An Anchorage pilot and his family were the four people who died in a collision between their single-engine plane and another small aircraft, a co-worker of the pilot said Sunday.

The Cessna 180 was registered to Corey Carlson, a 41-year-old private pilot, who died with his wife, Hetty Carlson, 39, and their two young children, said Mark Mazur, who worked with Corey Carlson at GE Drilling Systems, an oilfield services company.

The crash around Amber Lake near Trapper Creek, 80 miles north of Anchorage, came nearly three weeks after another in-flight collision that remarkably left the 13 people aboard the two aircraft unhurt. In a vast state with a very limited road system, traveling by small plane is a common activity for many residents.

Alaska authorities had tentative identifications of the dead but were not releasing names until the state medical examiner's office makes positive IDs, said Megan Peters, a spokeswoman for state troopers.

Mazur said he learned of the deaths from Carlson's father, but he declined to say more.

Authorities said the floatplane crashed and burned after the collision with another single-engine floatplane, a Cessna 206, which suffered significant damage but was able to return to Anchorage.

The pilot, Kevin Earp, 56, of Eagle River, was alone in the aircraft and uninjured. There was no listing in Eagle River for Earp, and he did not respond Sunday to a message left through his son, Andrew Earp, in Fairbanks.

It's too early to speculate what caused the collision, said Larry Lewis, a National Transportation Safety Board investigator who was at the crash site Saturday evening.

"The airplane impacted the ground in a steep vertical descent," he told The Associated Press in an email Sunday. "Most of the airplane was consumed by a post-crash fire."

The bodies have been recovered.

On July 10, nine people aboard a Piper Navajo and four people in a Cessna 206 were uninjured when the planes collided. Both aircraft had minor damage but were able to land safely in Anchorage.

Federal Aviation Administration spokesman Mike Fergus described that incident as "almost unheard of."