# AD 53-24-04: Fuel-Hydraulic Lines

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-18, PA-20 and PA-22
- Published: December 4, 1956
- Issued: December 4, 1956
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 1,032 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1EEB21ADF21EF98A8625698B007645EE.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/53-24-04

## The airworthiness directive

53-24-04 PIPER: Applies to PA-18, Serial Numbers 18-1 to 18-3000 Inclusive; PA-20, Serial Numbers 20-1 to 20-928 Inclusive; and PA-22, Serial Numbers 22-1 to 22-1689 Inclusive.

Compliance required not later than February 1, 1954.

In order to preclude the possibility of loss of fuel and hydraulic oil and fire in flight caused by chafing of these lines between the firewall and muffler, the following should be accomplished:

  (a) To prevent contact with the muffler, reroute the fuel primer line, and wheel brake hydraulic line if necessary, so that they do not pass behind the muffler.

  (b) Use clamps to fasten the lines to the firewall to prevent movement and vibration of these lines.

(Piper Aircraft Corp. Service Letter No. 213 covers this alteration.)

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A2](https://openairdocs.org/tcds/1A2): Piper Aircraft Inc.; names 1 of 18 models: PA-18
- [TCDS 1A4](https://openairdocs.org/tcds/1A4): Piper Aircraft Inc.; names 1 of 6 models: PA-20
- [TCDS 1A6](https://openairdocs.org/tcds/1A6): Piper Aircraft Inc.; names 1 of 8 models: PA-22

## 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: 1,032 (1,032 by airframe model, 0 by engine model)
- Makers: Piper 1,030, David B Piper 1, Piper-Root 1

Models with the most aircraft:

- [Piper PA-18](https://openairdocs.org/model/piper-pa-18): 477 aircraft (airframe model)
- [Piper PA-22](https://openairdocs.org/model/piper-pa-22): 277 aircraft (airframe model)
- [Piper PA-20](https://openairdocs.org/model/piper-pa-20): 276 aircraft (airframe model)
- [David B Piper PA18 REPLICA](https://openairdocs.org/model/david-b-piper-pa18-replica): 1 aircraft (airframe model)
- [Piper-Root PA-18 SUPER CUB](https://openairdocs.org/model/piper-root-pa-18-super-cub): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/53-24-04/models.md
Every aircraft: https://openairdocs.org/ad/53-24-04/aircraft.md

Its text cites no advisory circulars or STCs.

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