Crash course

Air France, British Airways, Singapore Airlines and numerous other airlines stopped flying over the war zone in eastern Ukraine some time ago. Others, like German Lufthansa, only now altered their Asia routes - in light of the Malaysia Airlines flight 17 tragedy, in which a ground-to-air missile likely struck the plane, killing almost 300 people.

The airlines are now required to detour around the airspace over eastern Ukraine, since it has officially been closed. It's unusual for such a big area to be closed to passenger aircraft; most of global airspace remains open.

Pilots have the last word

What factors play into a commercial airline's decision by to fly over certain areas - including warzones that remain open? Airlines weigh safety and profitability, said Tim van Beveren, a journalist and aviation expert. He believes many carriers take on avoidable risk to save money. "Unfortunately, money often plays a key role in aviation," he told DW in an interview.

To keep costs down, commercial airlines typically fly the shortest route from point A to point B. But van Beveren pointed out that flight crews also have a voice: "Pilots can always say, I won't accept this route over this conflict area." Ken Thomas from the European air traffic control service Eurocontrol confirmed that pilots have the last word in route choice.

Deciding to detour from a planned route is not a problem for pilots when there is turbulent weather - or other kinds of imminent threats. But if pilots tell their employers that they don't want to fly over a specific area, they will need very good reasons.

Jörg Handwerg, a Lufthansa pilot himself, said pilots would have to provide a very convincing argument to their boss - especially if their colleagues or other airlines continue to use the route.

Below 10,000 meters thought to be safe

In terms of deciding whether airspace is safe or not, that's up to the particular country. Upon deeming an area as dangerous, that country would ban civilian aircraft from accessing it. Before the crash, Ukrainian airspace had been closed from ground elevation up to 10,000 meters (33,000 feet). But it remained open above that.

Handwerg, who is also a board member of the German pilots' association Cockpit, said pilots had been advised to stop landing at eastern Ukrainian airports because of ground fighting. "But there was no apparent threat for flights above 10,000 meters. And, passenger aircraft usually aren't typically targets in such conflicts," he said.

Handwerg drew the following conclusion from the disaster: "My fellow pilots and I will more closely scrutinize decisions regarding which airspace to use and which airports to access in the future." Cockpit's members, said Handwerg, in general oppose commercial airlines flying over war zones. "If it can't be avoided, then our planes ought to get missile defense technology similar to that of military jets," Handwerg said.

Other dangers

Handwerg is also concerned about the fact that virtually anyone these days can check the exact location of a particular plane, including its precise height and speed. "Flight details are transmitted to the ground completely undecoded," he pointed out. That amounts to "free delivery of information to potential terrorists, which makes us vulnerable."

It's still not completely clear whether a missile downed Malaysia Airlines flight 17 on its way from Amsterdam to Kuala Lumpur - though it is looking ever more likely. If that were the case, it most probably wasn't a targeted attack.

Van Beveren already has his eyes on a different country that could become dangerous for passenger aircraft: Israel. "The weapons systems in use could easily strike landing planes - it would be easy to target a commercial plane there."