Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
On descent into ZZZ; I selected the gear down. The right main gear light illuminated however my nose and left main gear lights remained extinguished; the nose unlocked light was on and the HYD PRESS light was on. I recycled the gear and when I selected 'up' there was no sound or movement to indicate the gear had gone up and none of the lights changed or extinguished. I put the gear back down and the HYD PRESS light extinguished and both HYD FLOW L/R illuminated. I chose to break off to the left and returned to approach frequency so I could resume flight following while running the checklist. I engaged the autopilot while I ran through the checklist. I decided to disengage the autopilot while I dropped the gear however the autopilot did not disengage. I turned the autopilot off with the switch but it remained engaged. I then tried to pull the circuit breaker however neither myself nor my passenger in the copilot seat could pull it. I turned the autopilot switch back on; reengaged the autopilot; and then disengaged it for the second time which finally released the flight controls. I decided to return to ZZZ1; advised ATC; and finished my gear checklist. I did have to blow the gear down and requested emergency vehicles. On the ground; Maintenance inspected the aircraft and there was hydraulic fluid all over the ground and the hydraulic reservoir was completely empty. The aircraft parked with no further incident.
C402C Captain reported a loss of hydraulic fluid caused the landing gear to not extend and autopilot to not disengage; causing an air turn back.