Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Instrument; Flight Crew Private; Flight Crew Multiengine
Flight Crew Last 90 Days 75; Flight Crew Total 7000; Flight Crew Type 500
Situational Awareness; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Weather; Aircraft
FMS failed on GPS approach. Aircraft descended 400 FT below final approach fix altitude on GPS Runway XXR. Pilot corrected event manually by times disengaging autopilot.
A CE525 FMS failed while the single pilot was on a GPS approach so after descending 400 FT below the final approach fix altitude he disconnected the autopilot.