ERA23FA138 · Diamond Aircraft IND Inc DA 40

The right-seat pilot, who held a flight instructor certificate, and the left-seat pilot, who held a private pilot certificate, arrived at the destination airport in night visual meteorological conditions. Two witnesses who were at the airport waiting to meet the accident pilots reported that the airplane descended on final approach to 20 to 30 ft above the runway. They then observed a go-around, which the pilots did not announce on the airport’s common traffic advisory frequency (CTAF). The witnesses reported that the airplane flew above the runway and did not climb any higher than 200 to 250 ft above ground level. Upon reaching the departure end of the runway, the airplane banked to the right, stalled, and rolled inverted before impacting the ground. The witnesses did not report hearing any engine discrepancy during the approach or go-around, but one witness reported the engine did not seem to the operating at full power during the go-around. Videos of the airplane taken by one of the witnesses captured a portion of the go-around and the moments just before the accident. Analysis of the videos determined that the engine rpm was about 2,400 before the right turn, after which engine rpm decreased slightly to around 2,300. Examination of the airplane revealed that the wing flaps were retracted, and there was no preimpact failure or malfunction of the flight controls. Examination of the engine powertrain, air induction, exhaust, and ignition systems revealed no evidence of preimpact failure or malfunction. One fuel injector nozzle and an attached fuel line was separated from its cylinder; however, this was likely the result of impact damage. The witnesses did not report anything unusual about the approach that would have required a go-around, nor was there any communication from the pilots on the CTAF or to either witness about a go-around. It is possible that the go-around and subsequent low pass were performed for the benefit of the witnesses, who were known by at least one occupant of the airplane to be waiting for the airplane’s arrival. Although the engine was operating just below full power before the in-flight loss of control, and the throttle control was found separated, the throttle control system was equipped with a spring that would have moved the throttle control full forward in the event of separation of the throttle control cable. Thus, the reduced power setting was likely an intentional setting by the pilots rather than a separation of the throttle control cable or an engine malfunction. Toxicology testing revealed that the left-seat pilot had used a product containing delta-8-THC, which has the potential to alter perception and cause impairment; however, the measured delta-8-THC levels in his cavity blood and urine could not be used to determine whether or to what degree he may have experienced associated impairing effects. With the non-psychoactive metabolite of delta- 9-THC detected, and no delta-9-TCH or psychoactive metabolite of delta-9-THC detected, it is unlikely that delta-9-THC use contributed to the accident. While the flight instructor did not hold an FAA medical certificate, no significant natural disease was found at autopsy and there was no evidence that his previously reported obstructive sleep apnea contributed to the accident. The circumstances of the accident are consistent with the pilots’ exceedance of the airplane’s critical angle of attack while maneuvering after a go-around/low pass, which resulted in an aerodynamic stall, loss of control, and impact with terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset