What aircraft was involved and where did it happen?

The accident on 2004-04-08 involved a Mount O'Leary, British Columbia, operated by Cirrus Design SR20 C-GEMC, at CA.

What was the probable cause of the accident?

The aircraft entered an unrecoverable spiral dive after an uncommanded 90-degree roll occurred while the autopilot was engaged, for reasons that remain undetermined.

Cirrus SR20 parachute deployment following mid-flight roll

A Cirrus SR20 experienced an uncommanded 90-degree roll during a night flight in British Columbia, leading to a spiral dive and emergency parachute deployment.

What happened

On a night VFR flight from Kelowna, British Columbia, to Lethbridge, Alberta, a Cirrus SR20, registration C-GEMC, entered a critical flight state while climbing through 880-foot altitude. The flight, which had originated in Seattle, Washington, was carrying the pilot and three passengers. During the initial climb, the aircraft exhibited a tendency to veer sharply to the left on two separate occasions, prompting the pilot to adjust fuel tank selection to balance the wings.

Upon reaching a cruising altitude of 9500 feet with the autopilot engaged, the aircraft suddenly rolled 90 degrees to the left. The pilot disconnected the autopilot in an attempt to regain control, but the aircraft entered an unrecoverable spiral dive. In response, the pilot shut down the engine and deployed the Cirrus airframe parachute system (CAPS). The aircraft subsequently came to rest in a remote area near Edgewood, British Columbia.

The investigation

Investigators examined the wreckage after it was airlifted to a secure site. The aircraft sustained significant damage to its underside, including a broken nosewheel leg and a damaged engine crankshaft caused by propeller contact with the ground. While the autopilot and flight instruments were tested and found to be functioning normally, the elevator trim was discovered in the full nose-down position.

Weight and balance calculations revealed that the aircraft had been operating outside of its manufacturer-established envelope. During the departure from Seattle, the aircraft was approximately 235 pounds over the maximum allowable take-off weight, and during the departure from Kelowna, it was 60 pounds over the limit. However, at the time of the actual occurrence, the aircraft was within its allowable weight and center of gravity limits.

Findings

The aircraft rolled 90 degrees to the left while the autopilot was engaged for undetermined reasons, resulting in a loss of control.
The aircraft was operated overweight during its departures from both Seattle and Kelowna.
The emergency locator transmitter (ELT) failed to activate because the impact forces were insufficient to trigger the device, and the pilot did not manually activate it following the parachute deployment.
The successful deployment of the CAPS likely prevented zero fatalities among the four occupants.