Incident
On July 20, 2024, at approximately 20:40 local time, a near mid-air collision occurred near Muhos, Finland, involving a FinnHEMS helicopter and a small aircraft. The helicopter, an Airbus Helicopters Eurocopter EC145 T2 (aircraft type as specified in the background information), was on an emergency medical service mission with a crew of three: a pilot, a flight assistant, and a doctor. The small aircraft was a high-wing, fixed-gear airplane with white paint and red accent stripes. No radio contact was established with the small aircraft, and it did not appear on the helicopter's Traffic Advisory System (TAS) display, indicating that either it lacked a transponder or its transponder was inactive.
Sequence of Events
The helicopter departed from its Oulu base at 20:30 local time en route to a traffic accident. The pilot made a departure call on Oulu air traffic control frequency and climbed to an altitude of 1,300 feet (approximately 400 meters). The flight route was initially toward Ristijärvi but was later changed toward Kajaani. While the pilot attempted to contact area control to activate a flight plan, the flight assistant was occupied with other duties, leaving the pilot solely responsible for visual lookout. The small aircraft was suddenly sighted approaching from the left and above the helicopter, on a descending flight path nearly perpendicular to the helicopter's direction. The pilot estimated the vertical separation at 100–300 feet (about 30–90 meters) and horizontal separation at 300 feet (about 90 meters). The small aircraft appeared so close that it covered 70% of the helicopter's windshield. The design of the helicopter's cockpit overhead panel had previously obstructed the pilot's view to the upper left, preventing earlier detection.
Upon sighting the aircraft, the pilot announced "I am evading to the left" and executed a sharp descending left turn. The flight assistant then also saw the small aircraft. The doctor, who was on the phone at the time, only noticed the evasive maneuver when he felt the motion. After the event, the pilot reported the incident to area control (ACC). The crew briefly discussed the occurrence in flight and then continued their mission, landing at the Kainuu Border Guard helicopter base in Kajaani at 21:12. The following morning, the pilot contacted the FinnHEMS flight operations manager and filed the required hazard reports.
Aircraft and Equipment
The helicopter was equipped with a Traffic Advisory System (TAS) that receives data from aircraft transponders operating in Mode C or Mode S. The system did not alert the crew to the presence of the small aircraft. According to FinnHEMS procedures, in visual meteorological conditions, evasive action is taken in accordance with methods after visual acquisition of the conflicting traffic. The small aircraft did not respond to radio calls and was not seen on the TAS display; it likely did not have a functioning transponder.
Weather and Environment
The incident occurred in uncontrolled airspace during a clear, sunny summer evening. The Oulu METAR reported CAVOK conditions (ceiling and visibility OK, with visibility of 10 kilometers or more and no significant clouds or weather phenomena). The sun was low on the horizon and shining from the helicopter's direction of travel. The accident investigation authority noted that the small aircraft pilot likely did not see the helicopter because of the sun's glare and the helicopter's position relative to the small aircraft.
Investigation
The Safety Investigation Authority of Finland (Onnettomuustutkintakeskus) investigated the hazard and published its findings on October 16, 2024. The authority did not launch a formal safety investigation into the incident.