Accident Overview
On May 15, 2021, at approximately 2115 central daylight time, a Cirrus SR22, registration N4144B, was involved in an accident near Whitewater, Wisconsin. The aircraft, operated as a personal flight under Title 14 Code of Federal Regulations Part 91, sustained substantial damage. The pilot and passengers were not injured.
Pilot's Account
According to the pilot, the flight was conducted under instrument flight rules. During the flight, the pilot began to receive conflicting information from the flight instruments and the digital flight information display. Specifically, the turn coordinator and GPS displayed opposite information, the heading bug moved erratically, and the pilot felt as if the airplane was flying in circles. After determining that the flight instruments could not be relied upon, the pilot elected to activate the Cirrus Airframe Parachute System (CAPS). The airplane subsequently came to rest in a stand of 60-foot-tall trees, resulting in substantial damage.
Equipment
The airplane was equipped with a Sandel SN3308 electronic horizontal situation indicator (EHSI), a Mid-Continent 4305-150 directional gyro, a BF Goodrich Aerospace horizon reference indicator, and the pilot was using ForeFlight on a personal tablet.
Postaccident Examination
A postaccident examination of the airplane revealed no pre-impact mechanical anomalies that would have precluded normal operation. External power was supplied to the airplane, and all instruments powered up normally. The airplane was positioned on a movable dolly cart, allowing manipulation to verify instrument functionality. The turn coordinator operated as designed when the empennage was moved, as did the horizon reference indicator. The EHSI powered up but displayed a configuration error; however, the remote gyro wire harness wires were cut during recovery, and the flux detector was disconnected.
Instrument Testing
The EHSI, directional gyro, and horizon reference indicator were removed and subsequently tested. The EHSI was connected to an automated tester that evaluated inputs and outputs; the unit passed all tests. The directional gyro was connected to 28V DC power; the heading was steady and did not drift. The unit passed all testing except counterclockwise heading stability—the limit was ±2°, but the unit measured +5°. When shut down, the rotor coasted for over 9 minutes, consistent with a free and stable rotor. The horizon reference indicator was connected to an external power source and allowed time to steady the gyro. After caging the gyro, the unit was pitched up and down, and rolled left and right; it responded as designed through all movements. Power was removed, and the gyro coasted to a stop, consistent with a free gyro.