According to an authoritative source, two Su-27 Flankers escorted the Malaysian Boeing 777 minutes before it was hit by one or more missiles.

There are still too many unanswered questions about the downing of Malaysia Airlines MH17 over eastern Ukraine on Jul. 17, 2014. Among them, one of the most important deals with the possible error made by the operator inside the SA-11 “Gadfly” (“Buk”) TELAR (transporter erector launcher and radar) who did fire one or more missiles against a civilian plane.

Indeed, the operators inside the Buk could “read” the Boeing 777′s altitude and transponder and could easily identify the civilian plane enroute from Amsterdam to Kuala Lumpur flying at FL300 inside the eastern Ukraine’s airspace.

Why did they mistake a large civilian plane for a smaller Ukrainian Air Force surveillance plane?

Just a matter of poor training?

Iranian defense expert Babak Taghvaee believes the mistake was caused by the fact the Malaysian Boeing 777 was escorted over eastern Ukraine.

Taghvaee is always very well informed and an extremely reliable source. Therefore, after he provided some details about this activity of the Ukrainian Air Force on ACIG forum thread about the war in Ukraine, we contacted him for some more insight.

Here’s what he wrote to us.

“When the Crimea crisis began, the Ukrainian Air Force air command center quickly forward deployed six Su-27s to the Kulbakino AB. Since beginning of the crisis and the Russia intervention, the 831st TAB has the important task to provide air defense as well as security of whole country. Six fully armed Flankers have always been in the sky especially when the other Ukrainian Air Force airplanes such as transporters and attackers like Fulcrums and Rooks were in the East of Ukraine,” explains Taghvaee.

“But when the Su-25M1 was shot down by the Russia Air Force 6969th AB’s MiG-29 on Jul. 16, the situation and condition became more critical than previous days and more Su-27 sorties were conducted to confront Russian MiG-29s. I believe those two Su-27s were not in sky just for standard practice in that day [Jul. 17], I believe they were involved in HAVCAP (High  Asset Value Combat Air Patrol) mission sortie in that day.”

In other words: since the Russian interceptors had downed a Su-25 on the previous days, the Ukrainian escorted all military and civil flights over eastern Ukraine on Jul. 17. Including MH17.

“During the UEFA 2012, the 831st TAB and its Flankers had same role, during those competitions they had duty to escort the airliners in FL330 and other routes in case emergency. They played same role during the Sochi Winter Olympics in Russia. They were airborne and they even escorted a hijacked airplane. They were also ready to provide security of all passenger airplanes over Ukraine. They are now following same procedure and they could protect all of the airplanes over Ukraine in-front of Russians since Jul 16.”

Provided the Su-27s were really escorting many, if not all, civil flights over Eastern Ukraine for the first time ever on Jul. 17, in the wake of the downing of the Su-25, the operators inside the Buk may have mistaken the Boeing 777 shadowed by two Flankers for a high-value plane of the Ukrainian Air Force. On their radar screens, the sight of a large plane with two accompanying fighter jets was completely new and may only mean the Ukrainians were escorting an important plane. And that’s the reason why they downed it without spending too much time analysing its transponder code and altitude.