What happened
On a flight from Campbell River, British Columbia, to Renton, Washington, a float-equipped de Havillered DHC-2 Beaver, registration C-GCZA, was traveling in close proximity to a second Air Rainbow aircraft. As the two planes approached Samuel Island, visibility and cloud ceilings dropped significantly, prompting both pilots to seek a water landing to wait for better conditions.
After the lead aircraft landed and immediately took off again to overshoot the area, the pilot of C-GCZA attempted a similar maneuver. While performing this overshoot at approximately 80 mph with 15 to 20 degrees of flaps, the aircraft experienced an uncommanded left yaw. The pilot's attempt to correct this with the rudder resulted in a violent right yaw, causing the nose to drop into a steep, nose-down, left-wing-low attitude. The aircraft struck the water, causing substantial damage. While the pilot successfully evacuated the four passengers, the aircraft eventually capsized. There were no injuries reported.
The investigation
The investigation examined the flight operations, weather conditions, and the aircraft's aerodynamic characteristics. It was established that the pilot of C-GCZA had closed the distance to the lead aircraft, positioning his plane roughly 500 feet behind and 45 degrees off the wing. This proximity meant the actions of the lead aircraft directly influenced the trailing aircraft's flight path.
Investigators also reviewed the aircraft's weight and balance, noting it was within limits but positioned in the aft portion of the center-of-gravity envelope. Furthermore, the investigation looked into the aircraft's stall characteristics. While the DHC-2 was certified to provide aerodynamic warnings of an impending stall, the investigation found that the aircraft provided no clear indication of the approaching stall in this specific configuration.
Findings
- The pilot of C-GCZA reduced the spacing between the two aircraft, which allowed the lead aircraft's maneuvers to adversely affect his own.
- The aircraft stalled during an overshoot attempt while using insufficient engine power.
- The aircraft provided no warning of the impending stall through juddering or other aerodynamic means.
- The pilot's training had not provided exposure to the specific stall characteristics encountered when the aircraft is in an aft center-of-gravity configuration.
- The flight was conducted in marginal weather conditions that approached the limits of visual flight rules.