CEN21LA384 · Cirrus Design Corp SF50

The airport tower controller initially assigned the pilot to take off from runway 28L, which presented a 7-knot headwind. Shortly afterward, the controller informed the pilot of “a storm rolling in . . . from west to east,” and offered runway 10R. The pilot accepted the opposite direction runway for departure and added, “we’re ready to go when we get to the end . . . before the storm comes.” About 4 seconds after the airplane began accelerating during takeoff, the controller advised the pilot of a wind shear alert of plus 20 knots (kts) at a 1-mile final for runway 28L, and the pilot acknowledged the alert. In a postaccident statement, the pilot stated that departing with a 7-kt tailwind was within the operating and performance limitations of the airplane. The pilot reported that after a takeoff ground roll of about 4,000 ft “the left rudder didn’t seem to be functioning properly” and he decided to reject the takeoff. However, when he applied full braking, the airplane tended to turn to the right. He used minimal braking consistent with maintaining directional control of the airplane. The airplane ultimately overran the runway, impacted the airport perimeter fence, and encountered a ditch before it came to a rest. A postimpact fire ensued and consumed a majority of the fuselage. An examination of the runway revealed skid marks beginning about 4,700 ft from the arrival end of runway 10R. The initial set of skid marks were about 300 ft long. Skid marks resumed about 300 ft further down the runway and continued until they departed the left side of the pavement near the departure threshold. The skid marks associated with the left tire were consistent with heavy braking from the left main landing gear. The skid marks associated with the right tire were consistent with light braking from the right main landing gear. A postrecovery airframe examination did not reveal any anomalies consistent with a preimpact failure or malfunction. Data revealed that as the airplane began to accelerate during takeoff the airspeed lagged the ground speed, which was consistent with a tailwind condition at the time. The heading began to oscillate about the same time that the airspeed stagnated. During this time, the ground speed continued to increase consistent with an encounter with a tailwind gust. A few seconds later, the pilot initiated the rejected takeoff. About the time of the accident, the airport was impacted from the west by a gust front that caused low-level wind shear and surface winds increased from about 10 kts from the west-southwest to about 30 kts from the northwest. Weather forecasts and advisories in effect at the time of the accident noted the possibility of severe thunderstorms and strong wind gusts. The airport’s low-level wind shear alert system display, located in the control tower, presented numerous wind shear alerts applicable to the east side of the airport at the time of the accident takeoff. The tailwind gust likely reduced the effectiveness of the flight controls and resulted in the pilot’s perception that they were not functioning properly. In addition, the reduced flight control effectiveness, combined with the lack of nose wheel steering in the airplane model, resulted in a reduction of directional stability as evidenced by the heading oscillations. While the distinct runway skid marks indicated that the brakes were operating, the pilot was unable to stop on the remaining runway available.

Verbatim NTSB analysis and probable cause from the NTSB dataset