# AD 57-08-02: Parker Check Valve

- Type: Airworthiness directive
- Status: Current
- Products: Scotts-Bell 47 47B3, 47D, 47D1, 47G and 47H-1
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Registered aircraft: 119 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B00DA6CD5EFC2B3886256A34004F9E8E.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/57-08-02

## The airworthiness directive

57-08-02 BELL: Applies to All Models 47B3, 47D, 47D1, 47G, and 47H1 Helicopters Equipped With Parker Check Valves in the Oil System.

Compliance required at next oil change and every 25 hours thereafter until replacement is accomplished.

Several failures of the hinge in the oil system Parker check valve, P/N 1111-517703, 1111-517704, or 1111-517744, have occurred resulting in restriction of the flow of oil from the pump. To preclude recurrence of such failures, the following must be accomplished:

1. At the next oil change and every 25 hours thereafter, remove, disassemble, and inspect the oil system Parker check valve, P/N 1111-517703, 1111-517704, or 1111-517744, for wear or failure of the hinge and freedom of operation. If defects are found, replace the valve.

2. James Pond Clark check valve, P/N 879A-10TT, has been approved as a replacement valve. The 25-hour inspection outlined above may be discontinued when the valve is installed.

(Bell Service Bulletin No. 119 dated March 15, 1957, covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H-1](https://openairdocs.org/tcds/H-1): Scott's-Bell 47 Inc; names 5 of 9 models: 47H-1, 47B3, 47D1, 47D, 47G

## 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: 119 (119 by airframe model, 0 by engine model)
- Makers: Bell 112, Bell-K-Copter 2, Bell Kitz Kopters 1, Bell-Allied Helicopter 1, Bell-Carson 1, Bell-Shippey 1, Continental Copters 1

Models with the most aircraft:

- [Bell 47G](https://openairdocs.org/model/bell-47g): 55 aircraft (airframe model)
- [Bell 47D1](https://openairdocs.org/model/bell-47d1): 47 aircraft (airframe model)
- [Bell 47H-1](https://openairdocs.org/model/bell-47h-1): 6 aircraft (airframe model)
- [Bell 47D](https://openairdocs.org/model/bell-47d): 4 aircraft (airframe model)
- [Bell-K-Copter 47G](https://openairdocs.org/model/bell-k-copter-47g): 2 aircraft (airframe model)
- [Bell Kitz Kopters 47D1](https://openairdocs.org/model/bell-kitz-kopters-47d1): 1 aircraft (airframe model)
- [Bell-Allied Helicopter 47D1](https://openairdocs.org/model/bell-allied-helicopter-47d1): 1 aircraft (airframe model)
- [Bell-Shippey BELL 47G](https://openairdocs.org/model/bell-shippey-bell-47g): 1 aircraft (airframe model)
- [Bell-Carson 47G](https://openairdocs.org/model/bell-carson-47g): 1 aircraft (airframe model)
- [Continental Copters 47G](https://openairdocs.org/model/continental-copters-47g): 1 aircraft (airframe model)

All 10 models: https://openairdocs.org/ad/57-08-02/models.md
Every aircraft: https://openairdocs.org/ad/57-08-02/aircraft.md

Its text cites no advisory circulars or STCs.

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