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Airworthiness Directive 2011-18-09

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Official AD 2011-18-09 · FR doc 2011-22244 · 2011-09-14 · reciprocating engine

Airworthiness Directives; Lycoming Engines Model IO-720-A1B Reciprocating Engines

What this AD requires

We are adopting a new airworthiness directive (AD) for certain model IO-720-A1B Lycoming Engines reciprocating engines. This AD requires a crankshaft inspection for certain parts that may be installed. This AD was prompted by the failure of a crankshaft due to incorrect parts installed. We are issuing this AD to prevent engine crankshaft failure and damage to the airplane.

Which aircraft AD 2011-18-09 applies to

MakesLycoming Engines
ModelsIO-720-A1B, IO-720
Serial-conditional — narrows to serials L-1457-54A–L-1457-54A, L-1458-54A–L-1458-54A.

Applies only to the two specific engines by serial number. These engines were last known to be installed in a Beech U-8F (Queen Air), registration N51779, operating in the southern U.S. and Mexico.

Whether AD 2011-18-09 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.

How AD compliance is recorded

A valid compliance record (14 CFR 43.9) states:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.
Date — When the work was done.
Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.
Signature & certificate — The A&P/IA who returned it to service, with certificate number.
Is AD 2011-18-09 complied with on your aircraft?

Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.

Look up a tail number →Read the full directive (Federal Register)

Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.