What happened
On September 21, 2018, a pilot and a passenger departed from EPBC in an AT-3 R100 powered by a Rotax 912 iS engine. The flight was being conducted as part of the pilot's flight hour building requirements for a command rating.
During the climb, at an altitude of approximately 900 ft, warning lights for both Line A and Line B illuminated, indicating that engine parameters had exceeded permissible limits. Simultaneously, the pilot observed a large amount of coolant escaping from the engine compartment. The pilot immediately declared an engine failure, returned to the aerodrome, and landed on runway 2 and 28.
Data retrieved from the Engine Monitoring Unit (EMU) revealed that engine oil and cylinder head temperatures had been within the warning (yellow) range for 7 minutes and 28 seconds and 9 minutes and 28 seconds, respectively. Furthermore, both parameters had exceeded the maximum (red) limits: oil temperature was above the limit for 2 minutes and 28 seconds, while cylinder head temperatures remained above the limit for 8 minutes.
The investigation
The investigation focused on the engine's monitoring system and the pilot's actions. While the pilot had 6 hours of experience in the AT-3 model, this was his first flight in the specific version equipped with the EMU electronic display. The investigation established that the pilot had not familiarized himself with the operation or the monitoring procedures of the engine parameter system prior to the flight, which prevented him from utilizing the EMU to identify the specific parameters corresponding to the warnings.
Additionally, the investigation determined that the pilot had performed the takeoff with the air intake shutters closed. According to operating instructions, both the radiator air intake shutters and the oil cooler shutters should be opened before takeoff once the engine oil temperature reaches 50°C. The meteorological conditions on the day of the incident did not necessitate closed shutters.
Findings
- The primary cause of the incident was the takeoff with closed air intake shutters.
- The closed shutters led to the rise in cylinder head and oil temperatures to unacceptable levels.
- A contributing factor was the pilot's lack of familiarity with the operation and monitoring of the engine parameter system.
- The incident could have been prevented if the pilot had monitored the engine parameters following the initial warnings and immediately opened the shutters, reduced engine RPM, and initiated a rapid descent if possible.
Safety action
- Additional training has been conducted for pilots regarding the use of the Rotax 912 iS engine (injection version with EMU) and the monitoring of its operating parameters.