# AD 47-31-03: Fuel Drain Cock

- Type: Airworthiness directive
- Status: Current
- Products: Sierra Hotel Aero Navion (Army L-17A)
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 373 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BA28DDF08A5BDA9586256A56006EE743.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/47-31-03

## The airworthiness directive

47-31-03 NAVION: (Was mandatory Note 12 of AD-782-3.) Applies to Serial Numbers NAV-4-2 Through NAV-4-1010 Which Incorporate Koehler Model 2250 Fuel Strainers.

To be accomplished not later than November 1, 1947.

To preclude the possibility of loss of fuel pressure due to air leakage into the fuel system through the CCA-1550-1/8 drain cock on the Koehler Model 2250 fuel strainer, remove this draincock and install Whittaker Model 7600-1/8 drain cock.

(NAA Field Service Bulletin No. 32 dated May 1, 1947, covers this rework.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-782](https://openairdocs.org/tcds/A-782): Sierra Hotel Aero Inc.; names 1 of 8 models: Navion (Army L-17A)

## 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: 373 (373 by airframe model, 0 by engine model)
- Makers: North American 203, Ryan 170

Models with the most aircraft:

- [North American NAVION](https://openairdocs.org/model/north-american-navion): 203 aircraft (airframe model)
- [Ryan NAVION](https://openairdocs.org/model/ryan-navion): 170 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/47-31-03/models.md
Every aircraft: https://openairdocs.org/ad/47-31-03/aircraft.md

Its text cites no advisory circulars or STCs.

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