A C525 crew reported a track deviation during approach after a destination change to a nearby airport with the same final approach heading. A FMS design issue failed to reprogram the new approach inside the final approach fix.
Synopsis
A C525 crew reported a track deviation during approach after a destination change to a nearby airport with the same final approach heading. A FMS design issue failed to reprogram the new approach inside the final approach fix.
Narrative
While being handed off from Approach to Tower; passenger advised crew that he wanted to go to a nearby airport instead of the filed airport. Crew advised approach of airport change; approach told crew to request change with Tower. Tower instructed crew to maintain 8;000 FT overfly the runway and expect a right turn and was told to contact Approach; that the crew complied with. Approach vector aircraft to new destination for the visual approach to Runway 35R. The crew loaded the ILS 35R approach into the Collins FMS to back up the visual approach to Runway 35R. The inbound heading was 280 that was inside of the final approach fix; 2 miles before the FAF crew advised Approach that the airport was insight. Crew was given a clear for a visual approach to Runway 35R and to contact Tower who gave a clear to land. Crew armed the approach mode to intercept the final course and the autopilot began a turn to final 1 mile inside of the final course; because the auto-tune will not turn properly if the vector is inside of the final approach fix. After the aircraft rolled wings level; the crew disengaged the autopilot; made a turn back to the final; head 260 and made a sloe in tight approach to Runway 35R and landed without incident. The Collins FMS-3000 flight management box needs a vector of 2 miles outside of the final auto-tune and to properly activate. It was still locked onto the original destination's 35R ILS. The morning light and rough ride with a 2;000 FT thin scatter layer also contributed to this incident.
Second reporter narrative
Tower issued exit runway a high speed. Quickly exited and stopped short of taxiway but had wing on blind side to the right slightly overhang intersecting taxiway when stopped to contact ground.No conflicting ground traffic on taxiway. To have avoided the erroneous turn to localizer; will not fly auto pilot in that situation. The runways at both airports were 35R. On landing a discrepancy was listed on MEL. The manufacture is checking equip now. Have discussed issue with Collins Rockwell as to why this occurred and have an understanding on how to discover and avoid this FMS sequencing issue. As to intersecting taxiway overhang; could have declined the high speed to allow more time to slow further before exit and be mindful of the fact the angle of intersection of high speed and the intersecting taxiway requires an earlier stop to avoid wing intrusion.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.