French helicopter collision due to poor communication, report finds

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Thirteen French soldiers died in the collision of two helicopters in Mali on November 25, 2019. The two aircraft were taking part in combat operations against jihadists. The final report found that the accident was mainly due to poor communication among the different flight crews.

What happened?

On November 22, 2019, French soldiers participating in the Barkhane mission began the pursuit of a group of jihadist insurgents, who were “organized and equipped with a pickup truck and several motorcycles”. The insurgents were involved in a series of attacks killing over a hundred Malian soldiers in the previous weeks. The Liptako, a region in central-eastern Mali bordering Niger and Burkina, is known to host members of the Islamic State in the Great Sahara, a group that swore allegiance to ISIS. 

After a two-day chase, the members of the Commando Parachute Group (GCP) caught up with the jihadists and started exchanging fire. Facing difficult terrain that forced them to stop their pursuit, the French soldiers requested aerial support.

A patrol of three helicopters of the French Army Light Aviation was sent from Menaka, 40 miles east of the combat zone. It was composed of two Gazelle attack helicopters and one Cougar transport helicopter with a mission leader and a squad of mountain commandos on board. 

Additionally, two Airbus Tiger attack helicopters of the 5th Combat Helicopter Regiment were also scrambled from Gao, approximately 110 miles west of the combat zone.

The aircraft were sent on a low-altitude reconnaissance mission “in combat conditions and very demanding operational conditions”. It was “a moonless night, in total darkness,” described the French Minister of Armed Forces Florence Parly at the time. 

The flight group of three helicopters arrived first. As the two Gazelles started engaging the insurgents, the Cougar climbed up to 3,200 feet in order to observe the terrain using its optronics system. 

When the Tigers arrived at the combat zone, the leader asked for the position of the other aircraft already engaged. After the Cougar gave its altitude and its position, north-east of the zone, the Tiger leader reduced its own altitude to 2,800 feet to avoid a collision. The patrol then split in two; the leader remained to hover above the zone while the wingman flew south to engage the jihadists. 

In the next minutes, the Cougar came back above the combat zone at around 3,200 feet, without announcing its change of position. At the same moment, the Tiger leader climbed up to around 3,300 feet, but only warned its wingman.

The Tiger leader and the Cougar, then both flying in circles around the combat zone, came close to each other at barely 900 feet of separation, without seeing one another. Two minutes later, as the Tiger leader was descending, the two aircraft collided. None of the 13 occupants (two Tiger pilots, five crew members of the Cougar helicopter, and six soldiers) survived. 

An “erroneous situational awareness”

On January 30, 2021, the French Accident Investigation Bureau for State Aviation Safety (BEA-É) released its final report on the accident. “The collision could not be avoided because the crews did not detect the presence of the other aircraft,” states the report. “Their respective awareness of the situation was wrong. The causes relate exclusively to organizational and human factors.”

  • All aircraft were out of any radar coverage and were employing a “see and avoid” method to prevent collisions. Unlike their civilian equivalents, military helicopters do not possess anti-collision devices, as they have to operate in tighter formations. Thus, the crew had to rely solely on their own perception. 
  • The ambient darkness forced pilots to employ night vision goggles, but the presence of a fire on the ground complicates their use. Additionally, in combat conditions, position and anti-collision lights are turned off. 
  • Finally, the TACAN (TACtical Air Navigation) navigation system, which gives a distance between two aircraft, was neglected by the Cougar’s crew, which was too “focused on the mission and the objective.” Those elements all contributed to the failure of the pilots to detect the impending collision.

But what the report highlights the most is the failure of aircraft to communicate with one another.

  • The investigators found that no common safety briefing for all crew members, whether prior to takeoff or while flying to zone, was carried out.
  • During the mission, several communication channels were used, rendering the messages unclear when two people were talking simultaneously and preventing all aircraft from being fully aware of the ongoing operations. 
  • The vocabulary used during the communication was also unclear. At one point, the Tiger leader was using “we” (‘on’ in French) to describe their movement, leaving doubt as to whether it referred to one aircraft or the patrol of two combat helicopters. 
  • The mission leader on board the Cougar and the leader of the Tiger patrol were subject to an “increased mental load” due to a multiplicity of missions. In particular, the report found out that the “Cougar crew members took on an image intelligence mission” despite having no training in Crew Resource Management while operating a thermal camera.

Thus, the report recommends that the French Army define clear rules and procedures to ensure aircraft collision avoidance and to remind these rules to its crews during the briefing before each mission. As for the technical aspect, the BEA-É asked the authorities to study “the possibility of equipping non-compatible aircraft with mutually compatible collision avoidance systems.” 

Overall, while the investigation found the main cause of the accident to be the “human factor”, the report does not put the blame on the crew members. Instead, the BEA-E points at a “cultural” problem within the French Army Light Aviation and its “tendency to favor the monitoring of a tactical surface situation to the detriment of air risk management.” 

To this date, the crash remains the deadliest combat operation for the French military since it deployed in Mali to fight back Islamic insurgents in 2013. In total, 55 French military personnel were killed in Operation Barkhane.


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