This diagram provides a direct comparison of the A-29 Super Tucano and the AT-6 prototype. While the AT-6 was upgraded to the same 1,600 shaft horse power Pratt and Whitney PT6 engine utilized by the A-29 (though with no corresponding change to the control surfaces), that is where the similarities stop.
At first glance you can see that the A-29 Super Tucano is a significantly larger aircraft than the AT-6. It also sits higher off the ground. The A-29‘s size and height advantage are coupled with ultra-rugged landing gear that have a broad stance -- greater distance between the wheels. This makes the A-29 more stable in rugged terrain than the AT-6.
Another important design advantage is the A-29’s stepped tandem cockpit. This characteristic means greater rear seat visibility, providing improved safety and mission effectiveness.
From a handling and growth perspective, the A-29 provides both superior fly-ability and greater “real estate.” Why? Beacause, the A-29 has a longer empennage, or tail section, which increases longitudinal stability and is the cornerstone of the A-29's exceptional bombing accuracy. Further, the A-29 has significant room to grow with regard to integration of future ISR equipment, communications gear, and weapons.
Another key difference between the two aircraft is the A-29’s internally-mounted .50 caliber machine guns. The AT-6 carries no weapons in it’s native configuration and therefore must give up a vital “hard point” under each wing for a gun pod, exacting a penalty in both payload and performance.
ISR capability is another key requirement. In the case of the A-29 Super Tucano, a fully-integrated EO/IR imaging system is positioned under the nose of the plane for maximum effect. Due to a lack of space and balance, the AT-6 places its thermal imaging system under the cockpit, which leads to degraded effectiveness whenever the plane drops a wing to turn.