A fatal midair collision between two firefighting helicopters near Psatha in western Attica, Greece, has prompted an extensive investigation into possible failures involving visibility, aircraft separation and operational coordination. The two leased Bell helicopters collided on Sunday, Aug. 2, while battling a large wildfire across the Attica-Boeotia region.

The collision claimed the lives of a Greek aerial operations coordinator and a Danish pilot. The two crew members aboard the other helicopter—a Greek coordinator and a British pilot—survived and were taken to the 251 General Air Force Hospital. Authorities later released video footage showing the helicopters in the moments leading up to the crash. Aviation experts have identified several possible contributing factors, but they stress that the footage alone is not sufficient to determine the cause.

Authorities investigate collision between two firefighting helicopters in Greece

The Hellenic Fire Service confirmed that the Bell helicopters collided during aerial firefighting operations near Psatha. Search and rescue teams immediately deployed to the area and recovered all four crew members. Fire Service Chief Lieutenant General Theodoros Vagias coordinated the emergency response at the crash site.

Both helicopters had departed from Elefsina Air Base before joining the firefighting mission. The competent authorities will now reconstruct the aircrafts’ flight paths, determine the role assigned to each crew and examine the instructions issued before the collision. Investigators are also expected to review flight records, radio communications, operational plans, witness testimony and all available video footage.

Experts examine the helicopters’ assigned roles

Pilot and aviation expert Pantelis Fragkoulis described the collision as a “tragic mistake” but warned against drawing conclusions before investigators establish what each helicopter was doing. According to Fragkoulis, one important question concerns whether the second helicopter had a firefighting or aerial coordination role.

Had it been serving as a coordination aircraft, he said, it should not normally have operated at the same altitude as helicopters carrying out repeated water drops and sharp maneuvers above the active fire. However, the available footage does not show the crews’ assignments or the instructions they had received.

Investigators must therefore determine whether both helicopters were conducting firefighting runs, whether one was coordinating the operation and how each aircraft entered the same section of airspace.

Speed and a last-second turn may have contributed

Retired Hellenic Air Force Lieutenant General Vasilis Vrettos said the video appears to show one helicopter traveling considerably faster than the other. He suggested that the pilot of the faster aircraft may have lost visual contact because the other helicopter was flying below the pilot’s normal field of view.

The lower helicopter also appears to turn shortly before impact. According to Vrettos, that maneuver may have further reduced the time and distance available for either pilot to react. Although helicopter collisions remain rare, Vrettos noted that aerial firefighting places crews under intense pressure. Pilots often fly at low altitude through smoke, turbulence and rapidly changing air currents while monitoring radio traffic and nearby aircraft.

“The commanders are responsible for ensuring crews fly under safe conditions,” he said. Vrettos added that investigators must consider possible coordination failures, inadequate safety procedures, human error and environmental or mechanical factors.

Loss of safe separation emerges as a key theory

Aviation accident expert Faithon Karaiosifidis said his initial analysis indicates that the two helicopters may not have maintained sufficient separation. The trailing helicopter may have lost sight of the aircraft ahead after completing a turn, he said. Its rotor blades then appear to have struck the first helicopter’s rotor system, causing catastrophic damage.

Karaiosifidis explained that severe damage to a helicopter’s rotor system and transmission removes the lift and control required to remain airborne, leaving almost no chance of recovery. Investigators will also consider whether strong upward or downward air currents affected either helicopter. Large wildfires can generate powerful and unpredictable air movement, particularly when extreme heat interacts with surrounding terrain.

Nevertheless, Karaiosifidis considers a temporary loss of visual contact one of the most plausible scenarios visible in the footage. The lead helicopter may have entered a blind spot below the trailing pilot’s field of vision. Once the pilot detected the danger, too little time or space may have remained for an effective evasive maneuver.

Bell helicopter blind spots come under scrutiny

Aeronautical engineer and aviation expert Kostas Lakafosis described the accident as unprecedented in Greece. Speaking to a Greek broadcaster, he said the video suggests that neither pilot recognized the other helicopter’s position before impact. Lakafosis explained that the Bell helicopters involved have significant blind spots because their cockpits do not feature fully transparent bubble-style canopies. The design restricts visibility in certain directions, particularly above and below the aircraft.

He also said the helicopters did not appear to be flying in a standard formation. In conventional formation flight, the trailing aircraft remains slightly behind and below the lead helicopter, allowing the pilot to maintain continuous visual contact. In this case, Lakafosis believes the helicopters converged on the same flight path from different directions. Neither pilot appeared to adjust position in response to the other aircraft before the collision.

At the moment of impact, one helicopter appeared to be directly above the other. The upper pilot would have struggled to see an aircraft beneath the fuselage, while the lower crew would have had limited visibility of an aircraft approaching from above. That relative position could explain why neither pilot began an evasive maneuver early enough to prevent the crash.

Radio communications and third crew could provide answers

Lakafosis said testimony from the crew of a third helicopter operating over the fire could prove critical. A Fire Brigade coordination helicopter identified as FLOGA 1, a BK 117, was also taking part in the operation.

However, Lakafosis stressed that an airborne coordinator cannot continuously monitor every aircraft during a complex firefighting mission. Helicopters may approach from different directions, fly at different altitudes or temporarily disappear behind smoke, terrain and other aircraft.

Radio communications among FLOGA 1, the two Bell helicopters and ground coordinators may help investigators determine whether the pilots knew each other’s positions. The recordings could also show whether crews clearly understood their instructions and whether anyone issued a warning before impact.

Investigators will examine whether the operation used designated water-pickup, approach, drop and exit routes, as well as whether each crew received adequate information about nearby aircraft.

Single-pilot operations aboard both firefighting helicopters in Greece raise safety questions

The Bell helicopters involved in the collision are certified for single-pilot operations. Although regulations permit that configuration, Lakafosis said it may not offer the highest level of safety during demanding aerial firefighting missions. Larger helicopters with multi-person flight crews benefit from additional personnel who can monitor nearby traffic, assist with navigation and strengthen situational awareness.

In the Bell helicopters, the second occupant primarily assists with radio communications and mission-related tasks rather than acting as a second pilot or dedicated flight coordinator. Investigators may therefore examine whether cockpit workload, restricted visibility and communication demands affected the pilots’ ability to detect the developing conflict. The released video offers only a partial view of the accident. A definitive explanation will require a detailed reconstruction of the helicopters’ movements, crew assignments, communications and operating conditions during the final moments before the collision.

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