# AD 51-14-01: Fuel Booster Pump Removal

- 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- Superseded by: Nothing supersedes this AD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/01D38B66E0A1E4F786256A0800731E16.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/51-14-01

## The airworthiness directive

51-14-01 BEECH: Applies to All Models 35 and A35 Aircraft Equipped With Unmodified Adel 20653 Electric Fuel Pump Installation.

Compliance was required as soon as possible, but in any event, not later than April 1, 1949.

To prevent the possibility of air leakage into the airplane's fuel system through a leaking shaft seal of the unmodified 20653 pump, this pump and associated installation components are to be removed from the airplane. Aircraft equipped with a modified fuel booster pump installation, which consists of a modified Adel 20653 electric-driven fuel pump (identified by either a 1/8 inch red band around the pump body, or the suffix "H" in the pump serial number, in series with a modified Thompson TF-1100 engine-driven fuel pump (identified by a "2" or "M2" stamped after the TF-1100 on the nameplate)) installed in accordance with Beech Installation Instructions, revised March 31, 1949, are not affected by this Airworthiness Directive.

(Beech Letter D-49-540 dated January 7, 1949, and Installation Instructions for the Model 35 Electric-Driven Auxiliary Fuel Pump, revised March 31, 1949, covers this same subject.)

This supersedes AD 49-28-02.

## 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/51-14-01/models.md
Every aircraft: https://openairdocs.org/ad/51-14-01/aircraft.md

Its text cites no advisory circulars or STCs.

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