BAe 125 Series 800
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Multiengine
Flight Crew Last 90 Days 30; Flight Crew Total 6700; Flight Crew Type 1300
Other / Unknown; Workload; Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Overcame Equipment Problem; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Aircraft; Human Factors
Hawker 800 was on vectors heading 280; and had been given a climb to 14;000. Aircraft was light and was climbing fast. Departure Controller issued a clearance direct to Solberg (SBJ) VOR to pick up our route (V3) back down to Baltimore. The direct clearance; and level off occurred nearly simultaneously. Undetected by both pilots; the left Automatic Flight Control System (AFCS) had failed. The failure had occurred while the aircraft was in heading mode and vertical speed mode; so the aircraft continued on its heading and at its last climb vertical speed. Neither pilot remembers hearing an autopilot disconnect warning. Pilot flying was investigating why the aircraft was not responding to the turn towards Solberg. At 14;200 FT pilot not flying realized aircraft was climbing through its assigned altitude and that the autopilot had failed. Pilot not flying called the discrepancy. Pilot flying halted the climb at 14;350 FT and began slow descent back to 14;000; and initiated a turn to SBJ. ATC Controller called to confirm the aircraft was stopping climb at 14;000 FT. There were no other aircraft in the vicinity of the incident (At least nothing on TCAS). Pilot flying continued flight with no further incident. Contributing factors; both pilots have been flying only once a week; and on short duration flights. Scans have slowed. Momentary task saturation as turn; level off and autopilot failure occurred (or at least was discovered) at the same time. Hard failure of left AFCS.
Hawker 800 Captain experiences an autopilot failure; without warning; at precisely the time the aircraft needed to level off and turn to a fix. An overshoot occurs which is quickly corrected. Infrequent flying on short trips was cited as a factor in the incident.