Er Srbija u fokusu / Air Serbia close up
KAPETAN Nenad Breberina Captain
ZAŠTO AVION U JEDNOM SMERU LETI DUŽE ILI KRAĆE NEGO U DRUGOM? WHY DOES THE PLANE TAKE LONGER TO ARRIVE FLYING IN ONE DIRECTION THAN THE OTHER? P S
onekad se dešava da u jednom smeru ka destinaci- ji letite određeno vreme, a da se u povratku na toj istoj ruti vozite malo duže ili malo kraće. Ta odstupanja su na kratkim letovima uglavnom zanemarljiva i može se desiti da se odlazak i povratak razlikuju do 20 minuta, ali na dugim relacijama vremenska razlika u trajanju le- ta može biti mnogo duža, čak i do dva sata na našem le- tu za Njujork, recimo. Razlog što se ovo ponekad dešava veoma je jedno- stavan. „Kriv“ je vetar. Na velikim visinama može da du- va i oko 200 kilometara na čas, što značajno utiče na let. Naime, ako vetar duva u pravcu u kojem letimo, da- kle ako nam je iza leđa, praktično nam pomaže i leteće- mo kraće. Ukoliko je situacija obrnuta, pa nam jak vetar duva u kljun, let će trajati nešto duže. Pojava ovog vetra je potpuno normalna i bezopasna, a u vezi je sa rotaci- jom Zemlje. Ledene mlazne struje stvaraju neku vrstu cevi, tako su i prikazane, te mi unapred, zahvaljujući svim tehnič- kim i tehnološkim dostignućima i meteorološkim poda- cima, znamo gde da ih očekujemo. Budući da let treba da bude najavljen 24 sata unapred, u skladu sa podacima bi- ramo i rute na kojima ćemo leteti, između ostalog i zbog određenog vetra. Ukoliko nije gužva i možemo da dobi- jemo visinu koju želimo, letećemo na većim visinama jer je vazduh ređi i brže se leti, dok je na manjim visinama situacija obrnuta – letimo malo sporije, što takođe može da utiče na to da let u oba smera traje različito.
ometimes it occurs that the flight to your destination takes a certain amount of time in one direction, and the return flight on the same route is slightly longer or shorter. These deviations are generally negligible on short trips, where outbound and return flights can be as little as 20 minutes, but over longer distances the flight-time difference can be much longer – even up to two hours on our New York flight, for instance. The reason this sometimes occurs is very simple. The “guilty party” is the wind. At high altitudes it can blow at around 200 kilometres per hour, which has a significant impact on the flight. Specifically, if the wind blows in the direction we are flying, and is thus at our backs, it helps us and shortens our flight. If the situation is reversed and a strong wind blows into the nose of the plane, the flight will take longer. The presence of this wind is completely normal and harmless, and relates to the earth’s rotation. Icy jet streams create a kind of tube, which we know about in advance thanks to the technical and technological advancements in our tools and the meteorological data we have. We know where to expect them. Considering that a flight must be confirmed 24 hours in advance, we choose the routes on which we will fly, in accordance with the available data, based, among other things, on the particular wind situation. Provided that a route is not crowded and we can get the altitude we want, we fly at higher altitude because the air is thinner and we fly faster, while at lower altitudes the situation is reversed – so we fly a little slower, which can also have an impact on flight times in both directions.
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