Shortly thereafter, the first officer noted and reported to the captain that they had already consumed half of their initial fuel load, although they had progressed to only their last waypoint "YNN" still inside Greece (about a third of the total distance to Vienna). At 12:34, the FMS prediction for fuel remaining upon arrival at Vienna fell to 1.9 t. Under such conditions, the airline rules require immediate diversion to the nearest suitable airport, which would have been Zagreb, 10 minutes away. The investigation report states "there was no evidence of immediate crew response to this situation." While contact with Zagreb ATC was made 9 minutes later, the crew pressed on towards Vienna, requesting the most direct access to a runway. At 12:53, the crew notified Vienna ATC that if direct runway access were not available, they would prefer to divert to closer Graz. This prompted Vienna ATC to inquire and finally learn that the flight was short of fuel, but the pilots declared no emergency, still anticipating a normal landing. When the fuel gauges fell through 1.9 t remaining, the first officer twice urged the captain to declare an emergency, but the captain postponed such action. At 13:01, the "LT-Fuel low level" warning indicated remaining fuel of 1340 kg, which automatically generates an ACARS message. At this time, the aircraft was northeast of Zagreb, south-east from Graz, and from the destination Vienna. At 11:07 UTC, the crew finally declared an emergency due to lack of fuel, while still stating that they expected to reach Vienna.