Source – FAA:
Press Release – FAA Statement on Malaysian Air Flight 17
For Immediate Release
July 17, 2014
Contact: Kristie M. Greco
Phone: (202) 267-3883
The FAA was in contact with US carriers following the crash of Malaysian Air Flight 17. The agency confirms that carriers have voluntarily agreed not to operate in the airspace near the Russian-Ukraine border. The FAA is monitoring the situation to determine whether further guidance is necessary.
On April 3, the FAA issued a Notice to Airman (NOTAM) prohibiting U.S. flight operations until further notice in the airspace over the Crimean region of Ukraine, and portions adjacent to the Black Sea and the Sea of Azov.
The NOTAM does not currently cover the airspace where Malaysian Air flight 17 crashed.
This action was taken due to the unilateral and illegal action by Russia to assert control over Crimean airspace, including international airspace administered by Ukraine without agreement by the International Civil Aviation Organization (ICAO).
This creates the potential for conflicting air traffic control instructions from Ukrainian and Russian authorities and for the related potential misidentification of civil aircraft in this airspace. This prompted the FAA NOTAM for U.S. flights.