Single-engine failure on a scheduled passenger flight in Finland

Incident overview and flight details On 15 October 2021, a scheduled passenger flight operated by Budapest Aircraft Services Ltd (BASe Airlines) under the Karhu Aero brand departed Pori Airport (EFPO) for Helsinki-Vantaa (EFHK). The aircraft was an Embraer EMB-120ER with registration HA-FAL, flight number BPS692. The crew consisted of two pilots, one cabin crew member, and six passengers. The aircraft was airworthy at the time of the incident. ## Sequence of events After takeoff from Pori, the aircraft was climbing toward flight level 170. At 07:48 local time, the crew contacted air traffic control and reported climbing through flight level 84 toward flight level 170. At flight level 170, the pilots observed light icing and turbulence and requested a lower altitude. When the captain moved the power levers back to reduce power, the right engine's torque and fuel flow indicators dropped significantly. The right engine's torque was nearly zero, and fuel flow decreased from 230 kg/h to 70 kg/h. Moving the power levers forward did not restore power. The right engine remained running but produced no thrust and caused light vibration in the cockpit. The crew declared an emergency at 07:51 and continued toward Helsinki-Vantaa. At 07:55, they shut down the right engine in accordance with the Quick Reference Handbook (QRH). Air traffic control cleared the aircraft to descend to flight level 100 and perform an ILS approach to runway 15. The aircraft landed on runway 15 at 08:15. ## Technical findings According to the aircraft's logbook, the right engine's parameters dropped and the engine was shut down during level flight. The operator's mechanic determined that the power loss was caused by a failure of the right engine's P3 line. Both engines are equipped with a Hydromechanical Metering Unit (HMU), which regulates fuel flow based on P3 pressure data and power lever position. The HMU is calibrated so that P3 pressure data primarily determines the fuel flow limits. When the P3 line failed, the HMU set the right engine's fuel flow to its minimum value, reducing engine power to near idle levels without any warning system indication in the cockpit. After the P3 line failure, moving the power lever had no effect on fuel flow or engine power. The mechanic repaired the fault and performed a test run; the aircraft was declared airworthy. ## Emergency response and consequences Emergency services were alerted at 07:56 with an “air traffic accident risk” notification. The response included 13 fire service and six first-aid units; 10 fire service and three first-aid units arrived at Helsinki-Vantaa. After landing, the alerts were cancelled at 08:17. The operator cancelled the remaining flights scheduled that day for the same aircraft and crew. There were no injuries, material, or environmental damage. The aircraft was ferried back to Pori on 16 October 2021 and resumed scheduled operations on 18 October 2021.