Primary finding
Probable cause
Loss of control during the landing roll due to a malfunctioning brake for undetermined reasons.
Investigator assessment
Analysis narrative
The pilot reported that during the landing roll, he applied the brakes to slow down; however, the left brake did not function properly, and the airplane veered to the right of the runway. The pilot attempted aerodynamic braking and used full left rudder in an attempt to return the airplane to the runway centerline. The airplane continued to the right down an embankment, nosed over, and came to rest inverted. Review of accident site photographs showed impressions from all three-landing gear in the dirt adjacent to the runway, with the right landing gear showing a more pronounced indentation in the dirt. due to heavy braking on the right side it is likely the right brake locked up. A postaccident examination of the brakes revealed improper retaining bolts securing the brake calipers; however, both brakes functioned normally. No other mechanical anomalies were found that would have precluded normal operation.
Source record
Factual narrative
On January 18, 2024, about 1240 Pacific standard time, a Cessna 172L, N7250Q, was substantially damaged when it was involved in an accident near Grass Valley, California. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that his flight to Nevada County Airport (GOO), Grass Valley, and the subsequent approach and touchdown were normal. During the landing roll on runway 25, as he applied the brakes to slow down and exit the runway, the airplane veered to the right. The pilot stated that the left brake did not function. The airplane slowed to less than 35 mph as it traveled past the taxiway turn . The pilot stated that the engine was at an idle power setting, and he attempted the use of aerodynamic braking to stop the airplane, which he believed would stop before the end of the runway. The pilot stated that he “got off the brakes,” and attempted to correct back to runway centerline with the application of full left rudder pedal. The airplane continued to veer to the right, exited the right side of the runway, traveled over an embankment, and came to rest inverted. The airplane sustained substantial damage to the wings, vertical stabilizer, rudder, and propeller. A review of photographs provided by the Federal Aviation Administration, showed that all three-landing gear had left impressions in the soft dirt adjacent to the runway. The right main landing gear impression exhibited a more pronounced indention mark in the dirt than the left main and nose landing gears. A postaccident examination of the brake system revealed improper retaining hardware bolts securing the backplates of the left and right brake calipers. Both brakes were manipulated by the rudder pedals and when activated were “firm” and functioned normally. Examination of the nose landing gear oleo strut showed the torque links were not contacting the centering block on the strut housing. The left and right steer rods were attached and had continuity with the left and right rudder pedals.