The report from the Dutch Safety Board into the plane crash on the highway near Sint Willebrord was eagerly awaited for months. Ultimately, the disappointing and unsatisfactory conclusion was reached on Tuesday that the cause ‘remains unknown’. According to aviation expert Joris Melkert of Delft University of Technology, this outcome is no surprise.
“In accidents involving this type of small aircraft, the cause can often no longer be determined exactly. Especially when, as in this case, there is virtually nothing left of the wreckage. It was really very sad to see,” says Melkert.
According to the research report, technical defects are virtually excluded. The pilot’s flight movements could have provided more clarity, but they turned out to be impossible to reconstruct due to the impact of the crash.
“Sometimes telephone videos in combination with statements from eyewitnesses can lead to astonishing results. But when this information is insufficient or completely missing, it becomes very difficult for researchers,” says Melkert.
Why small planes don’t have a black box
Large commercial aircraft are equipped with two black boxes (which are actually orange). The cockpit voice recorder records all conversations of the pilots. The data flight recorder records all flight and control data and technical data of the aircraft.
“At least 88 different parameters are recorded. This includes altitude, speed and course direction, but information about, for example, the condition of the engines is also continuously recorded,” Melkert explains.
Small sport aircraft do not have this type of registration equipment on board. This would require many components to be fitted with sensors. “That is complex, expensive and therefore not feasible. In large aviation, this is very different because many lives are involved in an accident. When something goes wrong, we absolutely want to know the cause in order to learn lessons.”
“Since large-scale aviation is extremely safe, general aviation still remains a safe form of transport.”
Melkert continues: “We said for light aviation: it is what it is. We know that this type of air traffic is statistically a factor of ten less safe than large aviation. People generally know that they take a little more risk. Since large aviation is extremely safe, small aviation still remains a safe form of transport.”
Small aircraft do have a transponder that keeps basic information about altitude, speed and location of the aircraft. “The only question is what the added value is in these types of accidents. You mainly want to know whether there were any strange or unexpected movements during the very last phase of the flight. This type of data does not provide an answer to that.”
The outcome of the research is ‘frustrating’
The crashed plane crashed shortly after it took off and, according to eyewitnesses, veered away in a lurching motion. “A stall in a turn at low altitude is a deadly combination. Unfortunately, statistics show that pilot error is often the cause of this.” The aviation expert emphasizes that this is purely a statistic, because the investigation into this crash revealed that the exact flight movements could no longer be traced.
Melkert finds it especially sad that the relatives will never know exactly what happened. “It is of course also annoying for the flying school, which would have liked to know the cause. We do these types of investigations to prevent these types of accidents and that is why it is frustrating in general.”
“I suspect that in the future we will be able to record more and more data with new apps. In my opinion, a decent black box in smaller devices remains a fairly hopeless exercise.”