What happened
Following a successful patient transfer between two regional airports, the flight crew began a night flight to return to their home base. While initially cleared for an RNAV (GPS) runway 17 instrument approach, the crew discussed canceling the approach to perform a circling maneuver to land on runway 27R. The approach procedures for the area specifically prohibited circling to runways 27R or 35 during nighttime operations. After establishing visual contact with the runway, the pilot requested to switch to VFR flight rules and requested landing on runway 27.
Air traffic control cleared the aircraft to overfly the field and enter left traffic for runway 27R. During the maneuver, the crew requested increased intensity for the runway lights, but were informed the lights were already at maximum brightness. As the aircraft transitioned to the downwind leg, the pilot flying expressed difficulty locating the runway. During the subsequent maneuvering, the crew noted a nearby mountain and experienced a period of high-stress communication regarding airspeed and terrain avoidance. The aircraft eventually impacted the terrain during this phase of flight.
Findings
Data from ADS-B tracking revealed that the aircraft was operating significantly below established safety minimums. At the moment the crew reported seeing the runway, the aircraft was approximately 360 ft below the instrument approach minimum descent altitude (MDA). By the time the aircraft crossed the published missed approach point, it was 6ered 660 ft below the MDA. The flight path showed the aircraft overflew the destination at 775 ft msl and descended to 700 ft msl while on the downwind leg. The terrain impact occurred while the aircraft was at an altitude of approximately 875 ft msl.