The way I see it...
The Ukrainian Army used its Buk Missile system from Donetsk to try to frame the local Militia by moving the Buk missile system to a militia controlled area just prior to the launch/crash.

An Army controlled Ukrainian Su-24/25 fighter jet was used as the initial target for the Buk system (which has safeguards preventing it from directly targeting a commercial airliner such as MH17). Once the Buk missile system was in place on militia controlled land, the Su-24/25 fighter jet flys by and gets locked on. Once the Buk missile is fired (by the Ukrainian government, but on militia controlled land) it then chases the Su-24/25 fighter jet, which quickly gains altitude and flies in a general path towards MH17. Shortly before impact the Su-24/25 fighter jet drops chaff, which is then hit by the Buk missile instead of the fighter jet. At the same time the Su-24/25 fighter jet then shoots a air-to-air Vympel R-60 missile (from ~3.5km away) at MH17, which mimics the original Buk missiles pathing and then ends up hitting the left engine of MH17 as if it were the Buk missile, causing MH17 to crash.

The Su-24/25 fighter jet then lands as if it was never there, and the Buk missile system is removed from militia controlled land and moved back to Donetsk where the Ukrainian Army denies it's involvement in the event and passes blame on to Russian militia instead.

And go figure...

Ukrainian President Petro Poroshenko said on Monday that Kiev has “strong evidence” of the causes of the MH17 crash.
“We know exactly the place [the surface-to-air missile was] launched, we know exactly the place where it hit the civilian plane and the place where the plane crashed.”

Ya because they are going to point all the attention to the Buk missile decoy that was purposely launched from militia controlled land to keep the public from learning the truth about what really happened...

It's amazing more people aren't seeing this event for what it was (they did the EXACT same bait and switch in Syria recently but using chemical weapons instead, and using the rebels to try to frame the government, instead of the government to frame the rebels... same shit different day).


Ukrainian Army Buk Missile System Transported to Militia-Held Area Just Prior to Crash
While the third picture shows the location of the air defense systems near Donetsk, he explained...
“Images from this area were also made on July 17. One should notice that the missile launcher is absent [from the scene]. Image number five shows the Buk missile system in the morning of the same day in the area of settlement Zaroschinskoe...
The question that has to be answered is why the missile system appeared in the area controlled by the local militia forces shortly before the catastrophe, he stated.
Images taken on July 18 show that the missile systems left the area of the MH17 crash, the military official said.

Ukrainian Su-25 fighter detected in close approach to MH17
“A Ukraine Air Force military jet was detected gaining height, it’s distance from the Malaysian Boeing was 3 to 5km,” said the head of the Main Operations Directorate of the HQ of Russia’s military forces, Lieutenant-General Andrey Kartopolov speaking at a media conference in Moscow on Monday.
“[We] would like to get an explanation as to why the military jet was flying along a civil aviation corridor at almost the same time and at the same level as a passenger plane,” he stated.
“The SU-25 fighter jet can gain an altitude of 10km, according to its specification,” he added. “It’s equipped with air-to-air R-60 missiles that can hit a target at a distance up to 12km, up to 5km for sure.”

Ukraine’s Kupol-M1 9S18 radar (which are part of the Buk system) activity increased prior to crash
"..there were 7 radars operating on July 15, 8 radars operating on July 16, and 9 radars operating on July 17 in the area. Then, starting with July 18, the intensity of radar activities radically decreased, and now there are no more than two or three radars operating a day. The reason behind this is yet to be found."

[link to rt.com]