AD 51-01-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | DC-6 | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
| aircraft | The Boeing Company | DC-6A | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
| aircraft | The Boeing Company | DC-6B | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
Unsafe Condition
Broken studs at the front spar lower and upper fittings at wing joint Station 421 and cracks in lower and upper forward front spar fittings (P/N 4332884, -1, 4332885, -1) approximately 2 inches outboard of fitting face.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect for broken studs and cracks at specified fittings every 300 flight hours. Replace broken studs with parts having threads rolled after heat treat, install bolts with threads rolled after heat treat at center spar, and replace fittings with newly designed heavier P/N 4397872/-1 and 4397873/-1. Allow temporary replacement with old design fittings until 8,000 hours service, then spotface new fittings. Continue inspections until permanent replacements are done by January 1, 1952.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Not later than January 1, 1952
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Douglas DC-6, DC-6A, DC-6B aircraft (all serial numbers)
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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