Mid-air collisions and near misses (MAC/Airprox)

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Near misses and collisions in the air (MAC/AIRPROX) 2024

In 2024, a total of 68 near-misses between aircraft were reported in Finland or to Finnish aircraft abroad. This number was clearly above the average for 2014–2023 (approximately 41).

There were 40 reported incidents in Finland, which was above the ten-year average (approx. 32). Abroad, 28 incidents were reported, which was more than double the average of previous years (approx. 12).

In none of the cases was there an actual collision, similarly as in previous years. However, eight cases were classified as serious incidents, which was slightly above the long-term average. Five of these occurred abroad and three in Finland. The number of serious incidents abroad was higher than average. In the majority of cases, the other party was a drone flown too high. In addition, two serious incidents occurred when a Finnish aircraft was operating at a foreign uncontrolled aerodrome.

The number of serious incidents in Finland remained below the long-term average. All serious incidents involved situations between manned aircraft that occurred at an uncontrolled aerodrome or in uncontrolled airspace. In previous years, serious incidents caused by drones have been common, but no such incidents have been reported in the last two years.

The Finnish Safety Investigation Authority (OTKES) conducted an investigation into one serious incident  (External link). The incident involved a medical helicopter in uncontrolled airspace near Oulu during the en route phase of the flight. Suddenly, a small aircraft flew very close to the rear left of the helicopter and slightly above it. The helicopter pilot had to make an emergency avoidance maneuver to avoid a collision.

According to the pilot's report, the risk of collision could have been reduced if the other aircraft had had a transponder on, which would have made the small aircraft visible to the helicopter's ACAS system.
 

Commercial air transport

Finnish commercial air transport was involved in 43 near-miss incidents in 2024. The number was clearly above the average for 2014–2023. Of these, 16 incidents occurred in Finland and 27 abroad. The number of incidents reported abroad was significantly above the long-term average, and the numbers have been increasing for several years. The number in Finland was also above the average, but at the same level as in previous years.

In Finland, the location of the incident in almost all cases was Helsinki-Vantaa Airport, which has also been the most common location in previous years. The numbers did not differ significantly from previous years. In the majority of cases, there was a separation minima infringement between aircraft, but the infringements were not very significant. In two cases, the drone was flown too close to commercial air traffic when the aircraft was coming to land.

One near-miss incident in Finland was classified as a serious incident. This was the previously described incident between a medical helicopter and a general aviation aircraft. However, the number of serious incidents remained below the average of previous years.

The most common countries of occurrence abroad were the United Kingdom, Germany, Switzerland and the United States. About a third of all reported incidents abroad occurred in the United Kingdom, while in 2023 the number was almost half.

Of the incidents that occurred abroad, five were classified as serious incidents. Three of these occurred in the UK (London and Manchester), and in all cases the other party was a drone. In addition, one serious incident occurred in Switzerland and one in Austria, both at uncontrolled airfields, when a Finnish small commercial air transport aircraft was approaching to land and had a near miss with local traffic.

Other situations that occurred abroad were typically related to near-miss situations with drones or, for example, to avoidance orders issued by the TCAS system, which reduce the risk of a potential collision. More on the topic of TCAS below.
 

General and recreational aviation

Finnish general and recreational aviation was involved in 18 near-miss incidents in 2024. The number was approximately at the average level for 2014–2023. All incidents occurred in Finland, which has been typical also in previous years. Near-miss incidents abroad have been reported mainly in Spain, where Finnish flight training takes place, but no such incidents were reported last year.

Three of the incidents were classified as serious incidents, and they occurred at uncontrolled aerodromes (Nummela and Räyskälä) or in uncontrolled airspace (Muhos near Oulu). This is in line with the average of previous years, as near-misses in general and recreational aviation lead to an average of three serious incidents per year. Finnish aircraft did not experience any near-misses or serious incidents abroad, which has been quite rare in the past.

In previous years, the most common locations for incidents have been Helsinki-Malmi, Pori, Hyvinkää, Lahti-Vesivehmaa and Nummela. After the closure of Malmi airport, traffic has mainly shifted to nearby uncontrolled airports, and an increase in traffic has been observed especially in Hyvinkää, Lahti-Vesivehmaa and Nummela. However, only isolated near-misses were reported at these airports last year. The majority of incidents occurred in Pori and Tampere-Pirkkala, where general aviation flight training activities are active. The majority of near-misses were related to general aviation.

At uncontrolled airports, where there is no air traffic control to direct traffic, the importance of proper situational awareness is emphasized. In the previous year, 2023, "be seen and be heard" was raised as a special theme in Finnish recreational aviation safety work. More information on the topic can be found, for example, in the presentation materials from that year's Lentoon! seminar  (External link).

The safety bulletins  (External link)have also identified the most typical causes of near-miss situations and considered ways to prevent them. One of the most important safety factors is maintaining situational awareness. According to one safety bulletin:

"The building blocks of situational awareness include trust that others will also act according to common rules, listening to and speaking on the airport radio frequency, and actively observing the airspace."

Unmanned aviation

In 2024, four near-miss incidents involving drones with manned aviation were reported in Finland. The number was clearly below the average for 2014–2023 (approx. 8). The most typical incident was still the flying of a drone in the vicinity of Helsinki-Vantaa Airport at the same time as an aircraft was approaching the runway. However, none of these incidents caused a serious incident to manned aviation.

There was also one reported incident in 2024 where two drones collided during an electrical grid inspection flight. Such collisions between drones have been quite rare so far.

In Finland, the number of near-miss incidents caused by drones remained at a reasonable level last year. On the other hand, the number of incidents where drones were flown without permission in controlled airspace or other airspace requiring permission increased slightly. Unauthorized drone operations, especially near airports, are almost always intentional. A drone can cause serious damage when it collides with a manned aircraft, so every such incident is an unnecessary and safety-threatening situation. You can read about the situation with airspace infringements (External link)in its own section.

Finnish aircraft continue to experience significantly more near-misses with drones abroad than in Finland. Last year, 11 such incidents were reported, which was slightly fewer than the previous year, but still above the long-term average.

The majority of foreign incidents were reported from the UK, particularly around London. There were also individual reports from countries around the world. Three of these incidents were classified as serious incidents. All of the serious incidents occurred around London or Manchester, when a drone was flown without permission close to the approach path of a Finnish aircraft. London has been a "hot spot" for unauthorised drone activity in recent years.

Air traffic control

A total of 20 air traffic control-induced aircraft separation minima infringements (excluding wake turbulence or aircraft-to-airspace separation minima infringements) were reported in 2024. This was slightly above the average for 2014–2023.

In addition, there were a few reported incidents where aircraft, typically flying under visual flight rules, ended up too close to each other. In these cases, traffic reports from air traffic control were not always sufficient to prevent the situations.

The majority of the separation minima infringements occurred in the Helsinki-Vantaa Airport area, followed by Jyväskylä and Tampere-Pirkkala. However, the infringements were mostly minor and did not cause any significant consequences.

Near misses typically occurred during the approach phase of a flight. These situations were caused by a variety of factors, including weather conditions, errors in air traffic control, or flight crew actions that were not according to the clearance.

Types of incidents contributing to near misses

Airspace infringements  (External link)are described in more detail in their own section In addition, other events to be monitored that may contribute to near misses include, for example, level busts, lateral deviations from the route, transponder failures, and incorrect responses to TCAS commands.

In 2024, 47 level busts were reported in Finland, which was largely in line with the average of previous years. Most of the incidents occurred in military aviation, where the numbers vary greatly from year to year. Last year, the number of reports increased from the previous year. Typically, military aircraft or aircraft formations did not follow the clearance altitude when entering or leaving training areas.

In civil aviation, level busts were reported on average at the same level as in previous years (approximately 28). These cases mainly concerned commercial air transport or general aviation situations where clearance altitude was not adhered to during the en-route phase of the flight.

Abroad, 36 clearance altitude violations were reported for Finnish aircraft, which was clearly above the long-term average. The incidents were widely distributed across different European regions, and the reasons varied. The most common factors were, for example, a misheard call sign, a congested radio frequency, a misunderstood clearance or an incorrectly set altitude in the aircraft's system.

138 lateral deviations from the route were reported in Finland and for Finnish aircraft, which was clearly above the average for 2014–2023. In Finland, 95 cases were reported, almost double the average. The majority of cases were recorded at Helsinki Airport airspace, and secondly in the airspace controlled by the area control center. Although deviations increased, they did not cause significant consequences.

The number of deviations began to increase, especially since May. The reasons were often typical situations, such as incorrectly setting a waypoint in the aircraft's system or not following the final approach line as reported. In addition, more exceptional situations were reported related to the effects of the war in Ukraine, such as sudden changes of direction by Russian aircraft and weather avoidance maneuvers into Finnish airspace.

In addition, there were reports of cases where an aircraft encountered GPS interference during the enroute phase of the flight, and during the approach its heading deviated from the planned one. GPS interference typically affects the aircraft's navigational capabilities, requiring it to use backup navigation systems or request navigation assistance from air traffic control. Traficom has published more detailed information on the subject on the Satellite navigation interference in Finland  (External link)website.

No significant increase in route deviations was observed abroad, and reports remained at the level of previous years. Individual cases due to GPS interference were reported, but the majority of deviations were due to other reasons.

There was no significant change in reports of transponder failures or incorrect transponder code settings last year compared to previous years. The numbers remained at the long-term average.

Radio communication failures were reported more than average, and the number also increased from the previous year, both in Finland and abroad. Typical situations included interference noises on radio frequencies, problems in contacting air traffic control, or selecting a wrong radio frequency. Several cases were reported in Finland in which a general or recreational aviation aircraft did not establish proper radio contact in airspace that required such. If air traffic control clearance is not obtained before flying into controlled airspace, this is an airspace infringement.

27 reports of TCAS avoidance commands were received. This was slightly above the long-term average. Most of the incidents occurred abroad. They often involved situations where an aircraft's large climb or descent rate activated another aircraft's TCAS system, but the required separation minimum was maintained.

There was one report of incorrect reaction to a TCAS resolution advisory. Such reports are very rare. In this case, the pilot quickly realized his mistake and corrected the situation without any safety implications.