Primary finding
Probable cause
The pilot's failure to maintain directional control during takeoff, which resulted in a runway excursion.
Investigator assessment
Analysis narrative
The pilot of the tailwheel equipped biplane reported that during the takeoff sequence of a touch-and-go landing he decided to try a 2-point takeoff. He further reported that he was aware of the left turning tendency when raising the tail, however the "left turning factor happened much faster than [he] anticipated"; he was unable to recover with full right rudder inputs and the biplane veered to the left off the runway. During the runway excursion, the pilot brought the throttle to idle and the biplane impacted tumbleweeds. The biplane sustained substantial damage to both right wings. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. Federal Aviation Administration's Airplane Flying Handbook, FAA-H-8083-3B (2016), contains a section titled "Normal Takeoff Roll" for tailwheel airplanes which states: It is important to note that nose-down pitch movement produces left yaw, the result of gyroscopic precession created by the propeller. The amount of force created by this precession is directly related to the rate the propeller axis is tilted when the tail is raised, so it is best to avoid an abrupt pitch change. Whether smooth or abrupt, the need to react to this yaw with rudder inputs emphasizes the increased directional demands common to tailwheel airplanes, a demand likely to be unanticipated by pilots transitioning from nosewheel models.
Source record
Factual narrative
The pilot of the tailwheel equipped biplane reported that during the takeoff sequence of a touch-and-go landing he decided to try a 2-point takeoff. He further reported that he was aware of the left turning tendency when raising the tail, however the "left turning factor happened much faster than [he] anticipated"; he was unable to recover with full right rudder inputs and the biplane veered to the left off the runway. During the runway excursion, the pilot brought the throttle to idle and the biplane impacted tumbleweeds. The biplane sustained substantial damage to both right wings. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. Federal Aviation Administration's Airplane Flying Handbook, FAA-H-8083-3B (2016), contains a section titled "Normal Takeoff Roll" for tailwheel airplanes which states: It is important to note that nose-down pitch movement produces left yaw, the result of gyroscopic precession created by the propeller. The amount of force created by this precession is directly related to the rate the propeller axis is tilted when the tail is raised, so it is best to avoid an abrupt pitch change. Whether smooth or abrupt, the need to react to this yaw with rudder inputs emphasizes the increased directional demands common to tailwheel airplanes, a demand likely to be unanticipated by pilots transitioning from nosewheel models.