An Adam Aircraft A700 very light jet built in conformity with the design the company expects to certify by the end of the year flew for the first time February 4. The successful flight, which took off from Denver's Centennial Airport, lasted 34 minutes and consisted of basic handling checks following a climb to 12,500 feet with gear down and flaps in takeoff configuration.
Test pilots Bill Watters, vice president of flight operations, and Ken Sasine, senior turbine test pilot, conducted two high-speed taxi tests to check the aircraft's ability to achieve rotation and found its characteristics similar to the non-conforming prototype A700, which had flown for nearly 400 hours since being introduced to the public during EAA AirVenture 2003. Satisfied with those preliminary runs, they departed Centennial for relatively brief tests of the aircraft's control forces and response to flap actuation from full up to 45 degrees down. While not surprised that the jet aircraft behaved as anticipated to flap extension and retraction, the crew was pleased to find control forces lighter than those of the prototype A700.
While aerodynamically identical to the prototype, the serial No. 2 jet features improvements in the engine nacelles to provide better access during preflight and maintenance. The Williams FJ33 turbofans are located 5 inches farther aft to meet rotor burst requirements. Changes were also made in the window placement and emergency exits. The baggage door for the nose compartment is larger, as are several access doors associated with routine maintenance. The aircraft features three Avidyne displays rather than two primary flight displays found on the prototype A700. Structurally, the serial No. 2 aircraft is stressed to accept a higher indicated speed and will be fitted with more powerful brakes, allowing the aircraft to achieve a maximum gross weight of 8,500 pounds, 1,500 pounds more than the A700 prototype.
Assuming no significant changes between the A700 used for certification flight testing and the serial No. 1 prototype, which we flew for the better part of an hour last Wednesday, pilots can expect the A700 to have impressive handling qualities in takeoff, climb, low-altitude cruise, and approach. The aircraft exhibited heavily damped responses to control inputs in pitch and yaw. In pitch, the aircraft's phugoid (the tendency for an aircraft to follow an ever decreasing up and down roller coaster motion when disturbed from its trim airspeed by either a gust or control input) was sufficiently damped so that oscillations subsided quickly. Such pitch characteristics result in good speed stability on approach and are favorable when attempting precise airspeed control. The aircraft's immediate response to a pitch control input was moderately crisp and well damped, a characteristic that contributes to good handing during the flare for landing as well as precise maneuvering in pitch.
Dutch roll, the side-to-side fishtailing that couples yawing and rolling motion when an aircraft encounters turbulence, also was heavily damped. Deflecting the rudder specifically to excite the Dutch roll resulted in typical yawing/rolling motions that subsided within less than two swings of the nose back and forth.
Roll characteristics were equally good. Spiral stability, the tendency for the aircraft to resist diverging into a descending spiral when a wing dips slightly, was impressive. When either wing was banked 10 degrees and then left unattended, the A700 maintained that degree of bank without added control action.
Serial No. 1 in the configuration we flew was not cleared for stalls. Our minimum speed was 100 KIAS. Approaches were flown at a reference speed of 105 kt with full (45 degrees) flaps. The aircraft tracked well on the ILS to Runway 35R at Centennial, and its trailing link landing gear and pitch characteristics allowed relatively smooth landings even with limited exposure to the A700.
Adam Aircraft appears to be entering the final year of its quest for a certificated very light jet. - John W. Olcott