Accident Overview
On November 15, 2014, at approximately 1420 Pacific standard time, a Cessna U206G, registered as N9420R, veered off the runway during the landing roll at Brackett Field Airport (POC) in La Verne, California. The aircraft was owned and operated by the Civil Air Patrol under 14 Code of Federal Regulations Part 91. The private pilot and two passengers were not injured. The airplane sustained substantial damage to the right wing. Visual meteorological conditions prevailed, and no flight plan had been filed. The instructional flight had departed from San Gabriel Valley Airport in El Monte, California, about 1350.
Pilot and Passenger Accounts
During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge, the pilot reported difficulties controlling the airplane after the nose wheel settled onto the runway during the landing roll. He stated that the airplane initially veered left, but he was able to counteract the deviation, positioning the airplane near the right side of the runway. Subsequently, the airplane veered left a second time, and he could not prevent it from exiting the runway surface. After leaving the runway, the right wing struck the ground.
The two passengers stated that the landing appeared normal, but shortly afterward, the pilot lost directional control of the airplane.
Postaccident Examination
A postaccident examination was conducted with a certified airframe and powerplant mechanic under NTSB supervision. The right wing was found bent upward about 3 feet from the wing tip. The airplane's braking continuity from the rudder pedals to the brakes was established with no anomalies. Examination of the nose tire, main tires, and braking assemblies revealed no issues. The nose gear assembly was inspected, and the nose oleo strut was observed to be deflated. However, when weight was applied to the nose wheel by lifting the airplane's tail, the nose wheel responded appropriately to pedal steering. The investigation could not determine whether the deflated strut resulted from impact damage or a preexisting malfunction. No other mechanical malfunctions or failures that would have precluded normal operation were found.
Nose Wheel Steering System
The airplane's nose wheel steering system connects the rudder pedals to the nose wheel. According to the Pilot's Operating Manual, depressing a rudder pedal activates a spring-loaded bungee that turns the nose wheel approximately 15 degrees each side of center. Applying left or right brake can increase the turn angle up to 35 degrees each side of center.
The aircraft manufacturer representative explained that a steerable nose wheel mounted in a fork attached to an air/oil (oleo) shock strut constitutes the nose gear. Nose wheel steering is accomplished via rudder pedals. A hydraulic fluid-filled shimmy dampener minimizes nose wheel shimmy. Torque links keep the lower strut aligned with the steering system while permitting shock strut action. A properly serviced nose gear oleo fully extends when the nose wheel is lifted off the ground. A centering stop lug on the upper torque link engages a cutout near the top of the oleo when fully extended, preventing nose gear movement during rudder pedal actuation. When the oleo is compressed, the centering stop lug disengages, allowing the nose wheel to respond to rudder pedal inputs.