KUALA LUMPUR - Malaysia Airlines rerouted a flight over Syria on Sunday after its usual path over Ukraine was closed, reflecting the challenges airlines face in finding conflict-free routes between Asia and Europe.
After Malaysia Airlines Flight MH17 was shot down Thursday by a ground-to-air missile in eastern Ukraine, airlines began to avoid the airspace above where the Ukrainian military has been fighting Russian-backed rebels.
Swedish flight tracking service Flightradar24 AB posted a flight map on its Twitter account on Monday showing the change in the route of Malaysian Airlines flight MH4, which flies from Kuala Lumpur to London.
Flight tracking data showed this flight had previously crossed over eastern Ukraine. (Flight path: bit.ly/1wPJDUr)
Syria is in the middle of a civil war in which 170,000 people have died since 2011.
Fredrik Lindahl, chief executive officer of Flightradar24 AB, said it was relatively unusual for transcontinental flights to cross Syria.
"With Iraq you always see aircraft flying there. There is no other way to access parts of the Middle East than to use the Iraq corridor," he said.
"But you don't see Syria so often. We saw no other trans-continental flight that went through Syrian airspace yesterday."
Some regional traffic uses Syrian airspace including a Middle East Airlines flight bound for Beirut on Monday, according to the Flightradar24 website.
Malaysia Airlines said MH4's flight plan was in accordance with the International Civil Aviation Organization's (ICAO) approved routes.
"As per the notice to airmen (NOTAM) issued by the Syrian Civil Aviation Authority, the Syrian airspace was not subject to restrictions," Malaysia Airlines said in a statement. "At all times, MH4 was in airspace approved by ICAO."
ICAO, which said last week it had no operational role and did not have the authority to open or close routes, did not respond to repeated requests for comment on Monday.
Kenneth Quinn, a former chief counsel at the U.S. Federal Aviation Administration and secretary of the U.S.-based Flight Safety Foundation, questioned the wisdom of flying "over hotly contested territory" but said he was not aware of a credible threat against airliners flying in Syrian airspace.
Tim Clark, president of Emirates Airlines, one of the world's largest airlines, said it was difficult to avoid flying over conflict zones on main routes between East and West.
Airlines assume that when a flight plan is accepted in controlled airspace, it is safe to fly on that particular route, Clark said on Sunday. There may have to be changes in the way the industry assesses such risks in light of the MH17 disaster, he added.
Hundreds of flights routinely crossed over Ukraine before Thursday's incident, and it is not unusual for international airlines to fly over war zones such as Afghanistan.
John Saba, a lecturer at McGill University's Integrated Aviation Management Programme in Montreal, said he did not think the Syrian government would fire missiles at airliners.
"The question is: who has access to these (missiles) and what is the range?" he said.
The U.S. Federal Aviation Administration, whose regulations are among the world's strictest, "strongly discourages" U.S. operators from flying to, from or over Syria, according to a May 2013 notice on its website.