Skylane 182/RG Turbo Skylane/RG
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 8; Flight Crew Type 118
Distraction; Situational Awareness; Workload
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Procedure; Aircraft; Weather
Inadvertent controlled flight towards terrain. During vectors to the final approach course; this light GA aircraft (C182) was experiencing moderate to heavy turbulence and the pilot was working very hard to keep the aircraft on course and on altitude. The turbulence continued past the Final Approach Fix and upon breaking out of the clouds at 1000 ft MSL; the PIC noticed that he was below the visual glideslope indications from the field but was still showing on glideslope on the aircraft navigation system. It was at this point that the pilot recognized that the vertical glideslope indicator inop flag was now displayed; but the PIC had not noticed a flag previously on the approach. It is likely that the vertical glideslope had stopped functioning at some point during the approach and the pilot's scan had broken down due to the additional difficulty posed by the challenging wind conditions and had thus allowed the pilot to unknowingly descend below glideslope. Fortunately the cloud cover was high enough that visual cues allowed the pilot to recognize and correct for the deviation once below the clouds. No low altitude alert was given by the Tower during the approach.
C182 pilot reported descending below glideslope on an RNAV approach and noted that the glideslope indicator was inoperative only after seeing the visual glideslope indicators showing that the aircraft was below the glideslope.