Incident Overview

Description
The airline transport pilot was on an instrument flight rules (IFR) cross-country passenger flight under Title 14, CFR Part 135, when the accident occurred. According to the first officer, while on final approach, the “AUG/AIL” (aileron augmentation) light illuminated, indicating a system malfunction. He reset the system per the flight manual (FM), and the light went out. The approach was continued, but during landing, he reported that the AUG/AIL lamp illuminated again, and that the right wing dropped, striking the ground. The first officer said the captain, who was on the controls, had full left aileron deflection trying to compensate, without success. The airplane landed on runway 2C (center) with a magnetic runway heading of 020 degrees. The airport weather observation reported the wind as 310 degrees at 12 knots, with gusts to 17 knots. The first officer reported the wind as 310 degrees at 12 knots, with gusts to 19 knots. According to the FM, Wind Components Chart, an angle of 70 degrees between the prevailing wind direction and the runway heading, would produce crosswind components of 11 knots steady, and 16 knots during gusts for the reported airport observation. The corresponding wind components for the wind as reported by the first officer, would be 11 knots steady, with 18 knots during gusts. According to the FM, the maximum demonstrated crosswind component, when the wind is 90 degrees to the runway heading, is 24.7 knots. The FAA approved Master Minimum Equipment List limits the airplane to 20 knots maximum crosswind component with the AUG/AIL system inoperative. The AUG/AUL system is computer controlled, and automatically activates when the wing flaps are set below 25 degrees, using a combination of aileron and corresponding spoilers to enhance the airplane’s roll rate at low airspeeds. The airplane received structural damage to the right wing. An examination of the aileron augmentation system revealed an anomaly in the computer that controls the AUG/AIL system. When the computer was replaced, the system functioned normally. Probable Cause: The pilot’s inadequate compensation for gusty crosswind conditions during landing, which resulted in a loss of control and collision with the runway. Factors contributing to the accident were the failure of the aileron augmentation (spoiler) flight control system, diminished directional (roll) control, and crosswind gusts.
Primary Cause
Inadequate compensation for gusty crosswind conditions during landing, leading to loss of control and collision with the runway.Inadequate compensation for gusty crosswind conditions during landing, leading to loss of control and collision with the runway.Share on: