N427GECirrus Design SR20 · 2008

On March 11, 2013, at 1501 Pacific daylight time, a Cirrus SR20, N427GE, veered off the left side of the runway and into a ditch at the Kern Valley Airport, Kernville, California. The airplane was registered to East Pole Aviation, and operated by Justice Aviation under the provisions of 14 Code of Federal Regulations, Part 91. The private pilot and two passengers sustained minor injuries, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight originated at Bakersfield, California, about 1438.The pilot stated that while in the landing flare with the flaps configured full down, the airplane drifted right so that the right main landing gear was no longer over the runway. The pilot decided to execute a go-around. After he added power for the go-around, the left main wheel contacted the runway; the airplane veered left, continued off the left side of the runway, impacted a ditch, and came to rest inverted. The pilot indicated in the NTSB Pilot/Operator Accident Report (Form 6120.1) that there were no mechanical malfunctions or failures prior to the accident.

The Avidyne Primary Flight Display (PFD) was removed from the airplane and sent to the NTSB Vehicle Recorders Laboratory for data download and review. The Avidyne PFD unit includes a solid state Air Data and Attitude Heading Reference System (ADAHRS) and displays aircraft parameter data including altitude, airspeed, attitude, vertical speed, and heading. The PFD unit has external pitot/static inputs for altitude, airspeed, and vertical speed information. The PFD has a data logging function, which is used by the manufacturer for maintenance and diagnostics. Maintenance and diagnostic recordings consists of system information, event data, and flight data. The data extracted from the PFD contained the accident flight and other flights on March 11, 2013.

The following data was extracted from the Avidyne PFD for the accident sequence of events.

At 1501:24, the data indicated that the airplane's roll was 7 degrees left, the pitch was 2 degrees nose down, and the airspeed was 69 knots.

At 1501:28, the data indicated that the airplane's roll was 3 degrees right, the pitch was 5 degrees nose up, and the airspeed was 66 knots.

At 1501:30, the data indicated that the propeller rpm was 1,350, the airplane's roll was 2 degrees left, the pitch was 2 degrees nose up, and the airspeed was 62 knots.

At 1501:30 and 1501:36, the propeller rpm was 1,350 and 2,400, respectively. During this time period, the pitch, roll, and airspeed were sampled at a higher frequency. As such, determining when power was applied relative to pitch increase is limited by the sampling rate differences. However, during this period the pitch increased from 2 degrees nose up to 12 degrees nose up, the roll increased to 9 degrees left, the airspeed decreased to 56 knots, and by 1501:32, the longitudinal acceleration began to increase. Also during this period, the magnetic heading changed left from 351 degrees to 327 degrees.

At 1501:38, the pitch reached a maximum value of 17 degrees nose up when the airspeed was about 56 knots.

Between 1501:38 and 1501:41, the pitch decreased to 16 degrees nose down, and the aircraft rolled to 31 degrees right, before rolling back to the left through 20 degrees.

After 1501:41, the vertical acceleration increased to a full scale value of XYZ, the left roll angle increased to a full scale value of 180 degrees left, and the airspeed decreased to 0 knots.

The Cirrus SR20 Pilot Operating Handbook contains stall speeds for a gross weight of 3,000 pounds, flaps configuration, and angle of bank factors. The accident airplane configuration was flaps at 100% (full down), and for this configuration the stall speed at 15 degrees angle of bank is between 55-57 knots indicated airspeed (KIAS).

The Pilot Operating Handbook lists the following procedures for a Balked Landing/Go-Around.

1. Autopilot – Disengage

2. Power Lever – FULL FORWARD

3. Flaps – 50%

4. Airspeed – Best Angle of Climb (81-83 KIAS)

After clear of obstacles

5. Flaps – Up (0%)