Date: 201709
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Super King Air 200
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Ambulance
Flight phase: Landing
ATC / advisory: Tower ZZZ
Aircraft component: Main Gear
Component problem: Malfunctioning
Reporter organization: Air Taxi
Reporter function: Other / Unknown; Single Pilot
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Confusion; Distraction; Human-Machine Interface
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Equipment / Tooling; Human Factors; Aircraft
Primary problem: Aircraft

Narrative: After completing a normal flight within normal operating procedures; during the visual approach all indications were 'NORMAL': Landing gear 3 GREEN/NO RED; No gear warning horn. Flaps FULL.Upon a normal landing in ZZZ on Runway XX; both mains touched ground but before the nose wheel came down I noticed the aircraft's left side settle more than normal as if a gust pushed it down; I heard the gear horn and proceeded to execute a go around. While executing the go around maneuver I noted that the flaps would not retract when selected and the gear showed an 'unsafe light' in the handle when retracted.I [advised] ATC and asked for holding instructions. I entered a holding pattern within close proximity to the airport to diagnose the situation. The flaps were stuck in the FULL DOWN position and gear horn would not silence. I reviewed the Landing Gear abnormal/emergency procedures then attempted a normal gear extension (electrically with gear handle before attempting a manual extension) which only was able to extend the nose gear. I then completed the checklist for the manual gear extension procedure and was only able to get green lights on the nose and Right main. From the execution of the go around with Flaps stuck in the FULL DOWN position the GEAR WARNING horn was audible and would not silence: which is a normal function of the gear system. I then executed a low approach so ground personnel could inspect and see if the left main was in fact down or still in the wheel well. After the low approach no one was able to see anything due to the darkness from the ground; so I was cleared to land on Runway XX and I did a second low approach and was told by ground personnel that the left gear looked to be down so I made a visual pattern to land back on Runway XX. I communicated with the medics on board regarding the potential gear issue and briefed them on emergency landing procedures. As soon as I touched down the left main landing gear collapsed. On landing rollout I maintained center line as best as I could and shut both engines down and gang barred the master/electrical switches. We performed an uneventful egress through the aft air stair door.




Synopsis: BE200 pilot reported landing after unsuccessful attempts to fully extend the gear resulting in left landing gear collapse on landing.