Earlier Monday, U.S. President Barack Obama demanded that Russia use its influence over the rebels to open the crash site to international investigators.
"They need to be able to conduct a prompt and full and unimpeded as well as transparent investigation. And recovery personnel have to do the solemn and sacred work of recovering the remains of those who were lost."
Rebel leader Alexander Borodai, the self-declared Prime Minister of the Donetsk People's Republic, said, "We believe these are the black boxes and these boxes will reveal the truth."
Borodai handed the black boxes over to Malaysian Col. Mohamed Sakri at the headquarters of the rebel movement, and signed a memorandum that Sakri would then transfer the black box to International Civil Aviation Organization experts.
How useful will the black box be to investigators?
UPI spoke with a pilot with 20 years experience, who asked not to be identified for privacy reasons, about what exploitation of Malaysia Airlines Flight 17's black box could yield.
It is possible, he said, that "the Flight Data Recorder may record some of the flight parameter that might give a clue as to how it came apart."
But as for the Voice Data Recorder, "it is unlikely [the pilots] were aware that a missile had locked on them ..."
Flight 17 was struck by a surface-to-air missiles. A radar-guided missile, versus a heat-seeking missile, "is aiming for the mass body of the plane, not an engine." Such a strike would have resulted in "fast decompression," rendering probably everyone unconscious.
"Typically the missile is attacking from below [and] behind, which is a blind spot for the pilots. Civilian aircraft except Israeli El-Al have no missile detection or avoidance equipment."
Ultimately, the pilot concluded, "The black boxes won't tell much."
On Wednesday morning, a train transporting the remains of the passengers arrived in the government-controlled Ukrainian territory of Kharkiv from Donetsk.
The bodies had been placed in five refrigerated train compartments and were under police guard after arriving at the Kharkiv-Balashivsky station.
Once the engine is replaced, the train will be moved to the Malyshev Plant. The bodies will be loaded into containers from the Netherlands, and the remains will then be taken to the Netherlands.
The majority of the 298 passengers aboard Flight 17 were from the Netherlands.