The single-engine Beech 35 went down near Rakow and Virginia roads in Lake in the Hills about 3:15 p.m. Thursday, according to the Federal Aviation Administration.
The McHenry County coroner's office identified the men as H. Scott Clark, 65, of Lake Forest and Paul San Filippo, 82, of Grayslake. Both men were in the front of the plane but it's not clear who was the pilot, authorities said.
The crash happened east of the Lake in the Hills Airport, in a marshy area near runways at the southwest corner of the intersection, police said.
The "aircraft, a single engine private plane, was airborne in the area immediately east of the Lake in the Hills Airport where it had landed earlier in the day ... witness statements indicate the plane may have been attempting to return to the airport when it began to decelerate just prior to impact," Crystal Lake Police said in a news release.
The Lake in the Hills dispatch center received a 911 call at approximately 3:15 p.m. from a passerby stating that a single-engine private aircraft appeared to have crashed into a pit on the southwest side of Virginia of Rakow roads, said Crystal Lake Deputy Police Chief Eugene Lowery. The crash site is on the border between Crystal Lake and Lake in the Hills.
A witness told authorities the plane was traveling north and appeared to be banking left to line up for a landing at the airport, Lowery said. As the plane banked left to head west, the engine began to decelerate, Lowery said.
There was a strong prevailing wind at the time of the crash, which would have cut into the aircraft as it was making the turn, Lowery said. The witness lost sight of the plane and then heard a loud noise.
Witnesses said they heard the plane and then a loud thud.
Emergency crews had to travel on foot to access the crash site in a marshy area, making it inaccessible to normal rescue vehicles, according to police. Fire crews extinguished a fire caused by the crash and authorities were examining debris, officials said.
The FAA and National Transportation Safety Board are investigating.
Aviation officials were en route to investigate and McHenry County coroner's officials were on the scene.
Tribune reporter Liam Ford contributed