Accident Details
On a visual flight rules flight from Campbell River, British Columbia, to a logging camp on Mackenzie Sound, a de Havilland DHC-2 Beaver floatplane (registration C-GVHT, serial number 257) took off at 1530 Pacific daylight time. The aircraft carried a pilot and four passengers. The scheduled arrival time was 1700.
Upon arriving 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. Citing unfavourable weather conditions, he announced his intention to return, presumably to Campbell River. The aircraft then flew to a clear area north of the camp and entered the Frederic Creek valley.
When company ground personnel could not contact the aircraft, they initiated a ground search, later supplemented by an aerial search. Poor weather hampered search efforts. Three days later, the aircraft wreckage was discovered approximately four nautical miles northeast of the camp. The accident occurred at 1706 in daylight conditions. All occupants sustained fatal injuries, and the aircraft was destroyed. The emergency locator transmitter was destroyed on impact and did not transmit a signal. No fire occurred.
Probable Cause
The official investigation identified the following findings as to causes and contributing factors: 1. The pilot abandoned his attempt to fly through the pass because of unsuitable weather conditions. He flew into a confined area that required him to manoeuvre the aircraft aggressively to avoid the rising terrain, causing the aircraft to stall. 2. The aircraft weight exceeded the certificated maximum allowable gross weight, and the center of gravity was outside the floatplane aft limit. The out-of-limit weight and balance aggravated aerodynamic stall and produced rapid and uncontrolled aircraft attitudes from which the pilot could not recover before striking the trees. 3. Basic weight and balance of the aircraft was incorrectly recorded in several aircraft documents, leading to remarkable discrepancies in take-off weight and center of gravity calculations. As a result, a pilot could not calculate an accurate weight and balance. In certain conditions, calculations erroneously showed that the aircraft was below maximum allowable gross weight.
Findings as to risk included: the use of non-standard passenger weight leading to inaccurate take-off weight calculations; weight and balance calculations using inaccurate figures would not have revealed overloading until approximately 450 pounds beyond the maximum limit; the aircraft's weight and balance placed it outside the manufacturer's design envelope; and cargo was not secured and might have shifted during manoeuvring, exacerbating aft CG effects and increasing injury levels.
Other findings noted that the pilot chose to fly above cloud in accordance with visual flight rules and could not descend through cloud at the intended landing site; the Alaska cargo door installation increases cargo volume conducive to overloading; and the DHC-2 Beaver lacks an aural or visual stall warning system, relying on aerodynamic indications.