Is AD 2007-05-51 a recurring Airworthiness Directive?

No — AD 2007-05-51 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2007-05-51 apply to?

AD 2007-05-51 applies to Md Helicopters — models MD600N, MD600. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2007-05-51

one-time

Official AD 2007-05-51 · FR doc E7-7438 · 2007-04-20 · airframe

Airworthiness Directives; MD Helicopters Inc. (MDHI) Model MD600N Helicopters

What this AD requires

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2007-05-51, which was sent previously to all known U.S. owners and operators of MDHI Model MD600N helicopters by individual letters. This AD requires, before further flight, a visual and eddy current inspection of each lateral mixer output link assembly (mixer link) and replacing any cracked mixer link. This AD also requires performing an eddy current inspection on each mixer link before installing it on any helicopter. This amendment is prompted by the discovery of 3 cracked mixer links. The actions specified by this AD are intended to detect a crack in the mixer link, which could result in failure of the mixer link and subsequent loss of control of the helicopter.

Which aircraft AD 2007-05-51 applies to

MakesMd Helicopters

ModelsMD600N, MD600

Part-conditional — 600N7636-1, 600N7636-3, 600N7636-9, 600N7636-11.

Applies only when a lateral mixer output link assembly P/N 600N7636-1, -3, -9, or -11 is installed.

Whether AD 2007-05-51 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 2007-05-51 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.