– A lack of guidance from the Federal Aviation Administration and improper training were significant factors in the midair collision of two sky diving planes over northwestern Wisconsin about two years ago, according to aviation investigators.

The National Transportation Safety Board has concluded its investigation into the November 2013 collision over Superior, Wis. All nine sky divers on the two planes and one pilot jumped to safety, while the other pilot landed a damaged plane.

The NTSB cited the FAA's lack of guidance on how pilots should fly formation flights with sky divers. Its investigation into the collision determined that the owner of the sky diving company did not provide sky diving formation flight training for its pilots, and did not keep records of pilot training, according to a report shared by Minnesota Public Radio News.

"If both pilots had received adequate sky diving formation flight training, they might have had a consensus about how the formation flight should have been flown," it said in its report.

Video footage from five helmet cameras shows one Cessna aircraft coming down on the back of another, shearing off the lead plane's right wing.

The pilots of each airplane had said they discussed prior to the flight how it would be flown. But in interviews with the NTSB, all three pilots described different expectations that they had for the separation between each plane.

Although none of the pilots said the trail airplane should be flown higher than the lead airplane, the video footage shows the trail airplane flying higher than the lead airplane before the collision.

Upon impact, pieces of the lead plane caught on fire, but everyone on both planes survived.

The sky divers who recorded the incident sold the footage for $100,000 to NBC News.