Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Situational Awareness; Time Pressure
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Company Policy; Human Factors; Weather
It was my second day on the line. This was a repositioning  flight with two other crew members in the back who I was taking to ZZZ to fly their lines. I was on standby for the first half of the day and I had just flown ZZZ to ZZZ1 then to ZZZ2 and was in IMC from take off to landing on each flight. I was unaware upon leaving ZZZ1 that they had scheduled me to fly these other pilots to ZZZ after reaching ZZZ2. So I operated the flight and all went according to plan except I had an unstable approach into ZZZ. Using the auto pilot for the approach I ended up descending below minimum altitude for the final approach fix and continued well below glide slope until I was approximately 1200 AGL at which point I disconnected autopilot; increased power to help arrest the descent rate; caught up to the glide slope and hand flew the rest of the approach. I relied too heavily on the autopilot and lost situational awareness. I also could have asked one of the other pilots to act as copilot.I think it would be safer to not have new hire Captains fly without an FO (First Officer) in hard IMC for multiple legs even if it is just a reposition flight. And if there is a crew member on board they should sit right seat.
Pilot reported inadvertently descending below minimum approach altitudes in instrument conditions and cited automation dependency as a contributing factor.