Flight Details
A de Havilland DHC-2 Beaver floatplane, registration C-GVHT (serial number 257), departed Campbell River, British Columbia, at 1530 Pacific daylight time with a pilot and four passengers. The aircraft was on a visual flight rules flight to a logging camp on Mackenzie Sound, 76 nautical miles northwest of Campbell River, scheduled to arrive at 1700. The aircraft made a brief intermediate stop at Hoeya in Knight Inlet before continuing.
Accident Sequence
Upon arrival over the Mackenzie logging camp, the pilot radioed ground personnel that he was overhead at 2800 feet between cloud layers with no place to descend and that due to unfavorable weather, he was returning to Campbell River. The aircraft then flew to a clear area north of the camp and entered the Frederic Creek valley. When ground personnel could not contact the aircraft, searches began and the wreckage was found three days later about four nautical miles northeast of the camp. The accident occurred at 1706 in daylight conditions. All occupants were fatally injured, and the aircraft was destroyed. The emergency locator transmitter was destroyed on impact; no fire occurred.
Terrain and Weather Conditions
At the time, the ceiling over the camp (sea level) was between 1600 and 1700 feet. The north end of the south Frederic Creek valley was free of cloud, but cloud was moving through a pass into the valley at the south end. The pilot declared he intended to assess the weather in the pass. The rising terrain and cloud base limited the aircraft's height above ground, and the valley narrowed toward the south end. The pass required an east-west crossing, making it impossible to see through until the aircraft was in it.
Maneuvering and Stall
Wreckage damage and tree damage indicate the aircraft followed a steep, nose-down flight path seconds before impact. It struck trees and came to rest inverted, likely rolling inverted when the pilot lost control. The accident occurred after a left turn away from the pass during the second attempt to get through. The turn radius was smaller and speed slower than in the first circuit. It is most likely that during the second attempt, the pilot slowed the aircraft and, when aborting, turned sharply to avoid higher terrain, forcing a left turn in a confined area with greater bank angle.
Weight and Balance Issues
The aircraft weight exceeded the certificated maximum allowable take-off weight (MAUW), and the center of gravity (CG) was outside the floatplane aft limit. Incorrect values were used for aircraft basic weight and passenger weight (errors of 275 and 185 pounds respectively), leading to weight and balance calculations being approximately 450 pounds less than actual. The out-of-limit condition aggravated the aircraft's response to the evasive maneuver, resulting in an abrupt attitude change from which the pilot could not recover before losing control and striking trees. The stall and loss of control occurred seconds before impact.
Cargo and Additional Factors
The Alaska cargo door installation increased cargo compartment volume, conducive to larger loads stowed farther aft, possibly overloading the compartment. Unrestrained cargo likely shifted during maneuvering, exacerbating the out-of-limit CG. Heavier cargo items could become projectiles during impact, increasing injury level, but impact forces were not survivable. No mechanical conditions were identified as contributing.
Findings
The pilot abandoned his attempt to fly through the pass due to unsuitable weather and flew into a confined area requiring aggressive maneuvering, causing a stall. The aircraft weight exceeded MAUW and CG was outside the aft limit, aggravating the stall and preventing recovery. Basic weight and balance were incorrectly recorded, preventing accurate calculations. The use of non-standard passenger weight led to inaccurate take-off weight calculations.