Improper landing speed and distance calculations by the pilot caused a HondaJet HA-420 to overrun a wet runway at Summerville Airport (KDYB) in South Carolina on May 18, 2023, according to the NTSB’s final report. The pilot and five passengers were uninjured, but the aircraft was substantially damaged after it ran off the end of the runway, slid down an embankment, and caught fire.
Registered as N255HJ, the aircraft departed Wilkes County Airport (KUKF) at 11:29 p.m. on an IFR flight and landed at KDYB around 12:14 a.m. in night visual conditions on a wet, 5,000-foot asphalt runway. The pilot told investigators he had used the aircraft’s cockpit display unit (CDU) to calculate a landing reference speed (Vref) of 119 to 120 knots and believed the runway length was sufficient.
ADS-B data showed the aircraft crossing the runway threshold at 120 knots ground speed and 119 knots calibrated airspeed. However, based on the weather and landing weight, HondaJet engineers later determined that the correct Vref should have been approximately 112 knots, and that the landing distance required on a wet runway was about 4,829 feet. A CDU programmed for those conditions would have issued a warning: “LANDING FIELD LENGTH INSUFFICIENT.”
The HondaJet touched down before the 1,000-foot markers. The pilot reported full brake application, but said the antiskid system cycled more slowly than usual, producing minimal braking. He considered aborting the landing, but a sudden “grab” from the left brake caused the aircraft to yaw and skid. The aircraft exited the end of the runway, descended an embankment, and came to rest on a rocky berm 360 feet beyond the pavement. A post-impact fire consumed the cockpit, center fuselage, and right wing, but all occupants exited safely.
A post-accident inspection found no evidence of pre-impact braking system failures. However, a test anomaly involving the power brake and antiskid valve showed unexplained hysteresis, or a lag between input and result, when first examined on a non-certified bench setup. Subsequent testing at the manufacturer’s certified facility revealed no anomalies. While significant hysteresis “may lead to braking performance degradation,” the NTSB concluded there was insufficient evidence to link the valve behavior to the accident.
At the time of the accident, the operator had not installed the 2022 HondaJet updated software and performance data for wet and contaminated runway operations. Although this supplement was free and recommended, compliance was not mandatory under Part 91.
The aircraft was not equipped with a cockpit voice or flight data recorder, nor was one required. Investigators reconstructed the accident timeline using ADS-B and witness statements.