AD 56-20-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | C54-DC | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
| aircraft | The Boeing Company | DC-4 | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
| aircraft | The Boeing Company | DC3-G102 | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
| aircraft | The Boeing Company | DC3-G102A | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
| aircraft | The Boeing Company | DC3-G103A | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
| aircraft | The Boeing Company | DC3-G202A | Airworthiness Directives; DOUGLAS All DC3, DC-4 and C54-DC Series Aircraft |
Unsafe Condition
Crankshaft bending failures due to continuous engine operation between 2310 and 2510 r.p.m.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install a placard on the instrument panel stating 'Avoid Continuous Operation of the Engines between 2310 and 2510 r.p.m.' and mark tachometers with a red radial band in that range.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
not later than December 1, 1956
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Douglas DC3 Series, DC-4, and C54-DC Series aircraft powered with Pratt & Whitney Military R-2000 and Twin Wasp D Series engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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