Bill Yearwood, the investigator in charge with the Transportation Safety Board, said the accident involved a single engine amphibious water bomber.
"The 'Fire Boss' water bomber ran into some trouble while scooping water at Puntzi lake," said Yearwood. "The aircraft subsequently sank."
He said the pilot was able to escape with minimal injuries.
Kevin Skrepnek with the B.C Wildfire Management Branch said the pilot has been brought to hospital for further observation.
The 1,200 hectare fire in the province's Cariboo district was discovered on July 8 and is currently not contained at all.