What happened
During a positioning flight conducted under instrument meteorological conditions, the crew of a very light jet was cleared for an ILS approach. Although the tower controller had informed the crew that no standing water was present on the runway, the aircraft's approach speed was higher than recommended. Flight data records indicate the aircraft was traveling at 118 knots at 50 feet above the touchdown zone elevation, crossing the displaced threshold at 112 knots, and touching down at 104 knots with a 7-knot tailwind.
Shortly after the main landing gear made contact, the nose gear touched down, and the pilot applied the brakes. While the aircraft initially reached maximum deceleration through wheel braking, the crew expressed concern via the cockpit voice recorder that the plane was not slowing sufficiently. Approximately four seconds after reaching peak deceleration, the pilot engaged the emergency parking brake. This action caused the wheel speed to drop to zero and initiated a skid, leading to reverted-rubber hydroplaning. The aircraft subsequently overran the runway, crossed a service road, and ended up in a drainage ditch. There were 0 fatalities and 0 injuries reported.
Findings
Investigations into the braking system and brake control unit confirmed that the hardware functioned as intended. The aircraft lacked spoilers or thrust reversers to assist in deceleration. While the approach speed exceeded the operator's standard operating procedures and the aircraft's reference speed, calculations indicated the aircraft should have been able to stop on the available runway had the braking remained consistent.
The application of the emergency parking brake was a critical factor, as it induced a skid and hydroplaning that further degraded stopping performance. Additionally, while the runway was not officially contaminated with standing water, the observed braking friction was much lower than expected for a dry or merely wet runway, behaving more like a runway with standing water. It is believed the crew engaged the parking brake because they expected a higher rate of deceleration than the actual surface conditions allowed.