- Models
- C54-DC, C54A-DC, C54B-DC, C54D-DC, C54E-DC, C54G-DC, DC-4
- Data sheet
- TCDSA-762
- Registered aircraft
- 4 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 | 21 KB | 1810f952…1d77603 | FAA DRS (API key needed) |
On this page
The airworthiness directive
48-15-03 DOUGLAS: Applies to C-54 and DC-4 Aircraft.
Compliance required by November 1, 1948.
Because of service failures of hydraulic pressure regulator valves, the following must be accomplished:
1. (a) Modify Douglas hydraulic pressure regulator valve P/N 5104005, P/N 5231848, or P/N 5327293 to the equivalent of Douglas regulator P/N 5332857, or
(b) Convert Douglas hydraulic pressure regulator valve P/N 5104005, P/N 5231848, or P/N 5327293 to Douglas regulator P/N 5332857, or
(c) Install Douglas hydraulic pressure regulator P/N 5332857, or
(d) Install Bendix hydraulic pressure regulator P/N 407484, or
(e) Install Air Associates hydraulic pressure regulator valve P/N HC-3600, or
(f) Install Vickers hydraulic pressure regulator valve P/N AA-34551, P/N AA-34552, or P/N AA-34585 which must have the letter "C" or subsequent terminating the regulator serial number, i.e., "Serial No. 0000C," "Serial No. 0000D," etc.
2. Install a hydraulic fluid filter with Purolator core in regulators listed in 1, (a) through (d).
(Douglas Service Bulletin DC-4 No. 22, "Rework of Hydraulic Pressure Regulator Valve" with addendum, "Optional Installation of Hydraulic Pressure Regulators" covers part 1. Douglas Service Bulletin C-54-239, "Installation of Filter in Hydraulic Regulator Operating Line," covers part 2.)
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 4
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.