History of Flight
On May 18, 2023, at approximately 0014 eastern daylight time, a Honda Aircraft Company HA-420, registration N225HJ, was substantially damaged when it overran the runway at Summerville Airport (DYB), Summerville, South Carolina. The commercial pilot and five passengers were not injured. The flight operated under Title 14 Code of Federal Regulations Part 91 as a personal flight.
The pilot and passengers were returning to DYB after attending a NASCAR race in Wilkesboro, North Carolina. The pilot stated he delayed the return to let rainstorms pass through the Summerville area and was aware he would be landing on a wet runway. The airplane departed Wilkes County Airport (UFK), North Wilkesboro, North Carolina, about 2329 on an instrument flight rules flight plan.
The pilot flew the RNAV RWY24 approach coupled to autopilot and took manual control around 600 ft above ground level. He calculated the approach reference speed (Vref) using the airplane’s control display unit (CDU) computer, which indicated 119 to 120 kts. He did not recall the required landing distance but stated the CDU indicated the 5,000-ft runway was sufficient.
The pilot flew the final approach at Vref of 120 kts with full flaps, touched down before the 1,000-ft markers, and immediately applied full brake pressure. The brakes cycled in anti-skid mode, which the pilot described as slower than normal, resulting in little braking effect. About halfway down the runway, the pilot realized he would not make his usual taxiway turnoff but was not concerned due to remaining runway.
The left brake then “grabbed” suddenly, causing a left yaw, followed by left and right skids. The pilot used rudder pedals to keep the airplane on the runway but it continued off the runway into the grass, slid down an embankment, and came to rest on a rocky berm about 360 ft from the departure end. The right wing caught fire, but all six occupants exited safely through the main cabin door.
Pilot Information
The pilot held a commercial pilot certificate with ratings for airplane single- and multi-engine land, and instrument airplane. His most recent FAA third-class medical certificate was issued July 22, 2022. He reported about 1,938 total flight hours, with about 233 hours in the HA-420. He last attended recurrent training for the HA-420 in December 2022 at Flight Safety International.
Aircraft and Wreckage Information
The airplane was equipped with a Garmin G3000 integrated flight deck. Due to thermal damage, no data were retrieved from the avionics units. A postaccident examination of Runway 24 revealed tire marks from the accident airplane landing gear, traced from the departure end back about 1,550 ft to taxiway C. The touchdown point could not be determined.
The airplane came to rest on a heading of about 240°. A post-impact fire consumed the cockpit, center fuselage, and right wing. The outboard section of the right wing separated; the majority of the right wing structure was consumed by fire. The left wing and No. 1 engine were largely undamaged. The nose landing gear separated and was found near the right empennage. The left main landing gear remained attached. Examination of tires showed no rubber reversion or indications of skidding.
Postaccident functional testing of brake assemblies, master cylinders, and other components revealed no anomalies except for the antiskid control unit and one master cylinder, which were thermally damaged and could not be tested. Initial testing of the power brake and antiskid valve showed an unexplained hysteresis, but subsequent testing at the original equipment manufacturer found no issues. The root cause of the initial behavior was not determined.
Meteorological and Airport Information
At 0015, weather at DYB reported calm wind, 6 statute miles visibility, mist, few clouds at 200 ft, broken clouds at 3,200 ft, overcast at 10,000 ft, temperature 21°C, dewpoint 21°C, and barometric altimeter setting 29.87 inHg.
DYB is a non-tower-controlled airport with a single asphalt runway, 6/24, 5,000 ft long by 75 ft wide, in excellent condition, crowned, not grooved, with a downhill gradient of about 0.03%.
Landing Performance Data
According to the HondaJet HA-420 Airplane Flight Manual (AFM), the prescribed landing distance for the accident flight was from the “Flaps LDG, Ice Protection Off” chart. This chart calculates Vref and landing distance on a dry runway. The AFM did not include wet runway tables but recommended increasing predicted landing distance by 30% for wet runways.
The pilot stated the landing weight was 9,647 lbs. Interpolation of the AFM table indicated a Vref of about 111 kts. The dry runway distance was about 3,500 ft, and the wet runway distance about 4,550 ft.
HondaJet personnel entered the accident flight conditions into an exemplar CDU, which calculated a Vref of 112 kts and a total landing distance of 4,829 ft. It could not be determined how the pilot achieved a Vref of 120 kts via the CDU. When a Vref increment of +5 and +10 kts was entered, the CDU calculated required landing distances on a wet runway as 5,311 ft and 5,794 ft, respectively, and displayed a “LANDING FIELD LENGTH INSUFFICIENT” caution.
In July 2022, HondaJet issued Service Bulletin 420-42-019 providing a Wet and Contaminated Runway Performance AFM Supplement and database installation. The accident airplane owner had not complied with this service bulletin, which was not mandatory for Part 91 operations. For aircraft without the supplement, pilots used the 30% wet runway distance increase, which for the accident flight would have required about 6,100 ft, exceeding the available runway length.
No cockpit voice or flight data recorder was installed, nor required. ADS-B data showed the airplane’s last recorded position at 200 ft above the runway at 120 kts ground speed and 119 kts calibrated airspeed.