Federal investigators have recovered a cockpit voice recorder from the air tanker that crashed in Utah and killed two pilots fighting a wildfire.

The recorder survived the crash intact and was sent for analysis to a Washington, D.C., lab, National Transportation Safety Board supervisor Debra Eckrote said Friday.

NTSB investigator Van McKenny also recovered a black box that monitors engine performance, but Eckrote said that box was damaged and may not yield useful data.

The tanker was reduced by Sunday's crash on a mountain slope to fragments that revealed few clues about the crash, she said.

That makes the cockpit voice recorder all the more important in determining a cause.

"It looked to be in good condition. Cockpit voice recorders can withstand very severe forces," said Eckrote, a deputy regional NTSB chief in Seattle.

In Washington, D.C., NTSB spokesman Nicholas Worrell said Friday that the voice recorder had arrived at the lab. He said he didn't have any information about its contents.