Is AD 2000-23-21 a recurring Airworthiness Directive?

No — AD 2000-23-21 is a one-time directive. Verify it was complied with in the aircraft's records.

Airworthiness Directive 2000-23-21

Q: Which aircraft does AD 2000-23-21 apply to?

AD 2000-23-21 applies to Teledyne Continental Motors — models IO-360, TSIO-360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520. Serial/part conditions may narrow it to specific aircraft.

one-time

Official AD 2000-23-21 · FR doc 00-29496 · 2000-11-27 · reciprocating engine

Airworthiness Directives; Teledyne Continental Motors IO-360, TSIO-360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, and TSIOL-550 Series Reciprocating Engines

What this AD requires

This amendment supersedes emergency airworthiness directive (AD) 2000-08-51. Emergency AD 2000-08-51 was sent to all known U.S. owners and operators of Teledyne Continental Motors (TCM) IO-360, TSIO- 360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, and TSIOL-550 series reciprocating engines by individual letters. This amendment requires removing a core sample of material from the propeller mounting flange of certain crankshafts, and sending the core sample to TCM for evaluation. This amendment is prompted by reports of crankshaft failures, and by the addition of additional crankshaft serial numbers (SN) that have been added to the suspect population. The actions specified by this AD are intended to prevent fracture of the crankshaft connecting rod journal, which could result in total engine power loss, in-flight engine failure and possible forced landing.

Which aircraft AD 2000-23-21 applies to

MakesTeledyne Continental Motors

ModelsIO-360, TSIO-360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, TSIOL-550

Applies to engines assembled, rebuilt, or overhauled using a crankshaft manufactured between April 1, 1998 and March 31, 2000, listed by specific engine and crankshaft serial number in TCM Mandatory Service Bulletin (MSB) 00-5C, dated October 10, 2000 (individual SN list not provided in source text).

Whether AD 2000-23-21 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 2000-23-21 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.