Search underway in Colorado when plane goes missing after takeoff from airport

Authorities searched early Monday morning for a missing single-engine, fixed-wing aircraft that was last detected near Eldorado Springs after takeoff from the Vance Brand Airport in Longmont on Sunday night. According to investigators in Boulder County, the plane was believed to have taken off from the airport about 6:30 p.m.

The Boulder County Sheriff's Office said during a news conference on Monday morning that the Air Force Rescue Coordination Center received an alert about a possible downed aircraft at 9:42 p.m. Sunday. Shortly after, an emergency transponder beacon was detected on radar near the Eldorado Springs area of Boulder County. 

"This is a privately-owned aircraft; this is not an Air Force plane," said Vinnie Montez with the Boulder County Sheriff's Office.  

The aircraft is believed to be a single-engine plane, but the specific make and model remain unconfirmed. Investigators said the tail number is being withheld pending notification of the potential victims' families. 

Investigators didn't confirm the number of passengers on board the plane. 

The search area is south of the City of Boulder and to the west of Highway 93 all the way to the Continental Divide.

"We're going to ask the public to not fly any drones in the area," said Montez as to not interfere with search operations. "If anybody happens to be hiking today, hiking in the backcountry, the southern part of Boulder County and in the mountain areas, and do come across what looks like the remnants of a flight crash, please let us know by dialing 911." 

Boulder County authorities said they did find some wreckage south of the Flatirons but haven't confirmed whether it is related to the missing plane. 

First responder crews, fire districts, search and rescue, and Boulder County Open Space crews were dispatched on Sunday night. They have been searching on foot and also using drones. Ground searches were paused overnight due to the rugged terrain. Those searches resumed Monday morning once there was enough daylight.