Information on ASTM compliant ROTAX Aircraft Engines
The aircraft related Certification Specification for Light Sport Aircrafts (CS-LSA) permits the usage and installation of an engine which complies with ASTM F2339. Under the above conditions (CS-LSA aircraft with ASTM-compliant engines), the OEM becomes responsible for the certification of that ASTM-compliant engine under the aircraft Type-Certificate as an ASTM-compliant engine is not considered a type certified aeronautical product. Under PART 21 the OEM then becomes responsible for that engine under its aircraft TC. In such a case, the Airworthiness of the entire system in accordance with PART 21 is the responsibility of the OEM and must be carried out jointly with the aircraft. However, there are specific challenges as described in Chapter 3.

Concurrent ASB/SB/SI and SL
In addition to this Service Letter the following documents must be observed and complied with:
in general all relevant Alert Service Bulletins (ASB), Service Bulletins (SB), Service Instructions (SI), Service Letters (SL), Service Instruction Parts and Accessories (SI-PAC) with relevance to perform this maintenance, repair or overhaul task.
SL-912-020/SL-912 i-009/SL-914-018/2ST-012, title “Engine Registration”, current issue.
Information on ASTM compliant ROTAX® Aircraft Engines used in EASA CS-LSA certified aircraft:
Engine type | Serial number |
2-stroke UL aircraft engines | all |
912 (Series not certified) | all |
914 (Series not certified) | all |
912 i (Series not certified) | all |
915 i (Series not certified) | all |
916 i (Series not certified) | all |
INITIAL Airworthiness aspects
The ASTM standard is a self-declaration by ROTAX® and is sufficient to be used when combined with uncertified aircrafts only. As soon as an aircraft OEM combines an ASTM engine with a CS-LSA category aircraft, the aircraft OEM shall become solely responsible for the certification within their aircraft TC and is assigned the full responsibility for showing compliance of the engine in accordance with PART 21 additionally to the aircraft requirements. Furthermore, BRP-Rotax provides a Declaration of Compliance to ASTM F2339 but will not submit any additional substantiation documents which might be required for the certification of the CS-LSA aircraft.
CONTINUED Airworthiness aspects
In case of the ASTM/CS-LSA combination, the Type Certificate (TC)-holder, respectively the aircraft OEM, is solely responsible for ensuring continued airworthiness of their/its product in accordance with PART 21. This also includes the responsibility for creating, distributing and updating any Instructions for Continued Airworthiness as follows:
- Illustrated Parts Catalog (IPC)
- Operators Manual (OM)
- Installation Manual (IM)
- Maintenance Manual Line (MML)
- Maintenance Manual Heavy (MMH)
- Overhaul Manual (OHM)
- (Alert) Service Bulletin (ASB, SB)
- Service Instruction (SI)
- Service Letter (SL)
Maintenance, Repair and Overhaul aspects
Maintenance and repair facilities are strongly advised to check engine certification level (ASTM-compliant or CS-E certified) when installed in CS-LSA aircraft. In the case of a CS-E certified engine, simply follow all current ICAs and the well established procedures of the BRP-Rotax network. In the case of an ASTM compliant engine, please contact the relevant aircraft OEM regarding applicable ICAs, spare parts and maintenance procedures.
The overall BRP-Rotax service network is trained and authorized to work on aircraft engines where the Type Certificate (TC)-holder is BRP-Rotax, this is also in line with local aviation regulations (type specific training). Due to the fact that any combination of a BRP-Rotax ASTM engine and CS-LSA aircraft leads to a situation where there is no engine TC according to PART 21 and the aircraft TC needs to cover the engine, the authorization of the BRP-Rotax service network is invalidated.
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