Ukrainian authorities had raised the upper limit of closed airspace over the east of the country just three days before the loss of the Malaysia Airlines Boeing 777 near Donetsk.
The change appears to have been driven by concerns that more sophisticated surface-to-air weapons were being used to strike targets at higher altitudes, following the crash of a Ukrainian Antonov An-26 on 14 July.
NOTAM data shows that certain routes leading to the TAMAK waypoint – close to where flight MH17 vanished – were subject to closure from the surface to an altitude of 26,000ft from 1 July.
But this restriction was extended upwards to 32,000ft on 14 July, an extension which covered three major routes – airways L980, L69 and M70 – that all converge on TAMAK.
Notably this restriction was imposed on the day that the An-26 was attacked while operating at a height of 6,500m (21,300ft).
Ukraine’s defence ministry informed the country’s president, Petro Poroshenko, that the height of the aircraft excluded the possibility that it had been hit by a shoulder-launched man-portable air defence system.
“Therefore the aircraft was downed by another, more powerful missile weapon that was probably [fired] from the territory of the Russian Federation,” Poroshenko stated.
Ukrainian airspace is traversed by aircraft operating from Europe to south-east Asia, and the great-circle path – the minimum distance between points on the globe – for Amsterdam-Kuala Lumpur, the route flown by MH17, passes through northern and eastern Ukraine.
While the altitude of the 777 at the time of its loss has yet to be conclusively determined, Eurocontrol has indicated that the 777 had been operating at 33,000ft, just above the elevated exclusion zone.
In the wake of the loss of MH17, possibly to hostile action, several extensive airspace and route closures have been put in place.
NOTAMs put in place on 17 July, after the crash of the 777, show that the restriction applies from the surface to an “unlimited” upper altitude, sealing off main airways centred on Donetsk and routes to the TAMAK waypoint, as well as a number of other eastern Ukrainian network points.