It happened at about 7:30 a.m. just south of I-8 and Peart Road near Casa Grande Mountain Park.
The chopper rolled as it touched down in the desert.
Aerial video from the Fort McDowell Casino News Chopper showed the chopper in pieces, the cabin of the Hughes 500 on its side, rotors crumpled. The tail tore off the body of the helicopter, landing several feet away.
According to PCSO spokeswoman Tamra Ingersoll, there were three people on board -- the pilot, a technical operator and a mechanic. All three of them walked away from the crash, but were taken to a local hospital as a precaution. That is standard procedure in this kind of situation.
Ingersoll said an apparent engine problem followed by a power failure forced the pilot to make an emergency landing.
The chopper was on a routine maintenance test flight when the pilot put it down.
The helicopter is one of two in the PCSO Air Support Unit. The unit also has a Piper Super Cub fixed-wing plane.
According to the PCSO website, the agency bought the 1990 MD Helicopter 500E, the second aircraft in the unit, in December 2011 with funding from the State Legislature "because available air support was lacking in the county."