straps

- Type: Airworthiness directive
- Status: Current
- Products: MD Helicopters 369D
- Effective: September 27, 1977
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-3038
- Registered aircraft: 211 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2AEBF84A7CAC325C86256A39004EF497.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/77-19-03

## The airworthiness directive

77-19-03 HUGHES HELICOPTERS: Amendment 39-3038. Applies to Hughes Model 369D helicopters, certificated in all categories, which have P/N 369D21200 main rotor hub serial numbers 0001 through 0178 installed.

Compliance required as indicated.

To prevent failure of the main rotor retention straps which can result in loss of a main rotor blade accomplish the following:

A. Before further flight after the effective date of the AD, visually inspect the lead leg of each main rotor retention strap pack, P/N 369D21210, at the inboard ends to determine if two adjacent metallic anti-fretting laminates P/N 369D21271-5, -51, -53 or -55, have been installed on the upper side of the lead leg of any strap pack.

  (1) If two adjacent metallic anti-fretting laminates have been installed, visually inspect to determine if one or both are cracked or have been broken off where they extend from the hub.

    (i) If no anti-fretting laminate is found cracked or broken, repeat the inspections in (1), above, at times in service not to exceed 25 hours. This repetitive inspection can be discontinued when the main rotor hub, P/N 369D21200, has been replaced by a serviceable hub having only one anti-fretting laminate on the upper side of the lead leg of each main rotor strap pack.

    (ii) If any anti-fretting laminate is found cracked or broken, further visually inspect the main rotor retention strap laminates adjacent to the anti-fretting laminates.

  (a) If any strap laminate is broken or cracked, replace the main rotor hub, P/N 369D21200, before further flight.

  (b) If no strap laminate is cracked or broken, replace the main rotor hub, P/N 369D21200, within ten hours time in service.

  (2) If the inspection reveals that only one metallic anti-fretting laminate has been installed on the upper lead leg of each strap pack no further action is required by this AD.

This amendment becomes effective September 27, 1977, for all persons except those to whom it was made effective by telegram dated August 12, 1977, which contained this amendment.

## 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 1 of 12 models: 369D

## 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: 211 (211 by airframe model, 0 by engine model)
- Makers: Hughes Helicopters 207, Summa 4

Models with the most aircraft:

- [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d): 207 aircraft (airframe model)
- [Summa 369D](https://openairdocs.org/model/summa-369d): 4 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/77-19-03/models.md
Every aircraft: https://openairdocs.org/ad/77-19-03/aircraft.md

Its text cites no advisory circulars or STCs.

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