Others about us – Article on air traffic by Srna

As many as 2,500 aeroplanes fly through Serbian airspace every day and not a single aircraft passes through it unnoticed.

Others about us – Article on air traffic by Srna

25.06.2013

BELGRADE, JUNE 21/SRNA/ – As many as 2,500 aeroplanes fly through Serbian airspace every day and not a single aircraft passes through it unnoticed, so there is no cause for concern that `unmarked` aeroplanes release toxic substances spraying them on the local population and in the environment, claim the experts and competent services.

According to the theories which have appeared in the media, the aeroplanes leaving long white trails are used for conducting experiments in the Earth`s atmosphere, and when the substances from those clouds fall onto the ground, they turn into a white cobweb and cause serious diseases.

The proponents of this theory, widespread both in our country and the world, cite, as one of the main arguments, the fact that the trail left by some aeroplanes is unusually wide and that it remains in the sky for a conspicuously long time.

However, as the experts point out, the trails that we can see behind jet aircraft are in fact condensed water vapour and exhaust gases, and the difference in the shape and size is a normal phenomenon attributed to different altitudes the aircraft fly at.

Mr Slobodan Gvozdenović, Head of the Department of Air Traffic and Transport at the Faculty of Traffic and Transport Engineering in Belgrade, explains for SRNA that the air temperature at the altitudes aircraft fly at, and that is about 11 kilometres, is around minus 54 degrees.

As a result of kerosene combustion, exhaust gases, reaching the temperatures of up to plus 250 to 300 degrees, are emitted from the aircraft engines into such environment, so that, as Professor Gvozdenović says, hydrocarbon condenses and water vapour is created.

Since the air flows above and below aircraft wings, vortices are formed, which we, looking up from the ground, see as white stripes. Their shape depends on the altitude, wind, humidity and temperature, and they are more clearly visible when the air is drier.

Professor Gvozdenović, however, points out that the problem is not what we see, but what we do not see, and which has nothing to do with conspiracy theories, and that is the emission of noxious gases typical of air traffic in the whole world.

“Burning of one kilogramme of fuel used by aircraft engines – kerosene, produces 3.2 kilogrammes of carbon monoxide, which, together with other chemical compounds, is harmful and contributes to the `greenhouse effect` and global warming,” said Mr Gvozdenović in his statement to SRNA.

Lavatory waste dumping in the air is forbidden and the waste disposal is conducted exclusively on the ground, and the only thing that is allowed to be released in the air is a small amount of fuel, but only for safety reasons in emergency situations.

“If an aeroplane which has taken off from Banja Luka, for example, bound for Belgrade, experiences a failure due to which it has to return to Banja Luka immediately, it is not supposed to land with the same weight if it is considerable. In other words, an aircraft is designed to perform the flight, burn the fuel and land with the landing weight being lower than its initial weight. It is possible, in that case, to dump a small amount of fuel out of the fuel tank at a prescribed altitude of not lower than 6,000 metres so that the aircraft could land safely, but it happens very rarely,” explained Mr Gvozdenović.

In a statement made to SRNA, the Civil Aviation Directorate (CAD), which is responsible for the safety of air traffic, said that in the previous years there had been only a few reports made by local inhabitants and some environmental associations of suspicious white trails in the sky noticed in some towns, and not a single one since the beginning of the current year.

The CAD has investigated all the reports, and has established, in cooperation with Serbia and Montenegro Air Traffic Services SMATSA llc, that there have been no unannounced, suspicious or unknown aircraft or any knowledge whatsoever that somebody has been releasing powdery substances. The aircraft that the local inhabitants have regarded as suspicious have been mostly passenger aircraft.

Representatives of Serbia and Montenegro Air Traffic Services SMATSA llc, in Belgrade, which provides air traffic control services in the airspace over Montenegro, Serbia and in the 55 per cent of the airspace over Bosnia and Herzegovina above 29,500 feet /approximately nine kilometres/ point out that the volume of air traffic today is considerably higher than it was ten years ago.

“Traffic density in this part of Europe almost equals the volume of traffic in the most developed part of Europe, and when it comes to the region, the air traffic control centre in Budapest handles a slightly higher number of aircraft, whereas other centres in this region have lighter workloads than the centre in Belgrade,” said Mr Bruno Genal, SMATSA ATCC Director, in a statement to SRNA.

At this moment, in the middle of June, as Mr Genal explains, 2,100 to 2,200 aircraft fly through our airspace every day over weekends, and the number of aircraft in the peak periods of a day is 150 to 140 aircraft an hour.

In the middle of July and later on in August the figures rise to over 2,500 aircraft a day, that is, to as many as 200 aircraft an hour.

He states that 89 per cent of the aircraft are aircraft overflights and 11 per cent are aircraft taking off from and landing at regional aerodromes or at aerodromes located in the vicinity of the borders, such as Skopje, Dubrovnik, Tirana, Timisoara and Budapest.

“Every aircraft is announced prior to entering the airspace under our jurisdiction on one hand, and, on the other hand, competent military authorities are informed about it, so that uncontrolled entry is absolutely impossible. Such aircraft has to establish radio contact with us, which means that we have radar and radio contact with it, and what is more, all neighbouring air traffic control centres are familiar with its flight plan,” points out Mr Genal.

Should any aircraft enter the airspace of our country and did not want to establish radio contact, as Mr Genal explains, it would be seen on the radar by the ATC, and in case of an unannounced aircraft, there is a procedure in place to be followed in coordination with the competent military authorities.

“I do not recall any event of that kind,” Mr Genal concluded.