- Model
- Navion (Army L-17A)
- Data sheet
- TCDSA-782
- Registered aircraft
- 373 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 May 30, 2024.
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 | 20 KB | 6586a471…c0f1cc1 | FAA DRS (API key needed) |
On this page
The airworthiness directive
47-21-09 NAVION: (Was Mandatory Note 8 of AD-782-3.) Applies to All Serials Up to and Including Number NAV-4-947.
Compliance required prior to September 1, 1947.
Due to malfunctioning of the hydraulic system which has resulted in the failure of components of that system, including actuating cylinders, the following modifications must be accomplished:
(a) If an engine-driven hydraulic pump is installed in the airplane, rework the hydraulic power system to install the manually controlled relief valve, North American P/N 145- 58027, and replace the existing placard "Hyd. System Pull Off" with new placard "Hyd. Power On".
(North American Field Service Bulletin No. 26 covers this same subject.)
(b) Install the swivel head type nose gear actuating cylinder, North American P/N 145-58014.
(North American Field Service Bulletin No. 19 covers this same subject.)
(c) Visually inspect all flap and landing gear actuating cylinders for evidence of cracks or other damage. Any cylinders found to be damaged should be replaced.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 373
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1946 | 78 |
|---|---|
| 1947 | 98 |
| 1948 | 88 |
| 1949 | 23 |
| 1950 | 2 |
| 1951 | 1 |
| 1956 | 1 |
| 1958 | 1 |
| 1959 | 1 |
80 with no year recorded