Two crew members killed in firefighting helicopter crash in Yosemite

Two crew members died Sunday when a firefighting helicopter crashed in California's Yosemite National Park while working a wildfire.

The aircraft, a Eurocopter AS332L1 Super Puma, was making water bucket drops on the blaze when it went down at about 3 p.m. local time.

As of Monday afternoon, authorities had not named the two people who died. The National Transportation Safety Board is leading the investigation.

The helicopter was flown by Fly Precision, an aviation company headquartered in McMinnville, Oregon, whose services include firefighting, aircraft maintenance, charters and unmanned drones. In a statement posted on its website, the company said it was sharing news of the loss of two team members with "unimaginable sadness and broken hearts," adding that it was devastated and asking for privacy for the families and staff.

The crew had been assigned to the Dome Fire, which has burned in a remote section of the park since the previous week. A U.S. Forest Service spokesperson said the fire cannot be reached by ground-based motorized vehicles, leaving crews to hike in with hand tools and depend on aerial support. It has burned more than 3,023 acres near the Wawona Campground area and is about 15 percent contained.