Investigators have disclosed that, in the three days before Malaysia Airlines flight MH17 was shot down, 61 carriers flew through the same sensitive region of airspace.

The three-day period followed the introduction of altitude restrictions on 14 July 2014, ordering civil aircraft to operate above 32,000ft in eastern Ukraine.

On the same date an Antonov An-26 aircraft had been shot down at a height of 6,500m (21,300ft) – indicating an attack by a sophisticated weapon. But Ukrainian authorities told the Dutch Safety Board that this attack, while accelerating the closure, had not triggered it.

Despite the An-26 attack and the tighter restrictions there was “no noticeable change” in air traffic behaviour, says the Dutch Safety Board in its inquiry into the loss of MH17.

Over the three days between the altitude limitation and the destruction of the Boeing 777 on 17 July, it says, 61 operators from 32 countries – including Russia and Ukraine – flew over the area.

Investigators have disclosed that 160 flights operated through the critical area of the Dnipropetrovsk flight information region on the day of the shootdown.

The airspace had not been closed above 32,000ft and MH17, operating at 33,000ft, was not subject to any restrictions.

“Ukraine had sufficient reason to close the entire airspace over the eastern part of Ukraine as a precaution,” the inquiry says.

But Ukrainian air traffic service UkSATSE told the inquiry that the airspace could only be closed if there had been an official request from competent authorities or if there was information relating to a risk to civil aviation.

“Neither of these scenarios applied,” says the inquiry, pointing out that the Ukrainian authorities believed there were “no grounds” to suspect a threat to civil aircraft above 26,000ft, taking into account an additional buffer which set the limit at 32,000ft.

Attacks on civil aircraft were “not considered as a realistic scenario” by military authorities, the inquiry says, partly because they believed armed groups in the region possessed shoulder-launched weapons with a maximum altitude range of 4,500m.

“On military grounds flying at lower altitudes was restricted,” says the inquiry. “The same turns out to apply to conflict areas elsewhere in the world: it is rare for a state to close its airspace because of an armed conflict.”

Investigators considered whether the Ukrainian authorities kept the airspace partially open to ensure no interruption to air traffic services revenues. Eurocontrol data shows that Ukraine received nearly €200 million in airspace revenues in 2013.

UkSATSE estimated that the subsequent closure of east Ukrainian airspace – imposed after the loss of MH17 – resulted in a 7-9% fall in revenues against the 2014 budget.

But UkSATSE insisted to the inquiry that the decrease in revenues “played no role” in the decision to restrict use of the airspace.

Source: Cirium Dashboard