# AD 51-04-01: Fuel Vent Line Check Valve

- Type: Airworthiness directive
- Status: Current
- Products: Martin-Marietta 202
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/59D5EEAACC90B76A8625698A00730ECA.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/51-04-01

## The airworthiness directive

51-04-01 MARTIN: Applies to All Model 202 Aircraft.

Compliance required not later than April 1, 1951.

In order to eliminate a fire hazard due to the possibility of flow from the tank to the engine compartment in case of the failure of the carburetor vapor vent return line, install a swing type check valve at each fuel tank where the vapor vent line attaches to the tank so that flow can take place only toward the fuel tank.

(Martin Service Bulletin No. 138, dated November 30, 1950, covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-795](https://openairdocs.org/tcds/A-795): Martin-Marietta Corporation; names 1 of 2 models: 202

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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