Accident Overview
On August 9, 2024, at approximately 1750 Pacific daylight time, a Cirrus Design Corp. SF50, registration N727VB, was substantially damaged during a landing accident at Watsonville Municipal Airport (WVI) in Watsonville, California. The pilot and one passenger were not injured. The flight was operated under Title 14 Code of Federal Regulations Part 91 as a business flight.
Flight Details
According to the pilot, the flight departed Ogden-Hinkley Airport (OGD) in Ogden, Utah, destined for Watsonville. The enroute portion was uneventful. Upon arrival, the pilot configured the airplane for landing by extending the landing gear, confirming three green indications on the multi-function display (MFD), and setting flaps to 100%. The airplane touched down at approximately 80 to 85 knots, and the landing was described as normal, with no bounce or period of only one main gear on the runway. When the pilot began applying brakes, the nose landing gear collapsed. The pilot cycled the landing gear handle (raised then lowered) without effect on the collapsed nose gear, and maintained directional control until the airplane came to a stop. Postflight inspection revealed substantial damage to the composite fuselage undercarriage near the nose gear bay.
Data from the aircraft's Central Management Computer (CMC), recorded at one-second intervals, was reviewed along with ADS-B data. At 1250:28, when the airplane was about 1,250 feet from the runway threshold, the flaps were at 100%, the gear handle indicated down, and all three landing gear were down and locked. Fourteen seconds later, the airplane touched down, as indicated by left and right wheel speeds increasing from 0 to about 1501 rpm and 1488 rpm, respectively. One second later, weight-on-wheels (WOW) data indicated a load on both main landing gear. Two seconds later, WOW data indicated no load, the gear handle remained down, and the landing gear were down and locked. At 1250:47, the gear handle indicated up, WOW switches indicated no load, the main gear indicated down but not locked, the nose gear indicated down and locked, and the hydraulic pack was enabled with the gear directed up. One second later, the nose gear also indicated down but not locked, the left WOW switch indicated no load, the right WOW switch indicated a load, and the hydraulic pack remained enabled. At 1250:49, the gear handle indicated down, the nose gear indicated not down and not locked, the main landing gear indicated down but not locked, the hydraulic pump was enabled, and the gear was not directed up. The airplane indicated a 12.5° nose-down attitude. From 1250:50 to 1250:54, the gear handle indicated neither up nor down, before returning to the down position.
A review of CMC data from the previous twelve flights showed that flap retraction from 100% to 0% occurred between 2 and 70 seconds after touchdown, with eight out of ten retractions occurring within 2 to 5 seconds. On the accident flight, no flap retraction was recorded.
Post-Accident Examination
A postaccident examination of the airframe and landing gear revealed that one of the two nose landing gear (NLG) locking springs was missing from the nose gear assembly. According to the manufacturer, the NLG locking springs are installed to assist the gear into the locked position during alternate/freefall extension, and the second spring is for redundancy. A functional test of the landing gear, with the airplane stabilized on floor jacks and a tail stand, found no preaccident mechanical malfunctions or failures that would have precluded normal operation. Maintenance records indicated that the airplane underwent an annual inspection on April 10, 2024, which included a check of the landing gear, with no anomalies noted.
Pilot Information
The pilot reported a total of 4,300 flight hours, including 443.4 hours in the SF50. In the last 90 days, the pilot had logged 102.5 hours in the SF50; in the last 30 days, 50.9 hours; and in the last 24 hours, 4.0 hours.