For a second time, W.W. “Bill” Boisture, the CEO of Beechcraft Corp. (formerly Hawker Beechcraft), is challenging the U.S. Air Force's decision to award a contract to Sierra Nevada Corp. to supply 20 Embraer A-29B Super Tucano aircraft for the Light Air Support (LAS) program for use by the Afghan military.

Boisture claims the Defense Department is spending significantly more for the A-29B than it would for Beechcraft's AT-6, its proposed LAS variant of the T-6 Texan II turboprop primary trainer. The T-6 is a well-proven platform, and the AT-6 shares about 80% of its parts.

I could see Boisture's point if lowest cost were the only criterion for awarding a contract and if the AT-6 and A-29B offered equivalent capabilities. But neither point is the case.

I have flown both aircraft and there are significant differences. The AT-6 is a trainer that has been adapted for the LAS role with a 1,600-shp engine, a beefed-up wing with hard points, plus twin external gun pods, an electro-optical/infrared camera sensor ball and a network-centric C2ISR communications suite, among other significant improvements. On paper, that gives the AT-6 virtually the same capabilities as the A-29B Super Tucano.

Walk around the two aircraft, though, and obvious differences emerge. Built from the ground up for the light attack role, the Brazilian contender is considerably larger than the Beechcraft. The relatively small five-blade propeller offers 5 in. more ground clearance than the AT-6's four-blade prop, and its oil cooler intake is much higher, for protection against foreign object damage. These features make the Super Tucano better suited to rough-field operations.

The A-29B's wingspan is 4 ft. wider than the AT-6's and the lateral distance between the landing gear is 50% greater, making the aircraft easier to handle on runways in stiff crosswinds. The A-29B's main landing gear rolling stock is larger, featuring low-pressure 6.5-10 tires that are better suited to unimproved runway operations than the AT-6's high-pressure, 4.4-20 tires that are designed for smooth pavement. The A-29B's fuselage is 3 ft. longer and its vertical stabilizer is 2.3 ft. higher, providing more aerodynamic stability to handle the 1,600-shp engine.

The Super Tucano, to be assembled in Jacksonville, Fla., has two internally mounted 250-round FN Herstal .50-caliber guns plus four wing-mounted hard points for external stores and a center-line fuselage station for an external fuel tank. It can carry 3,420 lb. of external stores with fully loaded guns.

The AT-6 has six wing hard points, two of which can accommodate 400-round FN Herstal .50-caliber gun pods. While the AT-6 carries more ammunition, internal guns are easier to keep boresight-aligned than external gun pods. And the AT-6's external stores load is limited to 2,675 lb. with fully loaded gun pods.

Belt into the front seat of each aircraft and more important differences emerge. The A-29B's canopy is considerably larger, affording better visibility in the combat environment. Front and rear internal windshields protect the crew if the canopy is lost in combat. Its sensor ball is mounted farther forward on the bottom of the fuselage so its view of targets abeam the aircraft is not blocked by the wing when the aircraft is banked. The larger wing affords more lateral control with asymmetric external stores loads, such as a pilot might encounter if a 500-lb. smart bomb hangs up on an ejector rack.

The A-29B also has anti-skid power brakes, a computer that calculates drag and runway distance for 133 different external stores configurations and an autopilot that can be coupled to the mission computer to reduce pilot workload. The aircraft also has a proven combat record, having logged more than 18,000 hr., mainly in counterinsurgency operations against the Revolutionary Armed Forces of Colombia (FARC). It has amassed about 180,000 hr. with the air forces of Brazil, Chile, Colombia and Ecuador. Deliveries now have begun to Angola and Indonesia.

But, even if the two aircraft were exactly comparable, the long-term financial staying power of the two companies is not the same. That is a key risk factor written into the Federal Acquisition Regulation decision-making process. Sierra Nevada and Embraer have strong product portfolios and robust balance sheets. They will assemble the Super Tucano in Jacksonville. Beechcraft, having shed several unviable product lines, just now is emerging from bankruptcy. The Wichita manufacturer still faces a tough road to recovery. So, on balance, I believe the Air Force twice made the best choice for LAS, first in December 2011 and again in 2013.

Tap on the icon in the digital edition of AW&ST for more on the LAS procurement saga, including Fred George's pilot reports on the AT-6B and Super Tucano, or go to AviationWeek.com/las