# AD 48-29-01: Fuel Pump Drain

- 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- Superseded by: Nothing supersedes this AD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/5B5718DDA4F5C49386256A56006EF6B1.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/48-29-01

## The airworthiness directive

48-29-01 NAVION: Applies to All Airplanes Employing Carter Engine Driven Fuel Pumps Not Presently Equipped With Vent Drain Lines.

To be accomplished as soon as possible but not later than October 15, 1948.

Several instances of rupture of the main diaphragm of Carter fuel pumps have occurred. This is considered a fire hazard, since fuel can then squirt from the pump breather hole onto the engine. To correct this condition the pump breather should be provided with an overboard drain to carry fuel clear of the airplane if the diaphragm ruptures. Before installing the drain line, the fiber screen and snap ring must be removed from the pump breather opening. The drain line should vent into a low pressure area so that any fuel leaving this drain will not be in the proximity of any engine or cabin heater exhaust and will not contact the airplane or enter any air intake line, in ground or flight operation.

(Ryan Navion Service Letter No. 47 covers this same subject.)

## 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/48-29-01/models.md
Every aircraft: https://openairdocs.org/ad/48-29-01/aircraft.md

Its text cites no advisory circulars or STCs.

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