Is AD 51-01-01 a recurring Airworthiness Directive?

No — AD 51-01-01 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 51-01-01 apply to?

AD 51-01-01 applies to The Boeing Company, Douglas — models DC-6, DC-6A, DC-6B. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 51-01-01

one-time

AD 51-01-01 · 1951-01-01 · airframe

Airworthiness Directives; Letter DC-6 No. 61 covers this same subject. Refer to Douglas Service Letter No. 66, Supplement No. 2 dated July 18, 1951, for win

Which aircraft AD 51-01-01 applies to

MakesThe Boeing CompanyDouglas

ModelsDC-6, DC-6A, DC-6B

Concerns wing alignment at Station 421; see Douglas Service Letter DC-6 No. 61 and Douglas Service Letter No. 66, Supplement No. 2, dated July 18, 1951.

Whether AD 51-01-01 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 51-01-01 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.