* Asiana says decided to detour for safety reasons
* Shifting routes costs airlines time and money
* IATA says route not restricted; FAA barred US airlines in April (Updates with more detail on airlines shifting routes, FAA and IATA advice)
By Jane Wardell
SYDNEY, July 18 (Reuters) - Some international airlines, including Australia's Qantas Airways and Korea's two major carriers, shifted the route taken by flights operating over Ukrainian air space months ago amid increasing tensions between Kiev and pro-Moscow rebels.
The airlines took extra security precautions despite no official ban from regulators on flying through the area, even as others continued to use the route.
"Although the detour adds to flight time and cost, we have been making the detour for safety, and until the Ukrainian situation is over we will continue to take the detour route for our cargo flight out of Brussels," an Asiana Airlines Inc spokeswoman told Reuters.
A Malaysian Airline System Bhd (MAS) plane was brought down in eastern Ukraine on Thursday, killing all 298 people on board, in what the United States said was probably a ground-launched missile strike.
Australian Prime Minister Tony Abbott said it appeared that "Russian-backed rebels" were responsible.
The International Air Transport Association (IATA) said after the crash that "based on information currently available it is believed that the airspace that the aircraft was traversing was not subject to restrictions".
However, the U.S. Federal Aviation Administration (FAA) issued an order prohibiting U.S. aircraft from flying in the airspace over the Crimean region of Ukraine and nearby parts of the Black Sea and Sea of Azov. The FAA order is in force until April 27, 2015.
"It's blatantly obvious they shouldn't have been anywhere near it," said Geoff Dell, an accident investigation and safety specialist at CQUniversity in Australia, of Flight MH17.
"Any sort of unrest breaks out, civil wars or such, you change your flight path so that you don't go anywhere near it," said Dell, who was working as a senior safety manager for Qantas during the first Gulf War. "Of course it comes at a cost because you have to fly further."
Asiana said it shifted its once-weekly cargo flight some 150 km (93 miles) below Ukrainian airspace on March 3 amid the deteriorating geopolitical situation over the Crimean peninsula. Korea Air Lines Co Ltd switched its flights at the same time.
Qantas said it moved the flight path for its London to Dubai route that passed over Ukraine some 400 nautical miles (740 km) to the south "several months ago".
Cathay Pacific Airways Ltd said it adjusted its routes some time ago, without giving a timeframe.
Several other airlines have continued to fly the route.
Data from airline tracker Flightradar24 shows other commercial flights in the area at the time of the crash. A Singapore Airlines flight and an Air India flight were around 24 km (15 miles) away, according to the data. (Additional Reporting by Lincoln Feast in SYDNEY, Joyce Lee in SEOUL and Donny Kwok in SINGAPORE Editing by Paul Tait and Stephen Coates)