Why would a helicopter crash?
“It is a very low probability that the high-tension line there was not known,” a retired helicopter pilot said after a crash last week in the southeastern province of Şırnak killed 13 soldiers. “It is a wide region. There are dozens of high-voltage transmission lines. They are known to pilots but maybe because of the surrounding light conditions, it could have escaped attention.”
The military pilot who served in the region for many years continued: “It is not possible to keep all of them in your memory.” There are land navigation maps on which the obstacles are all marked and are especially prepared for helicopter pilots, he said. All the high-voltage transmission lines are marked on these maps.
Then why would such an accident occur when the location of the high-tension line is known?
As background information, the retired pilot said: “A precise understanding can only be reached after the accident investigation report is issued. But we can also say that an accident generally happens when more than one factor comes together. The critical issue here is to consider all the possibilities that might cause an accident and take all the measures beforehand. Technology has reached a stage where accidents now happen due to human factors to a great extent. But putting the pilot at the center of human error is not right. Everyone who has an input at any stage of the flight is included in this human factor.”
After this background, let us take a closer look at the possible causes of the accident and security systems. Pilots serving in the southeast come from four different regiments under the Army Aviation Command in Ankara and take turns serving in the region. The rotating squads serve for 15 days and then go back to their units in Ankara, İzmir, Istanbul and Malatya.
The number-one danger for pilots in the area is high-tension lines; similarly, there are the antennas of relay stations and TRT transmitting stations – in short, there are all kinds of obstacles on the flight route.
If the flight was done at twilight, then it had an extra difficulty in terms of night vision goggles, according to our source: “A flight with night vision goggles is a difficult one because it provides limited vision with a reduced angle of vision. Instead of 180 degrees, these goggles provide a vision angle of 40 degrees. It may cause difficulty in noticing obstacles; especially when flying westward in twilight when the silhouette of the obstacle does not fall on the horizon. The light sensors may be deceptive in night visions goggles. Also night flights are conducted at low altitudes, leaving you more open to contact with obstacles.”
A measure against obstacles would be equipping the helicopters with radars and laser scan systems that would warn ahead. However, this technology is still being developed and the first models are heavy, affecting the central balance system of the chopper.
Like an automobile’s advanced GPS system, there are “moving maps” for the helicopter. By developing the software, geographic obstacles can be uploaded to these maps. There is a detailed database at the General Command of Mapping where all obstacles higher than 30 meters are marked. If these two factors are merged, this kind of software would be very effective, the retired pilot believes.
Another measure is what is called Enhanced Ground Proximity Warning System (EGPWS). It is the software that verbally warns the pilot about approaching obstacles.
The painting of the tops of pylons with bright colors has been introduced as a measure in recent years. Also, orange balls are placed on the lines. These measures which are highly effective at daytime are no good at night. The one and only measure seems to be illuminating them. As a matter of fact, International Civil Aviation Organization (ICAO) has introduced a series of new standards where all towers, antennas and poles over a certain height should have blinkers which are clearly seen from kilometers ahead.
Human factor
In the final analysis, it is a human being who flies the helicopter and anything that affects their psychology and distracts their attention can cause an accident. Not being rested adequately, as well as experiencing a trouble that occupies their minds, can be a factor that triggers an accident. The experienced pilot we spoke to said, “For this reason all the active and passive measures offered by technology should be taken exhaustively so that any gap that might stem from the human factor is filled.”
At this point, it can be argued that as well as Air Force pilot staff, the staff of Army Aviation Command has gone through certain troubles, having been affected by the July 15 coup attempt. It is not a secret that this command has experienced serious tribulations because of July 15. Quite a number of helicopter pilots are now in prison because they allegedly participated in the coup attempt. Thus, it is possible that the number of active pilots have shrunk to a certain amount, creating problems.