The commission determined that the accident had been the fault of the Kazakhstani Il-76 commander, who (according to FDR evidence) had descended from the assigned altitude of and subsequently and even lower. The report ascribed the cause of this serious breach in operating procedure to the lack of English language skills on the part of the Kazakhstani aircraft pilots; they were relying entirely on their radio operator for communications with the ATC. The radio operator did not have his own flight instrumentation and had to look over the pilots' shoulders for a reading. Kazakhstani officials stated that the aircraft had descended while their pilots were fighting turbulence inside a bank of cumulus clouds.