A helicopter supporting efforts to contain Yosemite National Park’s Dome Fire crashed on Sunday, September 20, killing both crew members aboard. Precision, the aircraft’s operator, confirmed the deaths and expressed grief for the families and colleagues affected.

According to the Federal Aviation Administration, the Eurocopter AS32 went down in Mariposa County at approximately 2:55 p.m. The aircraft was assisting firefighters in controlling the blaze.

The National Transportation Safety Board is expected to lead the crash investigation, with assistance from the FAA. The cause has not been established.

Precision asked for privacy and compassion as the victims’ families and the company’s team mourned.

The accident occurred during the response to a wildfire that began on September 15. By Monday, September 21, the Dome Fire had burned more than 3,000 acres and was reported to be 15% contained.

Firefighters were encountering different conditions as the flames moved through previously burned terrain. CAL FIRE said some affected areas included land burned by the 2017 Empire Fire, where reduced vegetation was helping limit fire activity.

In those areas, the blaze largely crept along the ground and smoldered. However, windblown embers continued to create spot fires north of the main fire, complicating containment efforts.

The firefighting response and aviation investigation remained ongoing.