The pilot was the only person aboard the helicopter, according to the California Department of Forestry and Fire Protection.
The Bell UH-1H helicopter was carrying out a mission on the Hills Fire, near the city of Coalinga, Fresno County when it collapsed.
The identity of the pilot has not been revealed yet. The reasons for the crash are being investigated, the department added.
Previously, tens of thousands of Californians were forced to flee their homes in the North Bay area as a result of intensifying wildfires spreading across the state.
According to California Governor Gavin Newsom, there are more than 360 known fires currently burning in California. The US state is undergoing record heat levels and has seen more than 10,000 lightning strikes in the last 72 hours.