Air force spokesman Col Jorge Amaral said earlier they were trying to reach the point from where the aircraft had last made contact, about 1, 200km (745 miles) north-east of Natal.
During the ascent of the giant balloon which will take Mr Baumgartner into the icy cold atmosphere and during the freefall, Col Kittinger's role will be to act as the point of contact between the mission control team and Felix Baumgartner.