BOULDER COUNTY, Colo. (KDVR) – Two planes crashed mid-air in Longmont Saturday morning leaving three pilots dead.

According to the Boulder County Communications Center, they received reports of a mid-air collision involving two planes around 8:53 a.m. on Saturday.

“It looked like it was in trouble, cause planes don’t go straight down. There was no fireball, nothing, it just crumpled,” said Sean Tufts, who called 911 after watching one of the planes crash.

Other neighbors in the area described the moment the planes collided.

“We get plane traffic here a lot on a weekend morning so it’s not unusual. But, we heard a pop then got a text from my neighbor saying he saw the planes hit and crash right on Niwot,” said Cary Hayes, who lives across the street from where one of the planes went down.

“It’s scary. It’s super scary. It happened right across the street from my house,” Hayes said.

Mountain View Fire Rescue said that crews arrived at the site of the plane crash located at 10111 Niwot Rd. around 10 a.m. Shortly thereafter, they determined a second plane was involved.

“It took us a little while to find it cause it’s in the trees behind us,” David Beebe, Fire Chief of the Mountain View Fire Protection District, said.

The Boulder County Sheriff’s Office confirmed that three people had died from the collision.

According to the National Transportation Safety Board, the two planes involved were a Cessna 172 and a Sonex Xenos.

NTSB said the Cessna aircraft was flown by two pilots, one was a flight instructor and another a student pilot. Both were declared dead at the scene.

The second plane was found in the 9700 block of Niwot Road. The sole pilot was also declared dead at the scene.

“These skies are full all day with single-seater planes,” Tufts said.

NTSB provided an update on their investigation into the cause of the collision.

Tracking data showed the two pilots flying the Cessna aircraft departed on a training flight from the Rocky Mountain Airport at 8:43 a.m. The pilot in the Sonex aircraft departed from the Platte Valley Airpark in Hudson at 8:38 a.m.

During its flight, the Cessna made a 360-degree left turn and then a right turn to the east. According to NTSB, at that moment the two aircraft’s flight tracks merged and both descended rapidly in a rural area.

NTSB confirmed the weather was good for flying and pilots had clear skies.

Neither aircraft was equipped with a collision avoidance system that would have alerted the pilots to other aircraft in the area, and neither aircraft was in contact with air traffic control. According to NTSB, the aircraft were not required to do either.

The identities of all involved have not been released.

BCSO said that this investigation is still in the early stages. NTSB said they will release their preliminary reports in about two weeks.

If you witnessed this crash, please contact Detective Galloway by calling 303-441-4763. Witnesses can also report information to NTSB on their website.