Malaysia Airlines flight MH17 was on a routine flight from Amsterdam to Kuala Lumpur when it crashed, apparently after being hit by a missile.

The jet was travelling east across Ukraine along an airway designated A87. Eurocontrol, the co-ordination centre for air-traffic control in Europe, said: “This route had been closed by the Ukrainian authorities from ground to flight level 320 [32,000 feet] but was open at the level at which the aircraft was flying.” The plane was flying at the lowest permitted altitude over the area, flight level 330 [33,000 feet], when it disappeared from the radar.

Since the crash, all the airspace of eastern Ukraine has been closed to civil aircraft until further notice. Flight plans submitted by pilots are automatically checked against closed areas of airspace. Eurocontrol said: “All flight plans that are filed using these routes are now being rejected.”

As the security situation in Ukraine deteriorated in April, the US Federal Aviation Administration issued a warning to American pilots and airlines operating in the region. The “Notam” (Notice to Airmen) ordered “Exercise extreme caution due to the continuing potential for instability”.

Nevertheless, civil aviation continued to fly over the conflict zone, along airways that normally carry thousands of passengers on dozens of flights each day.

Since the news broke, many passengers have expressed astonishment that commercial flights should be routed over a conflict zone such as eastern Ukraine. One traveller, Nicholas Eeley, said: “I cannot believe that civilian aircraft blithely overfly active battle zones. How bad does it have to get to order a fly-round?”

VIDEO: MALAYSIA AIRLINES FLIGHT MH17 CRASH