According to Interfax-Ukraine, he said that it is impossible to predict how long the investigation will continue.
According to National Post, in an interview on Monday, Kathy Fox, the head of Canada’s Transportation Safety Board, confirmed the long-awaited downloading of crucial flight data and cockpit voice recordings from the Jan. 8 crash was completed successfully in Paris on Monday. The safety board sent a team to Paris to witness the downloading of the data.
She said that Iran has the final say over who gets to analyze the flight data recorders from the Ukrainian passenger jet.
“It’s not clear to us whether some of that work is going to be done in France or whether Iran is simply going to take the data and go back and do it in their country,” Fox said.
Fox also made clear that she was able to say what she did publicly because Iran gave the necessary permission required under international aviation law to do so.
Under Annex 13 of the Convention on International Civil Aviation, the “State of Occurrence” — in this case, Iran — becomes the lead investigator for the crash because it happened in Iran.
But Iran could ask for help from another country or designate another country to lead the investigation, as was the case when Ukraine turned to the Netherlands to lead the probe into the shootdown of Malaysia Airlines Flight 17 by pro-Moscow Ukrainian rebels over eastern Ukraine six years ago.
“ICAO permits countries to delegate. For whatever reason, Iran has chosen to lead it. They have the right to do that,” said Fox.
The Ukrainian passenger plane, with 176 people aboard, was mistaken for an invading missile. The tragic incident happened a few hours after Iran fired missiles at a U.S. airbase in western Iraq in retaliation for the January 3 assassination of General Qassem Soleimani. Following the retaliation attack, the Iranian military had been put on high alert. 
The victims of the crash included 82 Iranians, 63 Iranian-Canadians, 11 Ukrainians, 10 Swedes, four Afghans, three Germans, and three British nationals.