Amateur-built TURBINE CUBS P A 18 N181TJ accident near Skull Valley, Utah

Probable cause

The activation of the wheel brakes during landing, which resulted in a nose-over. The reason for the wheel brake activation could not be determined.

NTSB analysis

The private pilot reported that he had just completed a low altitude pass and that when he applied power to initiate a climb, the engine "stumbled slightly and seemed to hesitate." The pilot applied carburetor heat due to concerns about carburetor ice and then applied full power. The engine again seemed to hesitate, and the pilot initiated a precautionary landing to an open salt flat. Shortly after touchdown, the airplane nosed over. The pilot reported that after he exited the airplane, he noted that both main wheel brakes were engaged, however neither he nor his passenger actuated the brake pedals during the landing sequence. A postaccident examination of the wheel brakes revealed no evidence of a preexisting malfunction or failure with the brakes.

Examination of the engine revealed that one of the two carburetor temperature probe wires were separated from an electrical connector, consistent with a bad crimp. The disconnected wire would have prevented the carburetor air temperature from being displayed on the airplane's avionics panel. The examination revealed no additional findings or evidence of a preexisting mechanical malfunction that would have precluded normal operation. The atmospheric conditions in the area at the time of the accident were conducive to the formation of carburetor ice at glide and cruise power. It is likely that the hesitation in the engine performance reported by the pilot was the initial stages of the accumulation of ice in the carburetor, which precipitated the off-airport precautionary landing.

Text from the NTSB. Open the NTSB docket for WPR18LA009 for the full record.