Considering how rare single-seat twins are outside the military, it’s remarkable how little information about N72TZ can be found on the Internet. The NTSB’s report on the fatal outcome of its first flight provides scant detail about the airplane itself. It seems, from bits and pieces mined here and there, to have been one of a kind, designed by a homebuilder, to have had a gross weight of 800 pounds and to have been powered by two two-stroke Hirth engines, each developing 28 hp at 6,500 rpm and driving fixed-pitch propellers, possibly through cog-belt speed-reduction systems.
Two photographs of N72TZ can be found, seemingly taken moments apart. It was a sleek, attractive airplane, painted a deep claret color, with sinuous lines — the sort of airplane amateur designers love to sketch. Its general arrangement resembled that of the three-surface Piaggio Avanti, with a T-tail, a small canard and pusher engines set inboard on the wings. Its ground attitude appears to have been a bit nose-low, like that of many jets. From its shadow — the sun stood more or less at the zenith when the photographs were taken — one can see that the areas of its three surfaces, relative to one another, were roughly similar to those of the Avanti. It was shorter-coupled, however, and the mainplane was located approximately amidships, whereas that of the Avanti is farther from the canard.
The creator of N72TZ had previously built a Lancair Legacy and was a commercial multi- and instrument-rated pilot with more than 2,000 hours. It is unclear whether he had any formal training or experience in aeronautical engineering — but many successful airplanes have come from self-taught amateur designers.
The airplane had been issued a special airworthiness certificate on July 2, 2009. Initial taxi testing had revealed a lack of pitch authority; even at 55 knots, the pilot could not get the nosewheel off the ground. Accordingly, two changes were made: The canard elevator was enlarged by an unspecified amount, and ballast was added to move the CG “aft of 30 percent of mean aerodynamic chord.” These changes had the desired result: It was now possible to rotate the airplane at 45 to 50 knots. During a later series of high-speed taxi tests, the pilot “routinely raised the nose of the airplane.”
N72TZ was equipped with a Dynon electronic flight information system that recorded a number of parameters, including airspeed, altitude and pitch attitude, at one-second intervals and made it possible for accident investigators to reconstruct its first and final flight in some detail. The accident, which took place on Sept. 24, was preceded by a high-speed taxi test during which the EFIS recorded a maximum speed of 67 knots and a pitch angle of 9 degrees — not necessarily at the same moment.
On the next run, the airplane became airborne — whether intentionally or not we don’t know. It rapidly pitched up 45 degrees, zoomed more than 120 feet above the runway, turned to the right, stalled, lost airspeed, pitched down and fell, hitting the ground in a roughly level attitude. The pilot-designer-builder, 62, died after the crash.
The airplane was not fragmented. Investigators established continuity in the flight and engine controls, and witnesses reported that the engines had run throughout the brief flight. The NTSB accordingly concluded that the probable cause of the accident was “the pilot’s failure to maintain pitch control of the airplane.” It did not speculate about the reason.
