A warning of smoke, a sudden engine change and a devastating loss of control: the preliminary findings reveal how quickly the final flight unfolded.
It began as another routine skydiving flight from Nancy-Essey Airport in northeastern France. The Pilatus PC-6 had already completed several trips that day, carrying instructors and passengers preparing to experience a parachute jump. The weather appeared favorable, the aircraft was within its permitted weight, and the pilot was highly experienced.
Then, during the take-off, someone inside the cabin noticed something alarming.
“There’s smoke!”
A second instructor soon raised the same concern, pointing toward the floor near the front-right section of the aircraft. The people on board had only moments to react. The side door was partially opened in an attempt to ventilate the cabin. Shortly afterward, the engine parameters changed, the aircraft’s nose rose, and the stall warning sounded.
Within seconds, the flight ended in disaster.
All 11 people aboard were killed when the aircraft crashed near Tomblaine on June 28, 2026. The victims included the pilot, five skydiving instructors and five people preparing for tandem parachute jumps. The tragedy shocked the local community and prompted a major investigation into what happened during the aircraft’s final moments.
The preliminary report published by France’s Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) has since provided a much clearer account of the sequence inside the aircraft. It describes the smoke warnings, the decision to open the side door slightly, a sudden reduction in engine gas-generator speed, changing propeller behavior, and a series of stall warnings before the aircraft lost control.
Yet the report does not provide a complete answer to the most important question: what caused the smoke, and what exactly led to the loss of control?
The pilot had approximately 10,500 flight hours. The aircraft’s take-off weight was below its maximum permitted limit. Weather conditions were favorable. Those details make the sequence especially difficult to understand at first glance.
But aviation accidents rarely have one simple explanation. A warning inside the cabin, a mechanical problem, a change in aircraft performance, and the actions taken under pressure may all need to be examined together.
To understand the tragedy, we must go back to the beginning of that flight—and then follow the evidence through the moments that changed everything.
Chapter 1: The Final Take-Off From Nancy-Essey Airport
The aircraft involved was a Pilatus PC-6/B2-H4 Turbo Porter registered as D-FIPS. It was being used for parachuting operations by Tandemotion Parachutisme, a company that organized commercial tandem skydiving experiences.
The PC-6 is a single-engine turboprop aircraft designed for operations that require strong short-field performance and the ability to carry people or equipment into demanding environments. Its high-wing configuration, fixed landing gear, and large cabin make it particularly suitable for parachuting activities.
On June 28, 2026, the aircraft was scheduled to carry out another local flight from Nancy-Essey Airport. The plan was familiar: take off, climb to the required altitude, allow the parachutists to jump, and return to the airfield for the next group.
The flight was not a long-distance journey. It was a specialized operation that depended on repeated take-offs and landings, with the aircraft returning to the same airport after each jump.
That routine is important because the aircraft had already completed several rotations before the fatal flight.
A sixth rotation of the day
According to the BEA preliminary report, the pilot lined up on runway 21 from taxiway B2 and prepared for the sixth rotation of the day. Ten parachutists were on board.
The aircraft had completed an earlier block of three rotations. The accident occurred during the third flight of the second block, meaning the aircraft had already made five trips before beginning the fatal one.
This was not an unusual kind of schedule for a parachuting operation. The aircraft had been used for repeated flights, and the operation was planned around groups of passengers and instructors.
The previous day, the pilot had completed 15 rotations with the same aircraft for Tandemotion Parachutisme. The company had planned another 15 rotations on June 28, although the schedule included a break during the hottest part of the afternoon because of the forecast high temperatures.
The fact that the aircraft had completed several flights earlier in the day does not, by itself, establish that fatigue or accumulated mechanical stress played a role. It does, however, make the maintenance history, operating schedule, fuel records, and technical condition of the aircraft important parts of the investigation.
The people on board
There were 11 people aboard: the pilot and ten parachutists.
The ten passengers included five instructors and five people who had come to experience tandem skydiving. Reports identified the five novice participants as nursing students. The flight was intended to provide them with a parachuting experience, not to transport them to another destination.
For those on board, the journey was supposed to be a short and exciting part of a planned activity. The passengers had prepared for a jump, while the instructors were responsible for helping ensure that the operation was carried out safely.
The aircraft’s cabin was arranged for parachuting. The occupants wore equipment associated with the activity, and the instructors were positioned in different parts of the cabin.
The preliminary report specifically refers to one instructor seated toward the rear and another seated in the middle. Their positions would become important because both independently reported seeing smoke in the forward-right area of the cabin.
The pilot’s experience
The pilot was 44 years old and held a commercial pilot licence. The BEA report recorded approximately 10,500 total flight hours, including around 4,000 hours on the Pilatus PC-6.
He had obtained his PC-6 qualification in 2015 and had maintained the relevant qualifications over the years. The report also states that he was employed by the company that owned the aircraft and flew the D-FIPS regularly.
Those details are important because they show that the aircraft was not being operated by an inexperienced person unfamiliar with the type.
However, experience cannot prevent every emergency. Even a highly experienced pilot may face a situation in which several warning signs appear within seconds, leaving little time to identify the cause and select the safest response.
A pilot’s total flight hours are only one part of an investigation. Investigators must also examine recent experience, time on the aircraft type, training, operating procedures, medical fitness, and the specific conditions of the flight.
The BEA report noted that the pilot’s logbook recorded a previous flight on June 8 and a previous PC-6 flight on May 10. It also cautioned that the logbook may not have been fully up to date. Witness accounts indicated that he had around 4,000 hours of experience on the PC-6 and had flown the aircraft regularly.
The report does not conclude that the pilot’s experience or qualifications caused the accident.
The aircraft’s weight was within the permitted limit
One early question after any aircraft accident is whether the plane was carrying too much weight or whether the distribution of passengers and equipment affected its balance.
The preliminary report addresses this issue directly.
Based on the actual weights collected during the investigation, the aircraft’s take-off mass was calculated at approximately 2,590 kilograms. The maximum permitted take-off mass was 2,800 kilograms.
That meant the aircraft was about 210 kilograms below its maximum permitted weight.
Investigators also calculated the centre of gravity at approximately 31.5 percent, taking into account the observed positions of the parachutists. This figure was within the manufacturer’s permitted range.
The report states that the aircraft’s mass and centre of gravity were within the required limits. It also says that no movement of the occupants was observed before the loss of control.
These findings are significant because they make an obvious weight or balance problem less likely as an explanation for the crash.
They do not eliminate every possible performance issue. An aircraft can be within its approved weight limits and still experience a mechanical malfunction, an engine problem, or a loss of control.
But the preliminary figures do not support the simple claim that the plane crashed because it was overloaded.
The weather on the morning of the accident
Weather conditions were another important part of the investigation.
At approximately 11 a.m., the airport’s weather observation recorded a wind from 260 degrees at around eight knots, with visibility and cloud conditions reported as CAVOK. The temperature was approximately 33 degrees Celsius, with a dew point of 18 degrees.
The meteorological data also showed that temperatures close to the ground were higher than the temperature measured in the sheltered observation area. At 10:59 a.m., the recorded temperature 10 centimetres above the ground was approximately 41.1 degrees Celsius.
The weather was therefore hot, even though visibility and the general flying conditions were favorable.
High temperatures can affect aircraft performance because warm air is less dense than cooler air. Lower air density can reduce the amount of oxygen available to an engine and can affect the aerodynamic performance of an aircraft.
That does not mean the heat caused this crash. The BEA report does not establish such a conclusion. It simply provides the environmental measurements that investigators must consider when reconstructing the aircraft’s performance.
The aircraft’s calculated take-off distances were also compared with the actual flight data. The report found that the theoretical distances were consistent with the distances recorded during the accident flight.
At first glance, the available information suggested that the aircraft had begun the take-off within normal operating conditions.
Then came the first warning from inside the cabin.
Chapter 2: “There’s Smoke!” — The First Warning Before the Crash
The most striking detail in the preliminary report is the moment when an instructor noticed something unusual inside the aircraft.
During the take-off rotation, as the aircraft was accelerating and preparing to leave the runway, an instructor seated toward the rear shouted that there was smoke.
He pointed toward the front-right area of the cabin.
The pilot did not appear to hear the warning and continued the take-off.
A second instructor, seated in the middle of the aircraft, then also shouted that there was smoke. He pointed toward the same general area, near the floor.
The two instructors agreed to partially open the side door to ventilate the cabin.
This sequence is central to the investigation because it establishes that more than one person reported a possible smoke problem before the aircraft lost control.
It also creates a difficult question: if smoke was present, why could investigators not see it in the available recordings?
Two separate warnings
The fact that two instructors independently reported smoke is important.
A single observation can sometimes be mistaken. Light reflecting from a surface, dust, vapor, or an unusual smell may be interpreted incorrectly in a stressful environment.
But when two people point toward the same general area and report the same problem, investigators must take the reports seriously.
The instructors were familiar with parachuting operations and the aircraft environment. Their warning was not a casual comment. It was an observation made during a critical stage of flight.
The BEA report records their words and actions but does not determine what substance or condition they were seeing.
The distinction is crucial. The preliminary report establishes that smoke was reported. It does not establish that investigators found visible smoke in the cabin or identified its source.
Why the side door was partially opened
The instructors agreed to open the side door slightly to ventilate the cabin.
From their perspective, the action was an attempt to improve the conditions inside the aircraft. If smoke was present, opening the door could help remove it or reduce its concentration.
However, opening an aircraft door during take-off or flight is not an ordinary action. The effect depends on the aircraft’s design, the door configuration, airflow, and the phase of flight.
The BEA report describes the decision but does not state that opening the door caused the accident.
It would therefore be inaccurate to claim that the instructors’ action was responsible for the crash. The investigators must establish the sequence of events and assess whether the door’s position had any measurable effect on the aircraft’s behavior.
This is one of the details that makes the preliminary findings so important: they reveal what happened, but they do not yet provide a complete explanation of why it happened.
The pilot may not have heard the first warning
According to the BEA, the pilot did not appear to hear the first instructor’s shout.
That wording should be treated carefully. It does not necessarily mean the pilot ignored the warning. The report describes what investigators could infer from the available evidence.
During take-off, pilots are dealing with engine power, aircraft speed, runway alignment, control inputs, and the transition from ground movement to flight. The cockpit environment can also be noisy.
A warning from the rear of a cabin may be difficult to hear, particularly if the aircraft is accelerating and the engine is operating at high power.
The second warning came from another part of the cabin, but the report does not provide evidence that the pilot had enough time to understand the situation and respond before the aircraft’s performance began to change.
The available sequence indicates that the aircraft continued its take-off and then experienced a significant reduction in engine gas-generator speed.
The engine parameters suddenly changed
Shortly after the smoke warnings, the gas-generator speed, identified in the report as Ng, decreased by approximately 10 percent.
At around the same time, the propeller speed, identified as Np, briefly fluctuated before returning to its nominal value of 2,000 revolutions per minute.
The change in Ng was particularly significant because the report states that the reduction had not occurred during the five preceding take-offs that investigators compared with the accident flight.
The BEA also states that the Ng value remained stable after the reduction until the end of the available recording.
At the time of the preliminary report, investigators had not determined whether the decrease was commanded or occurred because of a malfunction.
That distinction is important.
A commanded reduction would mean that the engine setting changed as a result of an input or control action. A reduction that was not commanded could indicate a mechanical, fuel-related, or other technical problem.
The preliminary report does not establish which explanation applies.
Understanding Ng and Np
The two engine parameters may sound highly technical, but they help explain why investigators are examining the aircraft’s engine so closely.
Ng refers to the speed of the gas generator within the turboprop engine. The gas generator is a central part of the engine’s operation, producing the hot gas flow that drives the turbine.
Np refers to the rotational speed of the propeller.
In a turboprop aircraft, the engine and propeller work together to produce thrust. A change in gas-generator speed may affect the engine’s ability to deliver power, while propeller speed provides another important indication of how the propulsion system is operating.
A brief fluctuation in propeller speed does not automatically identify the cause of a malfunction. It must be considered alongside other recorded parameters, physical examinations, and the engine’s condition.
The BEA’s preliminary findings show that the propulsion system experienced an unusual change during the take-off sequence. They do not yet identify the exact failure mechanism.
Why the smoke and engine changes matter together
The timing of the smoke warnings and the engine parameter changes is one of the most important aspects of the case.
The instructors reported smoke in the front-right area of the cabin. Soon afterward, the engine’s gas-generator speed fell by approximately 10 percent.
That sequence raises the possibility that the two events were connected.
For example, an issue in the engine compartment or a system near the forward cabin could potentially produce both a visible or perceived smoke condition and a change in engine performance.
But this remains a line of investigation, not a confirmed explanation.
The investigators need to determine where the reported smoke originated, whether it was actually smoke, and whether the engine’s performance change was caused by the same underlying problem.
The preliminary report specifically says that the origin of the reported smoke had not been established.
The mystery of the missing smoke in the recordings
One of the most puzzling findings is that none of the examined videos showed visible smoke escaping from the aircraft.
The BEA examined five GoPro cameras carried by the instructors. The recordings began during taxiing and continued through the take-off sequence until the loss of control. Some footage showed the cabin interior, while other sections showed the outside of the aircraft.
No visible smoke was identified in the recordings.
Investigators also obtained video from a witness on the ground, a surveillance camera, and a moving vehicle. Those recordings likewise did not show smoke coming from the aircraft.
This does not automatically prove that the instructors were mistaken.
Smoke may be difficult to see depending on its density, color, lighting, location, and the camera angle. A small amount of smoke near the floor may not be clearly visible in a recording, particularly if the camera is facing another direction.
The cameras may also have been unable to capture the precise area where the instructors pointed.
There is another possibility: the instructors may have observed something that looked like smoke but was not smoke from a fire.
The investigation must consider all of these possibilities.
The fact that no visible smoke appears in the footage is a significant finding, but it is not enough by itself to dismiss the eyewitness reports.
The last recorded moments
The aircraft’s recorded flight parameters provide another important piece of the story.
The BEA used data from a Garmin GI-275 electronic flight instrument, as well as information extracted from the GoPro recordings.
The aircraft initially accelerated and rotated in a way that was similar to the two preceding flights. The rotation occurred at approximately 60 knots.
After the reduction in Ng, the aircraft reached a maximum speed of approximately 73 knots around two seconds later. At that point, its pitch attitude was about nine degrees, and its altitude was approximately 780 feet above mean sea level.
Afterward, the recorded parameters began to diverge from those of the earlier flights.
The aircraft’s speed decreased while its nose-up attitude increased significantly. The roll initially moved toward the right and then toward the left.
The pitch angle reached approximately 19 degrees, while the left bank exceeded 20 degrees and continued to increase. The indicated airspeed had fallen to approximately 55 knots.
Control was lost shortly afterward.
Those figures describe a rapid deterioration in the aircraft’s flight condition.
They also explain why the final moments were so critical. The aircraft was still close to the ground, and the pilot had very little altitude available to recover from a developing stall.
Chapter 3: The Aircraft Loses Control — A Chain of Events in Seconds
After the engine parameters changed, the aircraft entered a sequence that ended with a loss of control.
The BEA report describes an increase in pitch attitude, three brief stall-warning activations, a left turn with a high nose-up attitude, and then a continuous stall warning. The aircraft entered an asymmetric stall and struck the ground.
These terms can be difficult for readers who are not familiar with aviation, but they describe a critical situation in which an aircraft can no longer maintain the airflow needed to produce sufficient lift.
What is an aerodynamic stall?
An aerodynamic stall occurs when the wing exceeds its critical angle of attack. In simple terms, the wing is presented to the airflow at an angle that prevents it from producing the lift required for controlled flight.
A stall is not simply an engine stopping. An aircraft can stall even when its engine is operating, because the problem concerns the airflow over the wings.
A stall can occur during different phases of flight, but a stall shortly after take-off is particularly dangerous because the aircraft has limited altitude and little time to recover.
The pilot may need to lower the nose, reduce the angle of attack, manage the aircraft’s bank, and regain sufficient airspeed. The available recovery space depends heavily on altitude, aircraft configuration, and the nature of the stall.
In the Tomblaine accident, the aircraft was still climbing at low altitude when its speed began to decrease and its pitch angle increased.
Why the warning sounded three times
The preliminary report states that the stall warning activated briefly on three occasions before becoming continuous.
A stall-warning system is designed to alert the pilot when the aircraft approaches a condition in which the wings may no longer produce sufficient lift.
The warning is not itself the stall. It is an indication that the aircraft is approaching a dangerous aerodynamic condition.
The fact that the warning sounded repeatedly before becoming continuous suggests that the aircraft was moving into an increasingly critical flight state.
The recorded data show that the aircraft’s pitch increased while its speed decreased. These changes are consistent with a developing stall situation.
However, the report does not establish why the aircraft entered that condition. Investigators still need to determine how the engine change, the pilot’s control inputs, the aircraft’s configuration, and any possible technical malfunction interacted.
The left turn and asymmetric stall
The BEA states that the pilot turned left while the aircraft had a high pitch attitude. The stall warning then sounded continuously, and the aircraft entered an asymmetric stall.
An asymmetric stall is a particularly dangerous condition because the two wings do not lose lift in exactly the same way or at the same moment.
One wing may lose lift more severely, causing the aircraft to roll or yaw unexpectedly. The resulting movement can be difficult to control, especially when the aircraft is already close to the ground.
The preliminary report records that the aircraft’s roll moved first toward the right and then toward the left, with the left bank increasing beyond 20 degrees.
It is important not to interpret this as proof that one particular control input caused the accident. The data describe the aircraft’s movement, but the final explanation requires a detailed reconstruction of the flight and the technical condition of the aircraft.
The impact near the runway
The aircraft struck the ground approximately 200 metres beyond the end of runway 21 and about 150 metres to the left of the runway centreline, according to the BEA report.
The wreckage was found near small bushes and streetlights. Investigators did not observe evidence that the aircraft had collided with those objects before reaching the ground.
The impact trajectory was close to vertical, with a steep nose-down attitude and a left bank.
The wreckage remained largely grouped together, and the flight-control systems were found to have continuity at the time of impact. The aircraft was subsequently transported for further technical examination.
The location of the crash was particularly concerning because it was close to a residential area.
The aircraft came down near homes and public routes. Early reports described how narrowly the accident avoided causing additional casualties on the ground. The 11 people aboard were killed, but no further deaths were reported among residents or passers-by.
A tragedy that could have been even worse
The aircraft’s final trajectory brought it down close to a populated area. That fact added another dimension to the tragedy.
A crash involving a small aircraft can endanger not only those aboard but also people living or working nearby. A falling aircraft may strike buildings, vehicles, roads, or public spaces.
In Tomblaine, the crash site was close to residential buildings and a cycle route. The fact that the aircraft did not strike a home or cause additional casualties on the ground was a significant part of the early public discussion.
For the local community, however, the event was still devastating. Emergency services had to secure the site, deal with the wreckage, and support the families and witnesses affected by the accident.
The investigation would have to examine the crash itself while also reconstructing the events that began inside the aircraft during take-off.
Chapter 4: The Technical Clues Found in the Wreckage
The preliminary report does not simply describe the final flight. It also documents the examination of the aircraft and its systems.
This part of the investigation is especially important because some possible explanations can be tested through physical evidence.
Investigators examined the wreckage, dismantled components, inspected systems, and looked for traces that might indicate smoke, overheating, or mechanical failure.
Some findings helped narrow the investigation. Others raised new questions.
The aircraft’s maintenance history
The aircraft was a Pilatus PC-6/B2-H4 fitted with a Pratt & Whitney PT6A-27 turboprop engine and a three-blade Hartzell constant-speed propeller.
At the time of the accident, the airframe had accumulated approximately 12,560 flight hours and 22,640 cycles. The engine had recorded approximately 7,540 operating hours, including around 3,785 hours since its last major overhaul.
The last scheduled 100-hour airframe and engine inspection had been completed in April 2026 at a maintenance facility in Switzerland. The aircraft’s certificate of airworthiness was valid until July 31, 2026.
These details are relevant because investigators must determine whether the aircraft had any known maintenance issues or defects before the accident.
A valid certificate of airworthiness does not guarantee that a mechanical failure cannot occur. It indicates that the aircraft met the applicable requirements at the time of certification, but a sudden fault may still develop.
The BEA’s examination therefore looked beyond the paperwork and focused on the physical condition of the components.
The flaps and flight-control systems
Investigators examined the aircraft’s flaps and control systems.
The flaps were present on both wings, and the control linkage was continuous. No anomaly that could have contributed to the accident was identified in the preliminary examination.
Measurements indicated that the flaps were extended symmetrically in an intermediate position. The exact position was still being determined.
The investigators also examined the aircraft’s trim systems.
The PC-6 uses a system that allows the horizontal stabilizer and other trim surfaces to be adjusted. These systems help the pilot manage the aircraft’s attitude and control forces.
The electric actuator controlling the horizontal stabilizer was found to be installed normally. It showed no anomaly during dismantling or tomography examination. Its recovered position was consistent with the manufacturer’s recommended take-off configuration.
The rudder and aileron trim systems were also examined. The preliminary report did not identify an abnormality in their installation or examination, and their measured positions were consistent with the recommended take-off settings.
These findings are significant because investigators were checking whether an abnormal trim setting or a failure in the control system might have contributed to the aircraft’s unusual pitch and roll.
At the preliminary stage, the examined trim systems did not provide evidence of such a problem.
Three warning lights found on the aircraft
One of the most important technical discoveries involved the aircraft’s warning panel.
The BEA examined the small filament lamps inside the warning indicators using X-ray imaging. The investigators found that three indicators had filaments showing deformation patterns that were consistent with the lamps being illuminated at the time of impact.
The three indicators were:
PROP LOW P: an indication that the propeller had reached its minimum pitch in flight.
CHIP: a warning that metal particles had been detected in the turboprop engine oil.
F-FILTER: an alert indicating that the fuel filter was clogged.
These findings are potentially important because they involve the propeller, engine lubrication, and fuel supply.
However, the report also makes an essential qualification: investigators had not yet determined whether the indicators illuminated before or after the loss of control.
That timing matters enormously.
If a warning appeared before the aircraft began losing control, it might provide evidence of a developing technical problem. If it appeared only after the aircraft had already entered an abnormal flight condition or during the impact sequence, its significance could be different.
The warning lights therefore represent clues, not a final explanation.
What the CHIP warning could mean
The CHIP warning is associated with the detection of metal particles in the engine oil.
Metal particles may be produced by wear or damage inside mechanical components. In an engine, the presence of metal contamination can indicate that parts are rubbing, deteriorating, or failing.
But the indicator alone cannot identify which component was involved, how serious the issue was, or when the contamination began.
Investigators would need to examine the oil system, engine components, filters, and any recovered material. They would also need to compare physical findings with the recorded engine data.
The preliminary report does not conclude that the CHIP warning caused the accident.
What the F-FILTER alert could mean
The F-FILTER alert indicates a clogged fuel filter.
A fuel filter is designed to prevent contamination from reaching the engine’s fuel system. If a filter becomes obstructed, the flow of fuel may be affected.
A fuel-flow problem could potentially influence engine performance. That makes the warning relevant when investigators are examining the sudden reduction in Ng.
But the presence of the warning lamp does not prove that the fuel filter caused the reduction in engine speed.
The BEA was still examining the fuel system and awaiting laboratory analysis of a fuel sample collected from the aircraft.
The report also notes that the fuel supplier had arranged independent analyses of samples from the airport’s tanker and storage tank. Those analyses did not reveal an abnormality.
The investigators therefore had several separate questions to answer: whether the aircraft’s fuel system was functioning properly, whether a filter restriction occurred, and whether any such problem could explain the engine’s recorded behavior.
The PROP LOW P warning
The PROP LOW P warning indicates that the propeller has reached a minimum pitch in flight.
The propeller’s pitch determines the angle of its blades as they move through the air. A variable-pitch propeller adjusts this angle to help the engine operate efficiently under different flight conditions.
An abnormal indication involving propeller pitch could be relevant to a sudden change in aircraft performance.
However, the preliminary report does not establish when the warning appeared or what caused it.
It is therefore too early to conclude that a propeller malfunction was responsible for the crash.
The fuel system examination
The aircraft’s fuel system had been heavily damaged in the crash, but investigators were able to reconstruct parts of it for examination.
Fuel was found in the system during dismantling. The left fuel tank provided a sample for laboratory testing, while the right tank had been ruptured and contained only a very small amount of remaining fuel.
The aircraft had received approximately 200 litres of fuel after the first block of three rotations, two flights before the accident flight. The BEA estimated that around 200 litres were present at take-off on the fatal flight.
These details are important because the investigation must consider whether a fuel-supply problem could explain the reduction in engine performance.
The report does not identify fuel contamination as the cause. The independent tests of fuel from the airport supply did not reveal an abnormality, while further analysis of the aircraft’s own fuel system was continuing.
The search for the source of smoke
The investigators also carried out a systematic search for physical evidence that smoke had been present inside the aircraft.
They examined the wreckage for soot, unusual heating, damage to insulation, and other signs that might indicate a fire or overheating.
The electrical system was separated from the aircraft structure and examined. The BEA did not identify signs of overheating, damaged insulation, or another anomaly that could have generated smoke.
The air-conditioning system was also removed for examination. Investigators did not find areas of overheating or soot deposits that would confirm smoke in that system.
These findings are important because they make some possible explanations less obvious.
But the absence of soot or visible smoke in the examined material does not automatically explain why two instructors reported seeing smoke.
The investigators still need to determine whether the reported phenomenon came from a system that left little physical evidence, whether it was a visual misinterpretation, or whether another explanation is possible.
Flames seen after the impact
A witness who was driving nearby saw the aircraft take off and then lose control.
After the crash, the witness immediately went to the site and noticed flames near the front-left section of the aircraft, approximately 30 to 40 centimetres behind the propeller.
The witness used a dry-powder extinguisher carried in the vehicle and quickly extinguished the flames. Approximately half of a two-kilogram extinguisher was used.
The BEA stated that further examinations were required to determine whether this fire was a consequence of the impact or whether it had another origin.
That distinction is crucial.
A fire after impact does not prove that a fire was present before impact. The collision could have damaged fuel or other systems and created a fire at the scene.
On the other hand, if investigators can establish that a fire existed before the crash, it could help explain the smoke warnings and the emergency sequence.
The available preliminary findings do not settle that question.
Chapter 5: What Investigators Still Need to Discover
The preliminary report has reconstructed the flight in considerable detail, but it is not the final investigation report.
That distinction is essential. The document was published to provide an initial account of the evidence collected so far, not to assign blame or announce a definitive cause.
The BEA’s stated purpose is to improve aviation safety. Its investigation is intended to establish the circumstances of the accident and identify lessons that may help prevent similar events, rather than determine legal responsibility.
Several major areas of work remained open when the preliminary report was published.
The engine must be examined in detail
The turboprop engine was one of the most important subjects for further investigation.
The BEA planned to examine it at Pratt & Whitney’s facilities in Canada, with the French investigators present.
This examination could help determine whether the engine experienced an internal mechanical problem, whether a component failed, and whether the observed reduction in gas-generator speed was associated with a specific technical defect.
The investigators will need to compare the physical condition of the engine with the recorded flight parameters.
For example, if a mechanical failure is identified, they will need to determine whether it could explain the timing and magnitude of the Ng reduction. They will also need to assess whether it could have generated smoke or another visible sign inside the cabin.
A finding involving the engine could provide an important link between the first warnings and the aircraft’s deteriorating performance.
But until those examinations are complete, it would be premature to identify a specific engine component as the cause.
The fuel system remains an important line of investigation
The fuel system is another area that requires careful examination.
The preliminary report describes the aircraft’s fuel configuration, the amount of fuel on board, the fuel added between groups of flights, and the physical condition of the recovered components.
Investigators also found that the warning panel likely showed an F-FILTER alert at impact, although its activation time remains uncertain.
The fuel sample collected from the aircraft must be analyzed, and the reconstructed fuel system must be examined to determine whether a restriction, leak, or other abnormality could have affected engine operation.
The fact that independent samples from the airport’s fuel supply did not show an abnormality is useful, but it does not eliminate every possible problem within the aircraft’s own fuel system.
What caused the smoke warning?
Perhaps the most difficult unanswered question is still the one that began the emergency.
Two instructors reported smoke in the forward-right area of the cabin. Yet the five GoPro recordings and the available external videos did not show visible smoke.
The electrical and air-conditioning examinations also did not reveal clear signs of overheating or soot.
This leaves several possibilities open.
The instructors may have seen a small amount of smoke that the cameras could not capture. They may have noticed vapor, dust, or another visual phenomenon that resembled smoke. Alternatively, an issue may have occurred in a part of the aircraft that did not leave obvious traces in the recovered components.
The investigators must determine which possibility best fits the evidence.
They must also establish whether the reported smoke and the reduction in engine speed were caused by the same event or were separate occurrences.
That connection could be essential to understanding the entire accident sequence.
The meaning of the warning lights
The three warning indicators—PROP LOW P, CHIP, and F-FILTER—could provide additional information about the condition of the aircraft.
However, the preliminary report does not establish whether they illuminated before or after the loss of control.
Their timing must be reconstructed through the examination of the lamp filaments, recorded data, and other evidence.
If one or more warnings appeared before the aircraft began losing control, they could help explain what the pilot was facing. If they appeared during or after the impact, their significance may be different.
The investigation must avoid treating every damaged or illuminated indicator as proof of a pre-existing failure.
The aircraft’s control inputs and flight data
The Garmin GI-275 recorded flight parameters that have already helped investigators reconstruct the aircraft’s movement.
The data show that the aircraft initially accelerated and rotated in a manner similar to the previous flights. The situation changed after the reduction in Ng.
The aircraft’s speed then decreased while its pitch and bank increased. The stall warning became continuous, and control was lost.
Further analysis may help establish the relationship between the engine behavior and the pilot’s control inputs.
It may also help clarify whether the aircraft’s configuration, the opening of the side door, or another factor contributed to the developing stall.
The report does not establish that opening the door caused the accident. That question requires a technical assessment rather than assumptions based on the sequence alone.
The role of the door and cabin airflow
Because the instructors partially opened the side door after reporting smoke, investigators may need to consider the door’s position and its possible effect on the aircraft.
An aircraft door can influence airflow around the cabin, particularly when opened in flight. The exact consequences depend on the aircraft’s design, the position of the door, the speed, and the surrounding aerodynamic conditions.
However, the fact that the door was opened does not establish that it caused the loss of control.
The investigators must determine how far it was opened, when the action took place, and whether it could have affected the aircraft’s performance or the occupants’ ability to respond.
This is one reason why the GoPro recordings are valuable. They provide visual information about the cabin and the actions of the people on board, although they do not show every detail of the flight.
Could the extreme heat have played a role?
The weather data show that the accident occurred on a very hot morning.
The temperature at the airport was around 33 degrees Celsius, and the temperature close to the ground was higher.
Heat can affect aircraft performance. Warm air is less dense, and reduced air density can influence engine output and wing performance.
However, the preliminary report does not identify the temperature as the cause of the accident.
Investigators must consider the actual aircraft performance, the recorded take-off parameters, and the manufacturer’s operating data. They must also determine whether the aircraft was operating within the expected performance range under the conditions that day.
The aircraft’s calculated weight and centre of gravity were within the permitted limits, and the theoretical take-off distances were consistent with the recorded performance.
These findings are important, but they do not remove the need to examine the engine and the other technical systems.
The importance of the final report
The final BEA report is expected to bring together the technical examinations, recorded data, witness accounts, and analysis of the aircraft’s systems.
It may identify a technical cause, explain a chain of contributing factors, or establish that some questions cannot be answered with certainty.
Aviation investigations are often complex because the evidence must be considered as a whole.
An engine warning may be related to a mechanical problem, but it may also be a consequence of another failure. Smoke may be reported by witnesses without appearing on video. A control movement may occur during an emergency without being the original cause of the emergency.
The investigation must establish the order of events and determine which factors were causal, contributing, or unrelated.
The preliminary report is therefore a major step forward, but it should not be mistaken for the final answer.
The Human Cost Behind the Technical Investigation
Although the technical details are essential, the Tomblaine accident was first and foremost a human tragedy.
Eleven people died in a flight that had been planned as a short parachuting experience. Five instructors and five novice participants were aboard with the pilot. Families, friends, colleagues, and members of the local community were left to deal with the sudden loss.
Some relatives were reportedly present at the airport and witnessed the aircraft’s final moments. Emergency services had to respond not only to the crash site but also to the needs of those who had been waiting for the flight or knew the people on board.
For the families, the technical investigation may provide answers, but it cannot undo what happened.
The people aboard had individual lives, relationships, plans, and reasons for taking part in the activity. The five novice participants were preparing for a special experience, while the instructors were carrying out a professional role that involved helping others take part in parachuting.
Their deaths should not be reduced to a sequence of engine readings and flight parameters.
The investigation matters because the answers may help prevent another tragedy. But remembering the victims also means recognizing the human lives behind the numbers.
The emergency response in Tomblaine
The crash took place near a residential area, creating an immediate emergency for the surrounding community.
Police, firefighters, medical teams, and specialist investigators were mobilized. The area had to be secured, the wreckage examined, and the victims identified.
The French National Gendarmerie later described the extensive work carried out by its investigators and forensic specialists. This included identification procedures, technical examinations, and detailed documentation of the crash site.
Gendinfo, Gendarmerie nationale
The scene required careful handling because investigators needed to preserve evidence while emergency services carried out their responsibilities.
A crash site is not simply a place where wreckage is collected. Every part of the aircraft, every recorded parameter, and every physical trace may help establish what happened.
That is why the investigation requires patience and a systematic approach.
Why aviation investigations take time
People often expect investigators to announce a cause soon after a crash. But a preliminary report is only one stage of the process.
Investigators may need to dismantle engines, test components, analyze fuel, examine electrical systems, review maintenance records, and compare recordings from different sources.
Some examinations require specialist laboratories or the involvement of manufacturers. In the Tomblaine case, the planned examination of the turboprop engine in Canada illustrates the international cooperation involved.
The investigators must also ensure that their conclusions are supported by evidence. A theory that seems plausible at first may be rejected when the physical examinations are complete.
The process can be frustrating for families and the public, but a careful investigation is more valuable than a quick explanation that later proves incorrect.
Final Thoughts: The Warning Came First, but the Cause Is Still Unknown
The preliminary findings from the Tomblaine crash reveal a frightening sequence.
During the take-off, an instructor noticed what appeared to be smoke near the front-right section of the cabin. A second instructor raised the same warning. The side door was partially opened to ventilate the cabin.
Shortly afterward, the engine’s gas-generator speed decreased by around 10 percent. The propeller speed briefly fluctuated. The aircraft’s pitch increased, its speed began to fall, and the stall warning sounded repeatedly before becoming continuous.
The aircraft entered an asymmetric stall and struck the ground.
All 11 people aboard died.
The investigation has already established several important details. The aircraft was not overloaded. Its centre of gravity was within the approved range. The pilot was highly experienced, and the weather conditions were generally favorable, although temperatures were high.
Investigators also found three warning indicators that may have been illuminated at impact, but they have not yet established exactly when those alerts appeared. The electrical and air-conditioning examinations did not reveal obvious signs of overheating, and no visible smoke appeared in the available recordings.
The engine, fuel system, and recorded flight data remain central to the investigation.
The most important question is still unanswered: what caused the reported smoke and the sudden change in engine performance?
Until the final investigation establishes the cause, no single mechanical failure, pilot action, or environmental factor should be presented as the definitive explanation.
The preliminary report has revealed the final moments of the flight with remarkable detail. The next stage is to understand why those moments unfolded as they did—and what can be learned to make future flights safer.
Investigators examining the wreckage of the Pilatus PC-6 after the Tomblaine crash.