Is AD 2009-20-11 a recurring Airworthiness Directive?

No — AD 2009-20-11 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2009-20-11 apply to?

AD 2009-20-11 applies to Boeing — models 737-300, 737-400, 737-500, 737. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2009-20-11

one-time

Official AD 2009-20-11 · FR doc E9-23509 · 2009-10-01 · airframe

Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes Equipped With a Digital Transient Suppression Device (DTSD) Installed in Accordance With Supplemental Type Certificate (STC) ST00127BO

What this AD requires

We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, and -500 series airplanes. This AD requires revising the maintenance program to include new fuel system limitations for airplanes modified in accordance with STC ST00127BO. This AD also requires inspections and checks of the DTSDs and corrective actions, if necessary. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent a potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank fire or explosion and consequent loss of the airplane.

Which aircraft AD 2009-20-11 applies to

MakesBoeing

Models737-300, 737-400, 737-500, 737

Applies only to airplanes equipped with a digital transient suppression device (DTSD) installed in accordance with Supplemental Type Certificate (STC) ST00127BO.

Whether AD 2009-20-11 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 2009-20-11 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.