# AD 49-31-01: Emergency Fuel Pump 'O' Rings

- Type: Airworthiness directive
- Status: Current
- Products: Textron 35 and A35
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 425 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/66133E36CF52F04D86256A0800733A73.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/49-31-01

## The airworthiness directive

49-31-01 BEECH: Applies to Models 35 and A35 Aircraft, Serial Numbers D-1 to D-1935, Inclusive, Equipped With Hand Emergency Fuel Pumps Which Have Not Been Modified to Incorporate the Double "O" Ring Shaft Seal, Beech P/N 35-924070.

Compliance required not later than October 1, 1949, and each 100 hours of aircraft operation thereafter.

To prevent possible hazardous loss of engine power resulting from introduction of air into the airplane's fuel system, inspect the hand emergency fuel pump installation for indications of a defective "O" ring shaft seal. A defective shaft seal may be indicated by fluctuating engine fuel pressure, fuel fumes in the cabin or evidence of fuel leaks around the hand pump's shaft. If a defective shaft seal exists, accomplish proper repair or replace the single "O" ring shaft seal with the double "O" ring shaft seal, Beech P/N 35-924070. After the double "O" ring shaft seals are installed, the 100-hour inspection is no longer required.

(Beech Service Bulletin Model 35, No. 14, Model A35, No. 5 dated July 6, 1949, covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-777](https://openairdocs.org/tcds/A-777): Textron Aviation Inc.; names 2 of 9 models: A35, 35

## 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: 425 (425 by airframe model, 0 by engine model)
- Makers: Beech 425

Models with the most aircraft:

- [Beech 35](https://openairdocs.org/model/beech-35): 266 aircraft (airframe model)
- [Beech A35](https://openairdocs.org/model/beech-a35): 159 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/49-31-01/models.md
Every aircraft: https://openairdocs.org/ad/49-31-01/aircraft.md

Its text cites no advisory circulars or STCs.

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