Amateur-built KIT FOX IV 1200 N117S accident near St. Lucie, Florida

Probable cause

The pilot’s failure to maintain adequate airspeed during the turn to final, which resulted in an exceedance of the wing’s critical angle-of-attack and a subsequent aerodynamic stall. Contributing to the accident was the pilot’s combined use of two sedating antihistamines, which resulted in his impairment.

NTSB analysis

Witnesses reported that the airplane took off from runway 27, turned north, then circled back to a left downwind to land on the same runway. One witness noted that, during the downwind leg, the airplane was "very close in" to the runway and that, although the airplane had taken off in conditions that were a "little hazy," he subsequently saw the airplane "popping through clouds" on the downwind leg. Another witness reported that, during the airplane's turn toward the final approach to the runway, she saw the airplane's nose drop and then the airplane heading "straight down" before it disappeared behind a tree line. Multiple witnesses reported hearing the engine operating at a high-power level.

No preexisting mechanical anomalies were found that would have precluded normal operation. The airplane's close, downwind track and the wreckage location relative to the runway were consistent with a cross-controlled aerodynamic stall. However, the witness statement of the airplane's nose dropping straight down and the heading of the airplane at ground impact were more indicative of a straight (relatively balanced flight) aerodynamic stall.

Toxicology testing on the pilot detected low levels of the sedating antihistamine diphenhydramine and therapeutic levels of the sedating antihistamine doxylamine. The combination of the two drugs may increase side effects such as drowsiness, confusion, and memory problems, and the pilot's combined use of both drugs likely impaired his performance and contributed to the accident.

Text from the NTSB. Open the NTSB docket for ERA13FA201 for the full record.