Airworthiness Directive · Amendment 39-22691 · Austro Engine GmbH Engines
Austro Engine GmbH Engines
This AD applies to Austro Engine GmbH Model E4 and E4P engines with one of the following:
(1) An engine serial number or engine core serial number specified in Table 1 of Austro Engine GMBH Mandatory Service Bulletin No. MSB-E4-042, Revision 0, dated January 31, 2024 (MSB-E4-042), or;
(2) An engine serial number or engine core serial number specified in Table 2 of MSB-E4-042.
The FAA is adopting a new airworthiness directive (AD) for certain Austro Engine GmbH Model E4 and E4P engines. This AD was prompted by reports of engine failures and the determination that certain batches of cap screws, installed on the inner main bearing positions of the engine, were manufactured at the lower end of the material strength tolerance. This AD requires replacing certain cap screws with a part eligible for installation and prohibits installing certain cap screws on any inner main bearing position of any engine. This AD also prohibits installing certain engine cores on any engine unless certain requirements are met. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For engines or engine cores identified in paragraph (c)(1) of this AD, before further flight after the effective date of this AD, remove each cap screw, installed on the inner main bearing positions of the engine, from service and replace it with a part eligible for installation in accordance with paragraph 2.3, “Main Bearing Screws Replacement” of Austro Engine GmbH Work Instruction WI-MSB-E4-042, Revision 0, dated February 2, 2024 (WI-MSB-E4-042).
(2) For engines or engine cores identified in paragraph (c)(2) of this AD, remove each cap screw, installed on the inner main bearing positions of the engine, from service and replace it with a part eligible for installation in accordance with paragraph 2.3, “Main Bearing Screws Replacement” of WI-MSB-E4-042, at the compliance times referenced in paragraph (g)(2)(i) or (ii) of this AD, whichever occurs first:
(i) Within 300 flight hours after first installation on an airplane or since last overhaul, as applicable, or before further flight after the effective date of this AD, whichever occurs later.
(ii) At the next scheduled engine maintenance, after the effective date of this AD.
(1) As of the effective date of this AD, do not install an engine core, having a serial number specified in Table 1 or Table 2 of MSB-E4-042, on any engine, unless the cap screws installed on the inner main bearing positions of that engine core have been replaced with parts eligible for installation in accordance with paragraph 2., Technical Details of MSB-E4-042.
(2) As of the effective date of this AD, do not install cap screws having part number (P/N) E4A-10-100-201 on the inner main bearing positions of any engine.
For the purposes of this AD:
(1) A part eligible for installation is a cap screw, class 12.9, having P/N E4A-10-100-202.
(2) The inner main bearing positions are engine bearing positions 3 through 8 inclusive, as shown in Figure 1, “Main bearing cap screws to be replaced.” of MSB-E4-042.
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.
