What happened
While on approach to land, the pilot moved the landing gear selector handle to the down position, but the landing gear failed to extend. The flight subsequently departed the airport traffic area, and the pilot attempted to deploy the gear using emergency extension procedures; however, these attempts were unsuccessful.
The pilot performed a low approach past the control tower to confirm the gear status and received advice from the tower that the gear appeared to be down. The flight returned to the airport for landing, but upon touchdown, the landing gear collapsed.
Following the incident, while attempting to move the aircraft from the runway, the pilot was instructed to attempt the emergency gear extension method again. This second attempt failed because the pilot released the clutch while cranking the gear down, whereas the correct procedure required holding the clutch in during the process.
The investigation
An examination of the aircraft revealed a failure of the dynamic brake relay. The function of this relay is to prevent the coasting of the gear motor and gears by momentarily reversing the motor once the up limit is reached. The failure of this component prevented the intended operation. Following the replacement of the failed relay, the landing gear operated normally.