- Models
- C54-DC, DC-4, DC3-G102, DC3-G102A, DC3-G103A, DC3-G202A
- Registered aircraft
- 8 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 | 19 KB | 0c352d36…1b52f74 | FAA DRS (API key needed) |
On this page
The airworthiness directive
56-20-05 DOUGLAS: Applies to All DC3 Series, DC-4 and C54-DC Series Aircraft Powered With Pratt & Whitney Military R-2000 and Twin Wasp D Series Engines.
Compliance required not later than December 1, 1956.
To avoid crankshaft bending failures, the following placard must be placed on the instrument panel in a conspicuous place: "Avoid Continuous Operation of the Engines between 2310 and 2510 r.p.m." The tachometers must be marked with a red radial band in the above range.
This supersedes AD 48-03-01, which applied only to DC-4 airplanes.
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 8
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1939 | 1 |
|---|---|
| 1940 | 2 |
| 1941 | 1 |
| 1942 | 1 |
| 1943 | 1 |
| 1944 | 1 |
1 with no year recorded