After two rounds of discussions on YSR's chopper crash, the inquiry committee probing the incident has found crucial clues.

The former Andhra chief minister's helicopter was apparently being flown under the visual flying rule and not the instrument flying rules. The chopper crashed last Wednesday killing YS Reddy and four others on board.

Under the visual flying rule, the helicopter flies at a low altitude and for the ATC to track any change at that height is difficult.

This may limit the ATC's role in alerting the pilot about wind speed, direction and a generic forecast. The pilot generally flies using his own visual references.

Also under the visual flying rule, the ATC doesn't give instructions as it does to jet planes.

The last recorded conversation with the ATC shows that YSR's chopper was climbing to 5,500 feet. As of now, nothing beyond that is known about the communication between the pilot and the ATC.