Is AD 85-21-04 a recurring Airworthiness Directive?

No — AD 85-21-04 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 85-21-04 apply to?

AD 85-21-04 applies to Maryland Air Industries, Inc. — models F-27, F-27A, F-27B, F-27F, F-27G, F-27J, F-27M, FH-227. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 85-21-04

one-time

AD 85-21-04 · 1985-01-01 · airframe

Airworthiness Directives; This amendment becomes effective November 14, 1985. FOOTER: Maryland Air Industries, Inc. F-27 F-27A F-27B F-27F F-27G F-27J F-27M

Which aircraft AD 85-21-04 applies to

MakesMaryland Air Industries, Inc.

ModelsF-27, F-27A, F-27B, F-27F, F-27G, F-27J, F-27M, FH-227, FH-227B, FH-227C, FH-227D, FH-227E

Source applicability text truncated; amendment became effective November 14, 1985.

Whether AD 85-21-04 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 85-21-04 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 →

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.