HISTORY OF FLIGHTOn July 9, 2021, about 2051 Pacific daylight time, an experimental amateur-built North Wing Mustang 3 weight-shift-control trike, which was not registered, was substantially damaged when it was involved in an accident near Millersburg, Oregon. The noncertificated pilot and passenger were fatally injured. The aircraft was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to family members, the pilot and passenger departed from the pilot’s home airport in Albany, Oregon. After overflying the pilot’s home, located about 4,000 ft north of the airport, the aircraft continued northeast for about 3.3 miles. The aircraft then turned left and flew close to the passenger’s home before impacting the ground (see figure 1).
Figure 1. Likely flightpath impact
Several witnesses on the ground recorded the airplane’s maneuvers on their mobile phone devices. A review of those videos showed that the aircraft banked to the left in an almost 90° turn. The left wing continued to drop downward, and the aircraft descended toward the ground as the turn tightened. The aircraft impacted terrain in a left-wing-low attitude (see figure 2).
Figure 2. Excerpts from a mobile phone video. PERSONNEL INFORMATIONThe pilot, who owned the trike, did not hold a pilot certificate, and his flight experience is unknown. AIRCRAFT INFORMATIONThe experimental light-sport, weight-shift-control aircraft had tricycle landing gear and a braced fabric wing. The two-place tandem cockpit frame was constructed of welded steel framing with a fiberglass cockpit fairing encompassing the frame. The wing was manufactured on December 8, 2015, and had a maximum gross weight of 1,060 pounds. The aircraft had stall speed at gross weight of 37 mph, a maximum speed of 62 mph, and a never-exceed speed of 70 mph. The aircraft’s limitations included not exceeding bank angles of 60° and pitch angles of 30°. The aircraft’s tachometer indicated the engine had a total time of 287 hours.
According to the North Wing Mustang 3-15 Wing Manual,
No wing on the market is totally safe. It is entirely possible to push any aircraft beyond its tolerances and damage or even break a wing. Very strong weather conditions may also cause structural failure. Aerobatics maneuvers, pitch angles beyond 30 degrees up or down, bank angles exceeding 60 degrees, aggressive stalls, and spins are maneuvers that should never be attempted under any circumstance.
CAUTION The speed never to exceed for the MUSTANG 3-15 is 70 mph. The MUSTANG 3-15, even when flown in its lightest wing loading, can exceed [an] airspeed of 70 mph.” AIRPORT INFORMATIONThe experimental light-sport, weight-shift-control aircraft had tricycle landing gear and a braced fabric wing. The two-place tandem cockpit frame was constructed of welded steel framing with a fiberglass cockpit fairing encompassing the frame. The wing was manufactured on December 8, 2015, and had a maximum gross weight of 1,060 pounds. The aircraft had stall speed at gross weight of 37 mph, a maximum speed of 62 mph, and a never-exceed speed of 70 mph. The aircraft’s limitations included not exceeding bank angles of 60° and pitch angles of 30°. The aircraft’s tachometer indicated the engine had a total time of 287 hours.
According to the North Wing Mustang 3-15 Wing Manual,
No wing on the market is totally safe. It is entirely possible to push any aircraft beyond its tolerances and damage or even break a wing. Very strong weather conditions may also cause structural failure. Aerobatics maneuvers, pitch angles beyond 30 degrees up or down, bank angles exceeding 60 degrees, aggressive stalls, and spins are maneuvers that should never be attempted under any circumstance.
CAUTION The speed never to exceed for the MUSTANG 3-15 is 70 mph. The MUSTANG 3-15, even when flown in its lightest wing loading, can exceed [an] airspeed of 70 mph.” WRECKAGE AND IMPACT INFORMATIONOn-site examination of the aircraft, including the flight controls, structure, and engine, revealed no evidence of any mechanical anomalies. Grounds scars and the orientation of the wreckage were consistent with the aircraft impacting the ground in a nose-low attitude. No manufacturing anomalies were noted with the aircraft. The wooden propeller assembly was shattered and exhibited signatures consistent with the engine producing power at the time of impact. Individual wires were separated at the nose; the wires were examined by the National Transportation Safety Board’s Materials Laboratory, which determined that the wires had fractured in overstress. The pilot’s family stated that a postaccident engine examination found no evidence of a preimpact mechanical malfunction or failure. ADDITIONAL INFORMATIONA video study was performed on the captured imagery to estimate the aircraft’s ground track, groundspeed, altitude, and roll angle. The estimated groundspeed when the aircraft initiated a left turn was 60 ± 3 mph (52 ± 3 knots). The altitude above ground level was 233 ± 10 ft at that time. The left-wing-down roll angle increased to almost 90º about 6 seconds after the turn was initiated. The aircraft impacted the ground about 9 seconds afterward. The engine speed was within its normal range, and the aircraft roll angle was increasing at a high rate.