# AD 73-20-04: Fuel Pump Boost Electrical Circuit

- Type: Airworthiness directive
- Status: Current
- Products: Cessna R172E
- Effective: October 3, 1973
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1726
- Registered aircraft: 98 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/6B555DEC60DD24CE86256A34006462E7.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-20-04

## The airworthiness directive

73-20-04 CESSNA: Amendment 39-1726. Applies to Model R172E (T-41B) Serial Numbers R172-0001 through R172-0256) airplanes.

Compliance: Within 50 hours' time in service after the effective date of this AD, unless already accomplished.

To prevent complete loss of engine power when using the fuel boost pump, accomplish the following:

Modify the fuel boost pump electrical circuit by installing a new boost pump switch, electrical resistors, and placard in accordance with Cessna Service Letter No. SE73-24, dated August 24, 1973, and Service Kit SK172-43, or later FAA-approved revisions, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

This amendment becomes effective October 3, 1973.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 3A17](https://openairdocs.org/tcds/3A17): Textron Aviation Inc.; names 1 of 12 models: R172E

## 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: 98 (98 by airframe model, 0 by engine model)
- Makers: Cessna 98

Models with the most aircraft:

- [Cessna R172E](https://openairdocs.org/model/cessna-r172e): 98 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/73-20-04/models.md
Every aircraft: https://openairdocs.org/ad/73-20-04/aircraft.md

Its text cites no advisory circulars or STCs.

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