Embraer Legacy 450/500
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Confusion
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Weather
During descent to CRQ both crew members realized that the aircraft had departed its course and gone in to a MANSEQ [manual sequence] heading approximately 30 degrees off course from direct to the fix ESCON. Both of us were preoccupied with the failure of one of our engine anti-ice systems and working the radar with inclement weather in the area. We aren't quite sure as to exactly what caused the deviation; other than that it probably had something to do with the fact that ESCON was a fix on the ILS approach that we had programmed; as well as a fix on the filed flight plan. We must have linked the ILS fix rather than the flight plan fix at some point therefore caused the logic to think it was time for MANSEQ and vectors for the approach. The deviation was quickly caught and I don't think we were very far from course; however ATC did inquire as to our course. Tough one; since we still aren't sure what the logic did although I think fixating on the satellite weather on the MFD may have had a great deal to do with it. We were scaled down in range to such an extent to look at the weather that we weren't able to notice the flight plan after the fix leading up to ESCON. I realize now; this is one of the pitfalls in over reliance on satellite radar rather than forward looking radar.
Embraer Legacy 450 Captain experiences a track deviation during approach to CRQ; possibly due to misprogramming the FMS. The error went undetected initially due to preoccupation with satellite weather which completely filled the MFD.