Small Transport
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 200; Flight Crew Total 3900; Flight Crew Type 200
Human-Machine Interface; Situational Awareness
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Airspace Structure; Human Factors
Approach Controller gave me a tight 90 degree intercept to final approach course. After realizing he flew us through the course he turned me 135 degrees right toward the airport to reintercept course. While doing so; I failed to set the altitude hold on the autopilot and descended 300-400 feet below the MSA. Upon notification from ATC about low altitude I made the adjustment back to the proper altitude. Contributing factors: night/IFR/improper intercept/failure to hit altitude button.
Socata TBM pilot reported descending below the Minimum Safe Altitude (MSA) following a failed intercept to the final approach course.