Is AD 2016-04-21 a recurring Airworthiness Directive?

Yes — AD 2016-04-21 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2016-04-21 apply to?

AD 2016-04-21 applies to Boeing — models DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2016-04-21

recurring

Official AD 2016-04-21 · FR doc 2016-04035 · 2016-03-01 · airframe

Airworthiness Directives; The Boeing Company Airplanes

What this AD requires

We are superseding Airworthiness Directive (AD) 2008-26-07 for all The Boeing Company Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8- 32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 airplanes; Model DC-8-50 series airplanes; Model DC-8F-54 and DC-8F-55 airplanes; Model DC-8-60 series airplanes; Model DC-8-60F series airplanes; Model DC-8-70 series airplanes; and Model DC-8-70F series airplanes. AD 2008-26-07 required repetitive inspections of the lower skin and stringers at certain stations, and corrective actions if necessary. This new AD continues to require the actions specified in AD 2008-26-07 and also requires an eddy current high frequency (ETHF) inspection for cracks of the fastener open holes common to the lower skins, stringers, and splice fittings at a certain station; installation of external doublers and fasteners and repetitive eddy current low frequency (ETLF) inspections around the fasteners for any crack; and corrective actions if necessary. This AD was prompted by certain mandated programs intended to support the airplane reaching its limit of validity of the engineering data that support the established structural maintenance program. We are issuing this AD to detect and correct cracks in the lower skins, stringers, and fastener holes of the splice fittings, which could result in the loss of structural integrity of the airplane.

Repetitive inspection. Re-inspect. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 2016-04-21 applies to

MakesBoeing

ModelsDC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, DC-8-43, DC-8-51, DC-8-52, DC-8-53, DC-8-55, DC-8F-54, DC-8F-55, DC-8-61, DC-8-62, DC-8-63, DC-8-61F, DC-8-62F, DC-8-63F, DC-8-71, DC-8-72, DC-8-73, DC-8-71F, DC-8-72F, DC-8-73F, DC-8

Whether AD 2016-04-21 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 2016-04-21 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.