Airworthiness Directive · Amendment 39-21920 · Reciprocating engine power section
Austro Engine GmbH Engines
This AD applies to Austro Engine GmbH E4 and E4P model diesel piston engines equipped with either:
(1) A cylinder head having part number (P/N) E4A-12-500-000, installed in combination with high-pressure pump (HPP) driving gear P/N E4A-30-000-601 (any revision), P/N E4A-30-000-201 rev. AB.1, or P/N E4A-30-000-201 with a serial number (S/N) listed in Chapter 1.4, Table 1 of Austro Engine Mandatory Service Bulletin No. MSB-E4-036/1, Revision No. 1, dated December 14, 2021 (MSB-E4-036/1); or
(2) An HPP driving gear, having P/N E4A-30-000-201, with an S/N listed in Chapter 1.4, Table 1 of Austro Engine MSB-E4-036/1.
The FAA is superseding Airworthiness Directive (AD) 2021-22-20 which applied to certain Austro Engine GmbH E4 and E4P model diesel piston engines. AD 2021-22-20 required, for engines with an affected cylinder head, inspection of the high pressure pump (HPP) driving gear and, depending on the results of the inspection, replacement of the HPP driving gear with a part eligible for installation. AD 2021-22-20 also required, for engines with an affected HPP driving gear, replacement of the HPP driving gear before further flight or within a certain number of flight hours, depending on the engine configuration and number of affected engines installed. This AD requires, for engines equipped with a certain cylinder head and HPP driving gear combination, removal, inspection, and replacement of the HPP driving gear before further flight and, depending on the inspection findings, replacement of the HPP shaft, cylinder head, camshaft gear, or inlet/outlet camshaft bushing. This AD also requires, for engines with an affected HPP driving gear, replacement of the HPP driving gear before further flight or within a certain number of flight hours, depending on the engine configuration and number of affected engines installed. This AD was prompted by reports of failure of the HPP driving gear and a subsequent determination that a batch of HPP driving gears may have been damaged during assembly. This AD was also prompted by an investigation which found that certain cylinder heads installed in combination with certain HPP driving gear on the same engine may cause damage to the HPP driving gear. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For engines equipped with a cylinder head and HPP driving gear combination identified in paragraph (c)(1) of this AD, before further flight after the effective date of this AD, remove the HPP driving gear and replace it with an HPP driving gear eligible for installation using paragraphs 2.1.1 through 2.1.4., Removal and inspection of the HPP driving gear, of Austro Engine MSB-E4-036/1.
(2) Before further flight after performing the required actions in paragraph (g)(1) of this AD, visually inspect the removed HPP driving gear using the criteria in paragraph 7. Appendix II, Table 6, of Austro Engine MSB-E4-036/1.
(3) If, based on the visual inspection required by paragraph (g)(2) of this AD, the HPP driving gear does not meet the acceptable condition criteria in paragraph 7. Appendix II, Table 6, of Austro Engine MSB-E4-036/1, before further flight, visually inspect the HPP shaft, cylinder head, camshaft gear, and inlet/outlet camshaft bushing using the criteria in paragraph 7. Appendix II, Table 7, of Austro Engine MSB-E4-036/1.
(4) If, based on the visual inspection required by paragraph (g)(3) of this AD, the HPP shaft, cylinder head, camshaft gear, or inlet/outlet camshaft bushing do not meet the acceptable condition criteria in paragraph 7. Appendix II, Table 7, of Austro Engine MSB-E4-036/1, before further flight, remove any part not meeting the acceptable condition criteria and replace with a part eligible for installation.
(5) For engines equipped with an affected HPP driving gear identified in paragraph (c)(2) of this AD, within the compliance time specified in Table 1 to paragraph (g)(5) of this AD, as applicable, replace the HPP driving gear with an HPP driving gear eligible for installation.
(1) For the purpose of this AD, an HPP driving gear eligible for installation is:
(i) An HPP driving gear that is not identified in paragraph (c)(2) of this AD; or
(ii) An HPP driving gear that does not create a cylinder head and HPP driving gear combination identified in paragraph (c)(1) of this AD.
(2) For the purpose of this AD, an HPP shaft, cylinder head, camshaft gear, and inlet/outlet camshaft bushing eligible for installation is:
(i) An HPP shaft, cylinder head, camshaft gear, and inlet/outlet camshaft bushing that meets the acceptable condition criteria in paragraph 7. Appendix II, Table 7, of Austro Engine MSB-E4-036/1; or
(ii) An HPP shaft, cylinder head, camshaft gear, and inlet/outlet camshaft bushing that is a new (zero hour) part.
(3) For the purpose of this AD, Engine Group 1 is Austro Engine E4 model engines in configuration “-A” installed on single engine airplanes.
(4) For the purpose of this AD, Engine Group 2 is Austro Engine E4 model engines in configuration “-B” or “-C” and Austro Engine E4P model engines installed on twin-engine airplanes.
The reporting instructions specified in paragraph 7. Appendix II, Tables 6 and 7, of Austro Engine MSB-E4-036/1 are not required by this AD.
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.
