KARACHI: National carrier Pakistan International Airlines (PIA) on Friday said it stopped all flights flying over Ukraine nearly three months ago after tensions between Russia and Ukraine escalated over territorial control of Crimea.

As international carriers diverted flights going through Ukranian airspace in the aftermath of the deadly Malaysian Airlines jetliner crash on Thursday, spokesperson for PIA Mashood Tajwar told Dawn that the airline had made a decision to stop flying via Ukrainian airspace for security reasons.

“Our flight operations department constantly monitors all routes and paths. When the Crimea crisis developed earlier this year, we received a report that a [military] plane had been shot down by insurgents. At this point the decision to halt this route was taken.”

Tajwar said that while airspace over the region was earlier under Russian control, it came under dispute between Ukraine and Russia when tensions between the countries soared, making it unclear which of them would be authorised to grant flying permission.

“Ukraine said Russia no longer has control over that airspace,” he added

For Asia flights flying West, Tajwar said there are three possible flight routes; North (Russian airspace), South (Turkey, Azerbaijan, Caspian Sea etc) and Ukraine/Crimea.

“The Ukraine route is preferred because it is less time-consuming. The others take up to 20 minutes extra flight time compared with the other routes, which means more time and fuel cost. We decided to bear that extra burden and discontinue using Ukrainian airspace,” he said.

According to Tajwar, PIA had at least five flights going via Ukranian airspace per week.

“It is difficult to quantify extra costs as it varies with each airline, however, if you are flying a Boeing 777, an extra 10 to 15 minutes can incur costs of Rs1 million,” Tajwar said.

At the end, the spokesperson said that the change in flight operations was not announced to the public as it was an internal operational matter.

Ukraine has accused “terrorists” - militants fighting to unite eastern Ukraine with Russia - of shooting down the Malaysia Airlines Boeing 777 with a heavy, Soviet-era ground-to-air missile as it flew from Amsterdam to Kuala Lumpur.

The Telegraph reported that South Korea's main airlines, Korean Air and Asiana, as well as Australia's Qantas and Taiwan's China Airlines said they had re-routed flights from the beginning of March when Russian troops moved into Crimea.

The report also quoted Malaysian Prime Minister Najib Razak as saying that Malaysian Airlines had not taken similar precautions because the route had been deemed secure.

"The aircraft's flight route was declared safe by the International Civil Aviation Organisation. And (the) International Air Transportation Association has stated that the airspace the aircraft was traversing was not subject to restrictions," he said.