AD 48-15-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | C54-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54A-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54B-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54D-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54E-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54G-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | DC-4 | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
Unsafe Condition
Service failures of hydraulic pressure regulator valves (Douglas P/N 5104005, 5231848, 5327293) could lead to loss of hydraulic pressure regulation.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Modify, convert, or install specified hydraulic pressure regulator valves (Douglas P/N 5332857; Bendix P/N 407484; Air Associates P/N HC-3600; Vickers P/N AA-34551/AA-34552/AA-34585 with 'C' or later serial suffix). Install hydraulic fluid filter with Purolator core in affected regulators.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
November 1, 1948
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Affected Aircraft
Douglas C-54 and DC-4 aircraft with hydraulic pressure regulator valves P/N 5104005, 5231848, or 5327293
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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