The aviation industry is currently experiencing an increasing number of faults in aircraft equipped with carburettor engines manufactured by Rotax. Both the German Federal Aviation Office (LBA) and the Swiss Federal Office of Civil Aviation (BAZL) have been focussing on these problems. For some time now, these authorities have been recording an increased number of incident reports relating to these engines, which are used in various aircraft models. It has not yet been possible to conclusively determine the exact causes of these faults.
In order to inform the public and pilots in particular about these safety concerns, the FOCA published "Safety Awareness Notification Data" (SAND for short) on 14 July 2023. This is safety-relevant information and recommendations that are published in informal form and serve as a preliminary stage for possible official official publications such as airworthiness directives. In the current SAND (FOCA SAND 2023-003), the FOCA specifically addresses the increased number of incident reports regarding engine malfunctions in Rotax-powered aircraft and provides initial recommendations for action.
More than a year ago, the LBA called in the European Aviation Safety Agency (EASA), which is responsible for the type certification of aircraft, due to the increasing number of fault reports regarding Rotax engines. Since then, the LBA has been in close contact with the EASA. On 17 March 2023, EASA published a recommendation (SIB Safety Information Bulletin 2023-04) on the modification of the exhaust system for Aquila AT01 aircraft, based on SB-AT01-041.
The possible causes of these engine faults are currently being intensively investigated. The narrow installation space of the engines within the aircraft cowling, the exhaust system, the fuel supply, the fuel quality and the ignition mechanism are being discussed, among other things. To make matters worse, these faults are not reproducible, which makes it difficult to analyse and rectify the problems.
To date, there have been no accidents in Germany due to these malfunctions, although emergency landings have been recorded in the vicinity of take-off aerodromes. It is particularly noticeable that many of these malfunctions occur during the climb phase shortly after take-off, which is considered the most critical phase of a flight.
In total, the LBA has recorded 86 incidents related to Rotax engine problems in the national incident reporting database since 2017. Most of these events occurred during the take-off phase and their number has increased in recent years (from 12 events in 2017-2019 to 8 events in the first half of 2023).
The LBA continues to work intensively on this issue and shares all relevant information with EASA, the manufacturers of the affected aircraft models, aircraft operators and flight schools. Pilots are encouraged to report similar problems in order to contribute to aviation safety. Information on reporting occurrences can be found on the LBA website. It is emphasised that every occurrence report can help to identify and rectify problems in order to make aviation safer overall.
Source references:
LBA - Aviation news
