# AD 55-26-02: Fuel Pumps

- Type: Airworthiness directive
- Status: Current
- Products: Thompson Products Fuel Pumps
- Superseded by: Nothing supersedes this AD
- Product type: Appliance
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D12B94DD2484331B86256A33006FF304.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/55-26-02

## The airworthiness directive

55-26-02 THOMPSON ENGINE DRIVE FUEL PUMPS: Applies to All Thompson TF-1100-2 and TF-1100-M2 Pumps.

Compliance required as indicated.

To prevent TF-1100 fuel pump failure resulting from excessive drive pin wear, accomplish the following:

1. Remove pump from certificated airplanes and replace with Thompson TF-1900 pump having larger diameter drive pin not later than August 1, 1956. TF-1100 pumps may be converted to TF-1900 pumps when modified in accordance with Thompson Service Bulletin ESD-182A and Amendment ESD-182B.

2. Until installation of the TF-1900 pump, the drive pin (Thompson Part No. TF-1191) in the TF-1100 pumps should be replaced with an unused pin at the next 100-hour aircraft inspection and each 100 hours thereafter. At the time of pin replacement, inspect the drilled hole in the TF-1100 rotor for excessive elongation and, if necessary, replace rotor.

(Thompson Products Service Bulletin ESD-176A covers this same subject.)

This supersedesAD 55-19-02.

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

## NTSB investigations that cite this AD (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB SEA01LA115](https://openairdocs.org/ntsb/SEA01LA115), Jun 9, 2001: Beech E35 (N7362B), Eastsound, WA, substantial damage. Probable cause: Failure of the engine driven fuel pump due to a worn snap ring which resulted in a loss of engine power during initial climb. Failure to comply with Service Bulletin inspection instructions, and…

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