Embraer EMB-500 N661EP accident near Jacksonville, Florida

Probable cause

The flight crew’s failure to apply maximum braking immediately upon touchdown, which resulted in a runway excursion. Contributing to the accident were 1) the slightly excessive approach airspeed and 2) the flight crew’s decision to land on a wet runway during heavy rain with little margin between the unfactored landing distance required and the landing distance available.

NTSB analysis

The flight crew performed an instrument landing system approach in heavy rain. The published unfactored landing distance, which assumes ideal conditions for airplane speed, flightpath, and maximum braking immediately after touchdown, was about 330 ft shorter than the landing distance available. The factored landing distance, which 1) provides a safety margin and 2) allows for some variance from the ideal conditions, was about 1,360 ft longer than the landing distance available. During the approach, when the airplane was about 50 ft above the runway, the airspeed was about 4 knots higher than the target speed.

After touchdown, the pilot(s) began braking within 1-2 seconds; however, the brake pedals did not reach their maximum braking position until about 8 seconds after touchdown. The brake pedals remained in the maximum position for 3 seconds before the parking/emergency brake was applied. The parking brake activation, which is not protected by the anti-skid system, resulted in the locking of both main landing gear wheelsets, reducing braking performance significantly. As a consequence of the wheels locking, the anti-skid system was deactivated, as designed. The airplane departed the end of the runway at a speed of about 60 knots and sustained substantial damage.

Text from the NTSB. Open the NTSB docket for ERA21LA077 for the full record.