In particular , a hidden Hiding_objects indicator light led to Causation an operator manually overriding the automatic emergency cooling system of the reactor because the operator mistakenly believed Know that there was too much coolant water present in the reactor and causing Causation the steam pressure release .

The investigation Criminal_investigation could not determine Deciding the exact reason for the accident Catastrophe , but suspected Suspicion the insufficient meteorological information given Giving to the crew , failure of the ground equipment , and the atmospheric effects on the ADF indicator .

The primary cause Causation of the crash Catastrophe was that both pilots had lost Earnings_and_losses spatial orientation due to their inexperience with the Western type of attitude indicator on the aircraft .