History of the Flight
On 22 August 2017, a student pilot departed from runway 22 at Larnaca International Airport in an Aquila AT01 aircraft, registration 5B-CLP, for a solo VFR flight to the MARKI training area. Shortly after turning right, the engine began vibrating. The pilot requested permission from Larnaca Tower to rejoin the traffic pattern for a full-stop landing. The Control Tower declared a "local standby" to assist the aircraft. The aircraft landed on runway 22 at 09:55 local time and vacated via taxiway "E". The pilot shut down the engine on the taxiway, and it could not be restarted. The aircraft was towed by PEGASUS Engineering for maintenance checks.
Damage to Aircraft
No damage to the airframe was sustained. However, the engine was overheated, and one cylinder was found with a broken exhaust valve. The engine temperature sensor was also melted.
Type of Flight
The flight was a VFR solo flight.
Aircraft Information
The aircraft's maintenance schedule was controlled by a Continuing Airworthiness Management Organisation (CAMO), and maintenance was carried out by PEGASUS Engineering, an approved Part 145 Maintenance Organization.
Meteorological Information
Weather conditions were not significant to the incident.
Conclusions
The pilot's action of requesting permission to return for landing after the engine malfunction, without attempting to troubleshoot, was correct. The report noted that if the engine malfunction had occurred later in the intended flight, the outcome could have been catastrophic. Examination of the engine after the incident revealed no coolant in the cooling system. The engine cylinder heads are cooled by liquid coolant, and the cylinder barrels are cooled by ram air. The lack of coolant caused the engine to overheat, resulting in a broken exhaust valve head and a melted temperature sensor.
Safety Recommendations
1. Coolant quantity checks are important for the safe operation of Rotax 912 engines. Since the Aquila AT01 has no access door for pilots or instructors to check coolant quantity before each flight (requiring removal of the top engine cowling), and in view of several common incidents, a daily check by the operator's maintenance organization is recommended to verify coolant quantity and the integrity of the entire cooling system, including hoses and connections. 2. According to the aircraft flight manual, Section 2, Paragraph 2.15 (Temperature limitations), the maximum outside air temperature for take-off is 38°C. This limitation should always be considered, especially during summer months when outside air temperatures exceed this limit.