Airworthiness Directive 85-21-51
one-timeAD 85-21-51 · 1985-01-01 · airframe
Airworthiness Directives; 49 U.S.C. 1354(a) 1421 and 1423; 49 U.S.C. 106(g) (Revised Pub. L. 97-449. January 12, 1963); and 14 CFR 11.89. 2. By adding the f
Which aircraft AD 85-21-51 applies to
Makes49 U S C 1354 1421 And 1423 49 U S C 106 And 14 Cfr 11 89 2 By Adding Following New Airworthiness Directive Regulatory 106 And 14 Cfr 11 89 \N\N\T2 By Adding Following New Airworthiness Directive 85-21-51 Boeing Applies To Boeing
Models767-200
Whether AD 85-21-51 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 85-21-51 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 →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.