Is AD 2021-22-20 a recurring Airworthiness Directive?

No — AD 2021-22-20 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2021-22-20 apply to?

AD 2021-22-20 applies to Austro Engine Gmbh — models E4, E4P. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2021-22-20

one-time

Official AD 2021-22-20 · FR doc 2021-23842 · 2021-11-01 · reciprocating engine

Airworthiness Directives; Austro Engine GmbH Engines

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for certain Austro Engine GmbH E4 and E4P model diesel piston engines. This AD was prompted by reports of failure of the high-pressure pump (HPP) driving gear and a subsequent determination that a batch of HPP driving gears may have been damaged during assembly. This AD requires, for engines with an affected cylinder head, inspection of the HPP driving gear and, depending on the results of the inspection, replacement of the HPP driving gear with a part eligible for installation. This AD also requires, for engines with an affected HPP driving gear, replacement of the HPP driving gear either before further flight or within a certain number of flight hours after the effective date of this AD. The FAA is issuing this AD to address the unsafe condition on these products.

Which aircraft AD 2021-22-20 applies to

MakesAustro Engine Gmbh

ModelsE4, E4P

Part-conditional — E4A-12-500-000, E4A-30-000-201.

Applies to E4/E4P engines equipped with either a cylinder head P/N E4A-12-500-000 (affected cylinder head), or a high-pressure pump (HPP) driving gear P/N E4A-30-000-201 with an S/N listed in Chapter 1.4, Table 1 of Austro Engine MSB-E4-034/3, Revision No. 3 (affected HPP driving gear).

Whether AD 2021-22-20 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 2021-22-20 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.