Regional Jet CL65; Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Human Factors
I was the First Officer and Pilot Flying for the visual approach to Runway 20 at BMI. We were cleared for the visual and I descended with the glideslope as a backup. Several miles out on the approach; the aircraft looked low and I immediately clicked off the autopilot and corrected the airplane's approach path. As I corrected the aircraft's flightpath; ATC called and said they had received an altitude low warning on our aircraft. We acknowledged and continued the approach and landed safely. The Captain informed ATC that the glideslope was giving incorrect information and ATC informed us that the glideslope was out of service. At this point we realized that the NOTAM for an inactive glideslope was still active and we had briefed that the NOTAM would not affect our approach. This event was caused by a misinterpretation of NOTAMs on the release. This event could have been avoided by thoroughly briefing the NOTAMs as a crew and not relying on a system that was out of service.
CRJ First Officer reported receiving a low altitude alert from ATC on approach to BMI. They realized they were following a glide slope that was NOTAMed out of service.