Dutch investigators have confirmed that Malaysia Airlines flight MH17 had been flying an offset course from its airway before the Boeing 777 broke up after sustaining multiple high-energy impacts.
The crew had requested to fly 20nm (37km) to the left of airway L980 about 20min before the loss of the aircraft.
Flightglobal had previously reported that surveillance data had indicated evidence of a possible deviation due to weather as the aircraft passed Dnipropetrovsk.
The Dutch Safety Board has also disclosed that, a few minutes before, the crew of MH17 initially declined to climb from 33,000ft to the aircraft’s planned cruising altitude of 35,000ft.
Dnipropetrovsk area control centre had inquired whether MH17 could execute the climb, in order to avoid a traffic conflict with another 777 which was approach from behind at the same altitude.
“[MH17’s] crew replied they were unable to comply and requested to maintain [33,000ft],” says the preliminary inquiry into the 17 July crash.
After agreeing the weather deviation from airway L980 the crew of MH17 subsequently asked whether there was room to climb to 34,000ft but was told that this altitude was unavailable.
MH17 was still 3.6nm left of the airway just before 16:20, when Dnipropetrovsk centre instructed the flight to proceed directly to Rostov-on-Don, rather than carry on along L980 towards the TAMAK crossing point into Russian airspace.
The crew of MH17 acknowledged the course change to the Rostov-on-Don waypoint, designated RND, stating: “Romeo-November-Delta, Malaysian one-seven.”
This was the last transmission from the aircraft, just 7s before the cessation of the cockpit-voice and flight-data recorders a few seconds after 16:20.
Dnipropetrovsk control tried to inform MH17 to expect a direct clearance to the TIKNA waypoint but its crew did not respond. The controller telephoned Rostov centre, asking whether it had contact with MH17, but was told: “No, it seems that its target started falling apart.”
“At the time of the occurrence the aircraft was flying in unrestricted airspace, under control of [air traffic control], following the route and flying the altitude as cleared by ATC,” says the inquiry.
Three other commercial aircraft had been overflying the same airspace – which had been closed below 32,000ft – at the time. The inquiry says the closest of these was 30km away.
While examination of MH17’s wreckage is continuing, the investigators found multiple punctures – consistent with high-energy impacts – in the forward sections of the aircraft, notably the cockpit.
“The characteristics of the material deformation around the puncture holes appear to indicate that the objects originated from outside the fuselage,” says the inquiry. Analysis indicates that small objects entered from “above the level of the cockpit floor”, it adds.
Investigators state that the forward parts of the aircraft, including the cockpit, were found closest to the last position of MH17 captured on its flight-data recorder. This indicates that these sections broke off the 777 first. The central and aft structures were found “significantly” further east, showing that MH17 travelled forwards, descending, before breaking up.