Incident
The pilot reported that at 1300, after completing a photo mission, they were returning home. When the flight was within 10 miles of the airport, the pilot initiated a letdown from 8000 feet. To facilitate the descent, the pilot elected to lower the landing gear. When the gear handle was placed in the down position, there was no response. Several additional attempts to lower the landing gear also failed.
Once the pilot realized that the efforts to lower the landing gear were unsuccessful, they elected to execute a gear-up landing. The airplane touched down and stopped on the runway. Emergency equipment was available for the landing.
Examination
Examination of the airplane disclosed that the landing gear motor solenoid control wire had an intermittent terminal connection under the rubber insulation boot on the solenoid. According to the maintenance manual, this condition would not allow the solenoid to close and run the landing gear motor.