What happened
On February 24, 2016, a Cirrus SR-22T was conducting a night flight under IFR conditions from Lublin (EPLB) to Poznań-Ławica (EPPO). While cruising at FL140, the pilot observed irregular engine operation. The pilot attempted to rectify the issue by switching fuel tanks, adjusting boost pressure, and altering the mixture settings, but none of these actions resolved the problem. Despite the engine not losing significant power, the pilot suspected fuel icing due to the ambient temperature of -29°C.
In an attempt to mitigate the risk, the pilot descended to FL100, where the temperature was higher (-12°C), but the engine roughness persisted. The pilot notified Warsaw Approach Control and requested a precautionary landing at Łódź-Lublinek (EPLL). During communications with the Łódź Tower, the pilot initially did not classify the situation as an emergency because the engine was maintaining sufficient power and the flight remained stable. Before landing, the pilot confirmed that the Cirrus Airplane Parachute System (CAPS) was armed and functional down to 1,200 feet AMSL. The aircraft landed safely at EPLL.
The investigation
Following the landing, a ground engine test was performed. When the magnetos were switched to the left position, engine parameters remained stable. However, switching to the right position caused the engine to stumble and misfire. After allowing the engine to cool for several minutes and restarting, the same symptoms occurred at low RPM. The investigation, conducted by the operator's internal commission, focused on identifying the source of the malfunction and reviewing maintenance procedures.
Findings
- The investigation established that the failure of the right magneto was the cause of the engine irregularities.
- A pre-flight engine test conducted at the departure airport (EPLB) had shown no abnormalities.
- The maintenance organization verified the faulty magneto and reported the incident to the manufacturer.
- An audit of the maintenance organization's repair and replacement procedures for magnetos revealed no irregularities.