It was then transported back across the border to Russia and has not been seen since.
Russia has consistently denied allegations that pro-Moscow rebels in eastern Ukraine were responsible, and has slammed the report findings as "biased" and "politically motivated".
McCully praised the report as being based on "painstaking, impartial and careful investigation".
It raised "some very serious questions", he said.
"The Joint Investigation Team's release of its preliminary findings is an important step towards accountability.
"New Zealand continues to urge all countries to fully cooperate with this investigation, as required under Security Council resolution 2166.
"The victims of this tragedy and their families deserve this much."
A New Zealand resident, Robert Ayley, from Otaki was killed, as was a New Zealander, Mary Menke, who had been living in Australia with her Dutch husband.
The focus will now shift to what happened to the Buk once it crossed back into Russia minus one of its missiles.
The JIT said it is investigating 100 people of interest, with the ultimate aim of bringing them to justice in court.
Ukraine's foreign ministry said the findings proved Russia's "direct involvement" in the downing of the plane and branded the country an "aggressor".
- Additional reporting news.com.au