CEN21FA130 · Velocity Vtwin

The two pilots were conducting a cross-country ferry flight under a special flight permit in the experimental, twin-engine, pusher configuration airplane. The purpose of the flight was to relocate the airplane to have maintenance performed on the landing gear system. The provisions of the special flight permit indicated that the airplane be operated with the retractable landing gear extended and authorized a co-pilot even though the airplane did not require more than one crewmember.

Just after departure on the second leg of the flight, the pilot reported an engine issue to the tower controller and stated that they wanted to return to the airport but did not require any assistance. He was instructed by the controller to report turning final to the runway, an instruction he acknowledged. There was no further communication from the pilot. The controller reported that he saw the airplane just before impact in a turn consistent with maneuvering for landing when its bank angle increased until he lost sight of it behind trees. The airplane impacted trees and came to rest inverted in a river about 1 mile south of the airport, with substantial damage to the fuselage, both wings, and both canards.

Data recovered from onboard avionics and a performance study indicated that, about the same time as the pilot reported the engine problem, the airplane’s climb performance decreased similar to flight on a single engine. Indicated airspeed increased to about 16 knots above the maximum airspeed for flight with the landing gear extended (VLE), consistent with a transition from a climb pitch attitude to a level pitch attitude. Data from the onboard avionics indicated a loss of right engine power about 1 minute later, and the airplane entered a descent that continued until impact. Data from the left engine were not recorded.

The right main landing gear door separated from the airplane and was not located. Additionally, all three propeller blades from the right engine separated about 18” outboard from the propeller hub, and only one was recovered. Both the left and right engine remaining propeller sections appeared in the feathered position at the accident site. The left engine oil pressure sending unit wiring harness contained broken wires that were not consistent with impact damage. The left throttle, propeller, and mixture cockpit controls were found in a further aft position than the right controls, consistent with an intentional engine shutdown.

Based on the available information, it is likely that the damaged wiring harness resulted in the pilots receiving a red “X” on the primary flight display left engine oil pressure indication. This likely prompted the pilot’s initial call to the tower controller of an engine anomaly and the subsequent precautionary shutdown of the left engine.

As the pilots continued back toward the runway and accelerated the airplane past VLE, the right main landing gear door likely departed the airplane and impacted the right propeller, as evidenced by impact damage to the metal leading edge of the recovered propeller blade, consistent with screw or bolt threads This impact resulted in a total loss of right engine power. With both engines inoperative, the airplane likely did not have the energy available to glide back to the runway.

Recovered onboard data from the previous flight revealed that the airplane had been operated well above VLE, despite the ferry permit limitation. It is possible that the right landing gear door attachment points may have been weakened by the higher air loads associated with airspeeds exceeding VLE on the previous flight and the accident flight, as well as higher-than-normal sideslip angles that would have been required with the left engine shut down.

Toxicology testing of the left seat pilot revealed the presence of potentially impairing medications; however, whether the effects of the medications or underlying medical conditions contributed to the accident could not be determined. Although it is likely that the right seat pilot was acting as pilot-in-command, since he had previously flown the accident airplane; the pilot flying at the time of the accident could not be determined based on the available information.

Verbatim NTSB analysis and probable cause from the NTSB dataset