Amateur-built GLASAIR III N39RD accident near Austin, Texas

Probable cause

The pilot’s use of an improper attitude and airspeed during landing followed by excessive braking, which resulted in the airplane wheelbarrowing on the runway and a subsequent loss of directional control.

NTSB analysis

The pilot reported that he landed the airplane with about 5 knots of extra airspeed in case he encountered a surface crosswind. The airplane touched down about 6 ft right of the runway centerline. Shortly after touchdown, the nosewheel began to shimmy violently. The pilot applied maximum braking to both pedals simultaneously to reduce the speed as he applied back stick pressure, but the nosewheel continued to shimmy. The nosewheel fork then failed, and the nose landing gear dug into the runway, which caused the airplane to veer off the right side of the runway. The nose landing gear collapsed in the soft ground, and the airplane subsequently nosed over. The postaccident examination of the nose landing gear, shimmy damper, and nosewheel revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

The examination of the runway revealed a skid mark produced by the nosewheel tire, which indicated that the tire skidded back and forth while the airplane's direction continued straight down the runway. According to Federal Aviation Administration guidance, wheelbarrowing occurs when a pilot permits the airplane weight to become concentrated about the nosewheel during takeoff or landing, which can cause of a loss of directional control. One of the most common causes of wheelbarrowing during the landing roll is the simultaneous touchdown of the main wheels and nosewheel with excessive speed. The guidance states that "heavy braking should be avoided until the wings are devoid of lift and the airplane's full weight is resting on the landing gear," which is contrary to the pilot's actions. The circumstances of the accident were consistent with the airplane wheelbarrowing during the landing.

Text from the NTSB. Open the NTSB docket for CEN14LA497 for the full record.