Diamond Aircraft Ind Inc DA 42 NG N621ZC and Piper PA 12 N7709H accident near Bozeman, Montana

Probable cause

The student pilot and flight instructor's failure to see and avoid the stationary airplane during taxi, which resulted in a ground collision.

NTSB analysis

The tailwheel-equipped airplane had completed a series of touch-and-go takeoffs and landings with the student pilot in the front seat and flight instructor in the rear seat. The airplane was equipped with large tundra tires which, in combination with the tailwheel configuration, provided limited forward visibility when on the ground.

The tower controller cleared the pilots to cross the landing runway, and then subsequently cleared the airplane across the parallel runway, which led it onto a taxiway where a low-wing airplane, having just cleared the parallel runway after landing, was stopped and preparing to contact ground control. Neither of the pilots onboard the tailwheel airplane saw the low-wing airplane before they collided with it on the taxiway, resulting in substantial damage to both airplanes.

The student pilot stated that he perceived that he should expedite the taxi across the parallel runway due to airplanes on approach to that runway, although review of air traffic control voice recordings revealed that the controller issued no instructions to expedite the taxi. Because of the faster taxi speed, the pilots did not perform any "S"-turn maneuvers to enhance forward visibility, which likely would have allowed them to see the low-wing airplane and prevented the collision.

Text from the NTSB. Open the NTSB docket for WPR18LA118 for the full record.