Task: Question Generation
Input (English): Context : On 12 September 2012 at about 12:20 local time (00:20 UTC), Petropavlovsk-Kamchatsky Air Flight 251, operated by an Antonov An-28, crashed while attempting to land at Palana Airport in Russia. 
Answer : 12 September 2012
Output (English): What was the date of Petropavlovsk-Kamchatsky Air Flight 251?