AD 2011-18-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Lycoming | Engines Model IO-720-A1B Reciprocating | Airworthiness Directives; Lycoming Engines Model IO-720-A1B Reciprocating Engines |
Unsafe Condition
Failure of a crankshaft due to incorrect parts installed, specifically improper counterweight washers.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove four cylinders from one side of the engine, inspect the crankshaft counterweight washers for correct dimensions, and replace the crankshaft assembly if any washers are non-conforming.
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Compliance Time
Before further flight after the effective date of this AD.
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Affected Aircraft
Lycoming Engines Model IO-720-A1B reciprocating engines, serial numbers L-1457-54A and L-1458-54A, last known installed in a Beech U-8F (Queen Air) N51779.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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