Is AD 2012-21-11 a recurring Airworthiness Directive?

No — AD 2012-21-11 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2012-21-11 apply to?

AD 2012-21-11 applies to Bombardier — models CL-600-2B16, CL-601-3A, CL-601-3R, CL-604, CL-600. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2012-21-11

one-time

Official AD 2012-21-11 · FR doc 2012-26075 · 2012-10-30 · airframe

Airworthiness Directives; Bombardier, Inc. Airplanes

What this AD requires

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604 Variants) airplanes. This AD was prompted by reports of deformation at the neck of the pressure regulator body on the oxygen cylinder and regulator assemblies (CRAs), and an electrical wiring harness in the area of the oxygen cylinder with no protective conduit sleeving. This AD requires inspecting to determine if certain oxygen pressure regulators are installed and replacing oxygen CRAs containing pressure regulators that do not meet the required material properties. This AD also requires inspecting for damaged wiring, and repairing or replacing wiring if necessary. We are issuing this AD to prevent rupture of the oxygen cylinder, which in the case of cabin depressurization, would lead to oxygen not being available when required; and to detect and correct unprotected wiring that could chafe against the oxygen system components or surrounding structure in the area, and lead to electrical arcing and an oxygen-fed fire.

Which aircraft AD 2012-21-11 applies to

MakesBombardier

ModelsCL-600-2B16, CL-601-3A, CL-601-3R, CL-604, CL-600

Serial-conditional — narrows to serials 5701–5802, 5804–5808, 5810–5816, 5819–5819, 5822–5822, 5823–?.

Serial number 5823 and all subsequent serial numbers are included (open-ended range).

Whether AD 2012-21-11 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 2012-21-11 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.