Date: 201701
Local time of day: 1201-1800
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Light: Daylight
Aircraft: SF 340B
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Aircraft component: Electrical Distribution Busbar
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On descent approximately 20 nm from the airport we received a warning annunciator that we lost the left main bus; the left essential bus; and the inverter. The autopilot simultaneously kicked off; and the Captain's side Electronic Flight Instrument System (EFIS) and Electronic Attitude Director Indicator (EADI) screens were blank. Additionally; all the captain's side instruments were frozen. The left side engine instruments were not working; but the left engine appeared to still be running normally. I then gave control of the aircraft to my first officer because his instruments were still working. We requested to circle [the] airport so we could work the problem. While [the First Officer (FO)] flew; I ran the essential bus and main bus QRH. I switched to the number 2 inverter and it was working. [The FO] and I also checked our circuit breakers and saw none popped. I then ran the EFIS Failure QRH. This did not get either of my EFIS or EADI screens working. I next contacted our flight attendant and notified her of the situation. [The FO] and I completed a descent and approach checklist. We next attempted to lower the landing gear in preparation for landing. The nose gear indicated down and locked; but both the main gear did not. I executed the Gear Down Unsafe Condition QRH. This directed us to the Hydraulic QRH; and the hydraulic caution light had come on when attempting to extend the gear. We had low pressure in the main; emergency; and outboard brake accumulators. There was still pressure in the inboard brake accumulator. The QRH directed us to do an emergency gear extension and HYDR Procedure 1. This resulted in all 3 gear indicating down and locked. However; the flaps remained retracted as commanded by the QRH. Lastly; I executed the landing QRH. Since we were doing a landing with no flaps; suspect gear condition; and possible loss of braking and nose wheel steering; I told [the flight attendant] I would give a brace warning over the PA before touchdown with a possible evacuation on the runway if necessary. We then requested to do a low approach over the runway to have the tower check our gear. The tower indicated that all three gear appeared to be down. Lastly; we continued in the traffic pattern to attempt to land. Before landing I gave a brace warning over the PA. We then touched down normally using reverse thrust to slow down. Slowing through 80 kts; [the FO] transferred the controls to me while continuing to apply wind correction with the yoke. The brakes worked to bring the aircraft safely to a stop on the runway. I had [the FO] shut down the engines with the fire handles. I was concerned about the brakes not working; and using the fire handles would prevent the aircraft from jumping forward as when using the condition levers to shut down. After shutting down; I checked that everyone in the cabin was ok. The airport emergency crew met us at the runway and brought a bus to have the passengers deplane normally on the runway. The incident ended safely; with no injuries or damage.




Synopsis: SF340B Captain reported the loss of the left essential bus and other associated systems. The flight crew executed a successful no flaps landing.