A De Soto couple in a home-built helicopter crashed Wednesday in a rural Douglas County creek bed after what officials described as a mechanical failure.

But even after a free-fall of 1,500 feet, both passengers survived, officials at the scene said Wednesday.

The male pilot was flown from the scene of the crash just east of Baldwin City to Kansas University Hospital with nonlife threatening injuries. His wife, who was riding in the RotorWay Exec 162F kit helicopter, was not seriously injured.

The pilot told officials at the scene that the helicopter was flying at about 1,500 feet when he heard a noise and some part of the helicopter malfunctioned.

“He heard a loud knock in the rear of the craft,” Simoneau said at the scene.

The privately owned helicopter crashed soon afterwards.

Both Douglas County Sheriff Ken McGovern and Kansas Highway Patrol trooper Casey Simoneau declined to name the couple until the National Transportation Safety Board completed its investigation of the crash.

Police were sent to the scene along the 300 block of 2200 Road at about 3 p.m. after the passenger called and reported the crash.

When police arrived at 3:19, the found the woman outside waving them down from a field as the helicopter sat upside down in a nearby creek bed.

“It just took a little while to find her, to get her oriented to where she was,” said Lt. Kari Wempe, a Sheriff’s Office spokeswoman.

The helicopter did not catch on fire or have any other serious issues, McGovern said. The pilot’s wife told officials that he had flown such helicopters for more than 20 years.