According to a Dutch preliminary report, Malaysia Airlines flight MH17 broke up in mid-air after being hit by “numerous objects” that “pierced the plane at high speed”.
The report released by the Dutch Safety Board said there was “no evidence of technical or human error”.
All 298 people on board died when the plane came down, amid reports it was shot down by pro-Russian rebels.
The plane was flying from Amsterdam to Kuala Lumpur when it crashed in eastern Ukraine.
Dutch aviation investigators relied on information from the black box flight data recorders, air traffic control, satellite images and photos from the scene to compile the preliminary report.
They said the plane “broke up in the air probably as the result of structural damage caused by a large number of high-speed objects that penetrated the aircraft from outside.”
The cockpit voice recorder revealed no signs of any technical faults or an emergency situation, the experts said.
The Malaysia Airlines Boeing 777 crashed between Krasni Luch in Luhansk region and Shakhtarsk in the region of Donetsk on July 17.
Ukraine’s government and several Western leaders say there is strong evidence that pro-Russian separatists shot down the plane with an anti-aircraft system known as Buk.
Russia has consistently denied allegations that it had supplied any missiles or weapons to the rebels.
Experts from Germany, Australia, Malaysia, the US, the UK, Ukraine and Russia are collaborating on the case.
The board says it expects the final report to be published within a year.