Overview
On 31 August 2017, at approximately 21:15 local time, a Diamond DA20 aircraft (registration SP-KWG) was conducting a series of night VFR training flights at EPMO. The aircraft was occupied by an instructor and a student pilot. The incident involved a loss of engine power, but the aircraft landed safely and no injuries were reported.
Flight Details
The student pilot, while at an altitude of 300-400 feet, reported a loss of engine power. The instructor took control and observed that the aircraft continued to climb but with noticeably reduced power and vibrations. Temperature indications for cylinder 4 deviated from normal. The instructor declared a technical fault and decided to land on runway 26, which was the opposite direction; no emergency was declared as the engine continued running. The wind was perpendicular to the runway and did not influence the landing direction. After landing and rollout on runway 26, the aircraft taxied via taxiways E and A to the hangar on a running engine.
Investigation Findings
Post-flight inspection and maintenance revealed that the fuel injectors were replaced, along with the oil filter and oil. An engine test run was performed and parameters were checked, after which the aircraft was deemed fit for service. The aircraft was equipped with a flight data recorder, which showed elevated temperatures on cylinder 4. At the 23-minute mark of the flight, cylinder 4 shut down, resulting in the power loss. Throughout the flight, no engine parameters exceeded critical limits. Subsequent visual inspection found no damage to the cylinder walls or piston crown.
Cause
The investigation determined that the loss of engine power and elevated temperature on cylinder 4 were caused by progressive degradation of the injector's efficiency, leading to a lean fuel-air mixture and eventual shutdown of that cylinder.
Actions Taken
The circumstances and corrective actions were communicated internally and externally via safety bulletin KRONIKA SMS No. 09/2017. Additionally, the event and its likely causes were reviewed at a working group meeting in December 2017. No safety recommendations were issued.