The Brazilian air force reports it has begun operational testing of Embraer's KC-390 transport and tanker aircraft.

The first test earlier this month involved the dropping of paratroopers and was part of a test campaign to verify aerodynamic modifications made to the aircraft and to help define the aircraft's final configuration.

The testing includes the dropping of supplies and checks of the stability of extractor parachutes. The tests will continue until July 9.

"There were major concerns about the paratroopers' exit from the fuselage because there is an aerodynamic flow around a new airframe," said Col. Claudio Evangelista, the air force's technical manager of the KC-390 program. "Fortunately, the feedback we received from the military was very positive; they reported that the exit was very smooth."

The KC-390 is a medium-sized, twin-engine jet aircraft. It can carry as many as 80 passengers, and its cargo payload is 59,500 pounds.

The KC-390 conducted its first flight last year.

The Brazilian Air Force has ordered 28 of the planes.