Bonanza 33
Flight Crew Instrument
Flight Crew Last 90 Days 15; Flight Crew Total 660; Flight Crew Type 28
Human-Machine Interface
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Human Factors; Aircraft
Preflight; engine start; run-up; takeoff; climbout and transition to cruise were all normal and uneventful. Overhead [an airport] uncoupled autopilot and throttled back for descent into ZZZ1; but discovered that throttle had no tension and no response to any inputs (engine was currently at 2300 rpm and 23 inches MP).Turned aircraft around toward home base ZZZ; and called flying club operations manager on cell phone. Discussed situation; determined that deploying speed brakes; lowering landing gear and 10 degrees flaps reduced speed from 165 kts to 125 kts. Discussed landing at ZZZ2 or ZZZ3 because of longer runways; but pilot determined that the aircraft could be landed safely at [home base.]Contacted ZZZ tower; ATC held all surrounding traffic; notified fire and rescue personnel; and directed pilot to left downwind for rwy 27L. Pilot extended downwind for a longer final; base and short final were on glideslope; pulled mixture to idle about 100 yds from threshold. Aircraft landed safely and had enough momentum to turn onto taxiway Delta and clear the active runway.After aircraft was towed to ZZZ maintenance hangar; inspection showed that the throttle cable had become totally unattached to throttle valve. Aircraft is to be repaired; proper performance checks done; and placed back into service in flying club.
When the Beech F33 pilot found the engine unresponsive to throttle inputs he declared an emergency and returned to his departure airport utilizing drag devices to slow the aircraft until short final and then shut down the engine via the mixture control. Following a safe landing maintenance discovered the throttle actuating cable completely unattached at the throttle end.