# AD 51-19-02: Oil Radiator Hose

- 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- Superseded by: Nothing supersedes this AD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/DCE89B591A22643C8625698B0076422D.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/51-19-02

## The airworthiness directive

51-19-02 PIPER: Applies to Models PA-18 Serial Numbers 18-487 to 18-730 Inclusive; PA-20 Serial Numbers 20-554 to 20-690 Inclusive; and PA-22 Serial Numbers 22-1 to 22-90 Inclusive.

Compliance required by August 31, 1951.

Overage oil radiator hose was installed in an undetermined number of Piper airplanes. Inspect immediately to determine that the proper hose marked with a solid white line and a broken red line and AN H-35 or MIL H-6000 are installed. Defective hose are marked "Aromatic Resistant Gates Vulco" followed by a date with the opposite side marked by a solid white line and broken red line. All defective hose should be replaced as soon as possible but not later than August 31, 1951.

(This information supersedes that in Piper Service Letter No. 165 dated March 23, 1951.)

## 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/51-19-02/models.md
Every aircraft: https://openairdocs.org/ad/51-19-02/aircraft.md

Its text cites no advisory circulars or STCs.

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