Incident Overview
A corporate flight carrying a pilot, copilot, flight attendant, and six passengers departed for a private airstrip. After leveling off at flight level 280, the flight crew checked weather conditions at nearby airports. Based on the information, the pilot planned for a visual approach to the runway.
Approach and Landing
As the airplane neared the destination, the pilot flew over the runway and entered a left downwind visual traffic pattern to check for animals on the runway and to observe the windsock. The pilot reported not seeing the windsock during the flyover. Turbulence and wind gusts from the hills below and to the west were noted. When the airplane was over the runway at about 50 feet above ground level (agl), the pilot reduced engine power to idle. The pilot then reported encountering wind shear; the airspeed dropped rapidly, and the airplane was forced down onto the runway. A representative at the airstrip reported a hard landing.
Post-Impact Sequence
After touchdown, the pilot unlocked the thrust reversers, applied brakes, and reached to deploy ground spoilers. As the thrust reversers deployed, the pilot felt as though the right landing gear had collapsed. He applied full left rudder and aileron, but the airplane continued to veer right. Attempts to steer left using the tiller produced no response. The airplane departed the side of the runway into the grass, resulting in substantial damage. The right main landing gear was broken aft and collapsed under the right wing.
Examination and Weather Data
Postaccident examinations of the airplane revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. A review of weather conditions showed surface winds from the north to northwest at 15 knots, with gusts up to 20 knots. There was potential for turbulence and wind shear below 5,000 feet, though no direct observations were available. The area forecast about 30 minutes after the accident called for northwesterly winds at 10 to 17 knots with a few higher gusts in the afternoon for the general area.
EGPWS Data
Data from the onboard enhanced ground proximity warning system (EGPWS) revealed that the crew received a terrain alert just before the airplane crossed the runway threshold. At the time the airplane was over the runway threshold, it was 48 feet agl and descending at a rate of 1,391 feet per minute. The airplane impacted the runway three seconds later.
Conclusion
Given the pilot's account, the weather information for the area, and the data from the airplane's EGPWS, it is likely that the airplane encountered wind shear while transitioning from approach to landing.