A deadly midair collision between two small planes in Alaska over the weekend was marked by the same factor involved in another recent midair collision in the state — aircraft that were difficult to spot amid mountainous terrains, federal accident investigator said Monday.

The two crashes about 200 miles apart already are prompting plans to hold safety meetings with pilots on ways to see other aircraft and to be seen, said National Transportation Safety Board investigator Larry Lewis. He said depending on the weather, clouds can further camouflage planes.

"It is really difficult to spot another airplane that's airborne," particularly if it is flying at the same altitude, he said. "When you're looking at the same altitude, you're actually looking at very smallest cross section of an airplane you can actually see."

An Anchorage family of four died when their single-engine Cessna 180 floatplane crashed and burned Saturday after hitting the other floatplane north of Anchorage. Alaska State Troopers said they have tentative identifications of the dead but were not releasing names until the state medical examiner's office makes positive IDs.

Relatives confirmed those killed were the 41-year-old pilot, Corey Carlson, his 39-year-old wife, Hetty Carlson and their two daughters, 5-year-old Ella and 3-year-old Adelaide "Addie." The funeral for the four was scheduled for Aug. 12 at Our Lady of Guadalupe Parish in Anchorage, said Hetty Carlson's mother, Diane Barnett.

"It was a terrible accident," Barnett said, her voice breaking. "They were just an all-American family with some much to live for."

The other plane, a Cessna 206, sustained significant damage but was able to return to Anchorage. The 56-year-old pilot, Kevin Earp of Eagle River, was uninjured. Lewis interviewed Earp, a veteran Alaska Airlines pilot, telling him he saw the Cessna 180 at the last moment and was unable to avoid the collision.

The family in the Cessna 180 had planned to visit property in the Lake Clark area but the weather was so bad there, they decided to go north instead of west and visit another property at Amber Lake, according to Lewis. Earp also was headed there, and the two planes approached at right angles to each other.

It appears the Cessna 180 was preparing for a downwind landing at the lake when the collision occurred, according to Lewis, who is still investigating.

On July 10, nine people aboard a Piper Navajo and four people in a Cessna 206 were uninjured when the planes collided as they were flying directly toward each other in Lake Clark Pass — a narrow river valley that runs between Anchorage mountains. Both aircraft had minor damage but were able to land safely in Anchorage. In this collision, the planes overlapped each other by about 18 inches, Lewis said.

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

Even though the two midair collisions occurred just a few weeks apart, such accidents are not as common as the time span might suggest.

"There's a lot of airspace up there, and all they to be is 10 feet above each other or 10 feet below each other and they probably won't connect," Lewis said. "It takes a lot of factors to get a couple of airplanes together in midair."