- Published
- December 4, 1956
- Issued
- December 4, 1956
- Model
- PA-23
- Data sheet
- TCDS1A10
- Registered aircraft
- 155 matched by model
- Product
- Aircraft · Small airplane
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed November 21, 2025.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 19 KB | 4e1f5c95…2b738d6 | FAA DRS (API key needed) |
On this page
The airworthiness directive
55-11-02 PIPER: Applies to Model PA-23 Serial Numbers 23-1 to 23-142 Inclusive, 23- 144 to 23-162 Inclusive, 23-164 to 23-173 Inclusive, 23-175 to 23-177 Inclusive, 23-179 to 23- 183 Inclusive, and 23-186.
Compliance required by August 1, 1955.
In order to eliminate excessive pressures in the hydraulic system due to thermal expansion which can result in failure of the hydraulic actuating cylinders, it will be necessary to install thermal relief valves in the landing gear retraction line, landing gear extension line and the flap retraction line. These relief valves are to be installed in accordance with the sketch and instructions contained in Piper Thermal Relief Valve Kit 754 095.
(Piper Service Bulletin No. 136 dated April 26, 1955, covers this same subject.)
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 155
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1954 | 9 |
|---|---|
| 1955 | 34 |
| 1956 | 34 |
| 1957 | 37 |
| 1958 | 1 |
| 1963 | 1 |
39 with no year recorded