A 2016 midair collision near Russian Mission that left five men dead was ultimately the result of pilot error according to federal investigators, who urge aviators to fit planes with transmitters and displays so they can track each other.

The collision near the Western Alaska village, between a Cessna 208 Caravan operated by Hageland Aviation and a Piper Super Cub operated by Renfro’s Alaskan Adventures, took place on Aug. 31, 2016. All three people in the Caravan – pilot Harry Wrase, 48, and passengers Steven Andrew, 32, and Aaron Minock, 21 – as well as Super Cub pilot Justin Babat, 44, and passenger Jeff Burruss, 40, lost their lives.

The National Transportation Safety Board issued its final reports Wednesday on the two planes involved, attributing the deadly wreck's probable cause to “the failure of both pilots to see and avoid each other while in level cruise flight, which resulted in a midair collision.”

The scene of an Aug. 31, 2016 midair collision near Russian Mission that left five people dead, seen in National Transportation Safety Board imagery. (From NTSB)

“Given the remote area in which the airplanes were operating, it is likely that the pilots had relaxed their vigilance in looking for traffic,” NTSB officials wrote.

The Caravan had taken off three minutes before the 10:01 a.m. collision en route from Russian Mission to Marshall, according to the NTSB, while the Super Cub had left Bethel shortly after 9 a.m. headed for a hunting camp about 20 miles north of Russian Mission.

Investigators wrote in Wednesday’s report that they found signs in the planes’ wreckage “consistent with the Cessna's outboard left wing initially impacting the Piper's right wing forward strut while in level cruise flight.”

“Examination revealed no mechanical malfunctions or anomalies that would have precluded normal operation of either airplane,” NTSB officials wrote. “Neither pilot was in communication with an air traffic control facility and they were not required to be.”

The scene of an Aug. 31, 2016 midair collision near Russian Mission that left five people dead, seen in National Transportation Safety Board imagery. (From NTSB)

Responders drove to the crash site in all-terrain vehicles and the Alaska Army National Guard sent a rescue helicopter, but there were no survivors.

Federal Aviation Administration regulations placed the area of the crash under its “see and avoid” doctrine, which requires pilots to watch for and steer away from other aircraft, although research indicates the average physiological and mechanical lag time to do so is 12.5 seconds. The NTSB report notes that “the see-and-avoid concept requires vigilance at all times by each pilot, regardless of whether the flight is conducted under instrument flight rules or [visual flight rules].”

Although the collision occurred amid sunny and clear skies, the report noted that until about 10 seconds before impact, the pilots would have seen each others’ planes as “a relatively small, slow-moving object” roughly the diameter of a penny viewed from 7 feet away. In the seconds before the collision, however, the planes would “blossom” in each other’s view.

“From about 2 minutes before the collision, neither airplane would have been obscured from the other airplane pilot's (nominal) field of view by cockpit structure, although the Cessna would have appeared close to the bottom of the Piper's right wing and near the forward edge of its forward wing strut,” NTSB investigators wrote.

The scene of an Aug. 31, 2016 midair collision near Russian Mission that left five people dead, seen in National Transportation Safety Board imagery. (From NTSB)

The Caravan carried an Automatic Dependent Surveillance-Broadcast (ADS-B) transmitter, which broadcast its location to other aircraft. Neither plane in the collision, however, was fitted with a cockpit display of traffic information (CDTI) which would have showed planes’ locations or courses.

“CDTI data would have presented visual information regarding the potential conflict to both pilots beginning about 2 minutes 39 seconds and auditory information beginning about 39 seconds before the collision, providing adequate time for the pilots to react,” NTSB investigators wrote.

The NTSB also found a similar probable cause to the Russian Mission crash, in its final reports Wednesday on another Alaska midair collision that same month. Two people suffered minor injuries in the Aug. 5, 2016 incident at the Wasilla Airport, where two planes collided as they were both attempting to land.

Mike Hodges, the NTSB investigator who examined both collisions, said they offer important lessons to Alaskan aviators.

“I think the two big takeaways are number one, a midair collision can happen anywhere in the country whether it’s congested airspace or remote airspace,” Hodges said. “And number two, the see-and-avoid concept doesn’t work – and the only way to protect yourself is to have an ADS-B system.”

The FAA is still rolling out formal ADS-B requirements for aircraft types and regions, Hodges said, so the systems aren’t yet required on all U.S. aircraft.

According to Hodges, the disparity of the two Alaska midairs’ locations show that watching for other aircraft is a statewide concern.

“I think people have the perception that a midair collision would happen over Anchorage or someplace where there’s a lot of people, but Russian Mission proved that it can happen anywhere,” Hodges said. “Pilots have to be vigilant – whether they’re flying over Anchorage or Russian Mission, they have to be vigilant at all times.”

Copyright 2019 KTVA. All rights reserved.