- Models
- DC-7, DC-7B, DC-7C
- Data sheet
- TCDS4A10
- Registered aircraft
- 5 matched by model
- Product
- Aircraft · Large 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 | d9000312…4983a0d | FAA DRS (API key needed) |
On this page
The airworthiness directive
59-06-02 DOUGLAS: Applies to All Model DC-7 Series Aircraft.
Compliance required by first block overhaul after receipt of parts but not later than December 1, 1959.
Several instances have occurred wherein the green indicator light for one of the main landing gear failed to go on when the landing gears were extended. In one case, after landing, it was noted that the left gear downlatch was not fully engaged and the ground lock safety pin could not be installed. Subsequent investigation and laboratory tests revealed that the orifice check valve could malfunction due to contaminants in the hydraulic fluid of sufficient quantity and size (approximately 0.003-inch diameter) and thereby prevent full extension of the gear.
To overcome this difficulty, remove existing orifice check valve assembly, P/N 4498423-503 (Mineral Oil Aircraft), or P/N 4498423-5503 (Skydrol Aircraft), from each main landing gear actuating cylinder and replace with new orifice check valve assembly, P/N 2230565-5-093 (Mineral Oil Aircraft), or P/N 4481262-5-093 (Skydrol Aircraft). (Douglas Service Bulletin DC-7 No. 353 dated January 30, 1959, 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 · 5
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1957 | 1 |
|---|---|
| 1958 | 2 |
2 with no year recorded