Airworthiness Directive · Amendment 39-22852 · Engine
Austro Engine GmbH Engines
This AD applies to Austro Engine GmbH (Austro) Model E4 and E4P engines with an installed piston having part number E4A-72-400-000.
The FAA is adopting a new airworthiness directive (AD) for certain Austro Engine GmbH (Austro) Model E4 and E4P engines. This AD was prompted by reports of engine failures and an investigation where cracks were discovered on the pistons. This AD requires repetitive borescope inspections (BSIs) for cracks on the pistons, and, if necessary, removal from service and replacement of the piston, and a fuel sample analysis for water contamination and, if contamination is found, replacement of the high-pressure pump (HPP), injectors, and fuel rails. The FAA is issuing this AD to address the unsafe condition on these products.
(1) At the applicable times specified in paragraphs (g)(1)(i) through (iv) of this AD, do repetitive borescope inspections (BSIs) of each affected piston for cracks on the piston in accordance with paragraph 2.1.2 “Accomplishment/Instructions” of Austro Mandatory Service Bulletin No. MSB-E4-043/0, dated August 27, 2024.
(i) For Configuration E4A and E4P engines with less than 100 flight hours (FHs) since installation as of the effective date of this AD: Inspect within 100 FHs since installation and thereafter at intervals not to exceed 50 FHs.
(ii) For Configuration E4A and E4P engines with 100 FHs or more since installation as of the effective date of this AD: Inspect before further flight and thereafter at intervals not to exceed 50 FHs.
(iii) For Configuration E4B and E4C engines with less than 200 FHs since installation as of the effective date of this AD: Inspect within 200 FHs since installation and thereafter at intervals not to exceed 100 FHs.
(iv) For Configuration E4B and E4C engines with 200 FHs or more since installation as of the effective date of this AD: Inspect before further flight and thereafter at intervals not to exceed 100 FHs.
(2) If during any BSI required by paragraph (g)(1) of this AD, any crack is found, before further flight, do the following:
(i) Remove from service and replace the piston. Replacement of the engine core includes piston replacement and would satisfy this requirement.
(ii) Collect a fuel sample from the high-pressure pump (HPP) fuel return line and do a fuel analysis for water contamination.
(iii) If during any fuel analysis required by paragraph (g)(2)(ii), any water contamination is found, remove from service and replace the HPP, injectors, and fuel rails.
For the purpose of this AD:
(1) “Configuration E4A engines” are Model E4 engines with an engine serial number (ESN) that begins with “E4-A-...”
(2) “Configuration E4B engines” are Model E4 engines with an ESN that begins with “E4-B-...”
(3) “Configuration E4C engines” are Model E4 engines with an ESN that begins with “E4-C-...”
(4) “Configuration E4P engines” are Model E4P engines with an ESN that begins with “E4P-B-...” or “E4P-C-...”
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
