Witnesses told The Arizona Daily Star the helicopter crashed into a fence in front of the house on Park Avenue just south of Glenn Street.
The helicopter is owned by Colorado-based AirMethods. Craig Yale, vice president of corporate development for AirMethods, said they were aware of the crash and have a management team headed to the site.
Federal Aviation Administration officials said the helicopter was traveling to Douglas from the University Medical Center when it crashed about 1:45 p.m. Wednesday but was not transporting a patient at the time.
The helicopter was in contact with air traffic controllers before the accident, and there was no indication of trouble, FAA spokesman Lynn Lunsford said.
Ricardo Carrasco told the Star he saw the helicopter plummet to the ground after the rotors stopped working. He says the pilot managed to steer it away from the house.
Tucson firefighters extinguished the fire. No injuries were reported on the ground.
A University Medical Center official said the hospital was not yet able to release any information on the two survivors.