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Last updated: 7 December 2021
Status:Final
Date:Thursday 5 June 2003
Time:18:00
Type:Silhouette image of generic DHC6 model; specific model in this crash may look slightly different
de Havilland Canada DHC-6 Twin Otter 300
Operator:Ontario Ministry of Natural Resources
Registration: C-GOGC
MSN: 750
First flight: 1981
Engines: 2 Pratt & Whitney Canada PT6A-27
Crew:Fatalities: 0 / Occupants: 1
Passengers:Fatalities: 0 / Occupants: 0
Total:Fatalities: 0 / Occupants: 1
Aircraft damage: Damaged beyond repair
Location:Lake Wicksteed, ON (   Canada)
Phase: Maneuvering (MNV)
Nature:Fire fighting
Departure airport:Hornepayne Airport, ON (YHN/CYHN), Canada
Destination airport:Hornepayne Airport, ON (YHN/CYHN), Canada
Narrative:
The DHC-6-300 amphibious aircraft was performing firefighting operations in the vicinity of Lake Wicksteed. The aircraft was scooping water from Lake Wicksteed for the nearby fire. This was the third scooping from the lake, and the approach was flown in an easterly direction in light wind conditions. The pilot performed the inbound checks, lowered the water probes to begin filling the float water tanks, and touched down on the lake. Within a short time, he observed water spraying from the overflow vents located on top of the floats, indicating that the tanks were filled to capacity. He pressed a button on the yoke to retract the probes, and the aircraft immediately nosed over into the lake in a wings-level attitude and began to sink. The aircraft came to rest on the bottom of the shallow lake in an inverted attitude with the floats above the surface of the water.

Probable Cause:

FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. Ministry of Natural Resources DHC-6 SOPs were not followed, and the Vital Action checklist was not fully completed during the approach. As a result, the bomb door armed switch on the centre panel was not selected OFF after the previous water bombing run and prior to the scooping operation.
2. After completing the water scooping operation, the pilot unintentionally selected the bomb door push button switch instead of the adjacent probe switch. Because the bomb door armed switch on the centre panel was left ON, the bomb doors extended into the water. Drag from the doors and the water rushing into the door openings resulted in the aircraft nosing over in the water.
3. The hinged cover plate for the bomb door push button switch was not re-installed following maintenance to replace the push button switch. The push button was exposed, making an inadvertent selection more likely.

Accident investigation:
cover
Investigating agency: TSB Canada
Status: Investigation completed
Duration: 10 months
Accident number: TSB Report A03O0135
Download report: Final report

Sources:
» Air International (October 2003, p.19)


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This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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