King Air C90 E90
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 120; Flight Crew Total 7415; Flight Crew Type 1000
Human-Machine Interface; Situational Awareness; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance
Aircraft; Human Factors
After leveling off at my assigned cruise altitude of 10;000 MSL using the autopilot altitude preselect; the Controller asked me to say altitude.  When I looked at my PFD altitude display (Garmin 600) it showed approximately 10;600 FT.  When I checked the mechanical back up altimeter it showed 10;000 FT.  When I cross checked the two altimeter settings I realized that the back up altimeter setting was not correct.  I disengaged the autopilot and descended to 10;000 FT using the PFD altimeter and reset the autopilot to altitude hold.  After talking with the owner of the aircraft on my return he informed me that the autopilot altitude capture was linked to the mechanical standby altimeter; not the PFD altimeter.  The aircraft was an 'other owner' aircraft that I was flying on an infrequent basis and believed that the altitude management process was controlled by the primary PFD altimeter.  I am now aware that the PFD back up altimeter must be reset at all times along with the primary and secondary altimeters and altitude capture indications must be verified on both altimeters.
A King Air pilot; unfamiliar with the avionics in the aircraft involved; leveled 600 FT above his cleared altitude because the altitude select/capture mode was predicated on the reading from the standby altimeter; not his PFD altimeter; which he had failed to reset prior to takeoff.