Narrative:

While descending via the hyper 4 arrival the FMS went into sequence inhibit mode (uncommanded) after mowat level at 5;000 ft. This caused confusion between the FMS map and our situational awareness which told us to descend down to 4;000 ft for the husel restriction and the FMS which was telling us to stay at 5;000 ft. I had started to descend after mowat but as a result of the confusion quickly leveled off due to the FMS indicating 5;000 ft at the next fix. After a few seconds I determined the error with the FMS and had to do a rapid descent to make the husel restriction; however this restriction was complied with. I am still unsure why the FMS went into sequence inhibit. Additionally and unrelated to the first automation error; during the visual approach into runway 1R the autopilot had difficulty capturing the localizer due to a strong tailwind on base. This resulted in a significant deviation (half scale) towards the parallel runway before the deviation was corrected. The FMS error may have been caused by an error a few minutes prior where when attempting to sync the heading bug the heading mode on the fcp was hit instead; however this error was immediately noticed and corrected with no deviation from the desired flight path. This was the only abnormal event that occurred before the FMS error; but doesn't seem to explain what happened. The localizer capture error was caused by a strong crosswind on the final approach course. This type of error seems to occur on a regular basis if the autopilot is allowed to capture on its own.

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Original NASA ASRS Text

Title: CRJ200 First Officer describes some auto flight anomalies that are common and may be attributed to FMS and or autopilot design.

Narrative: While descending via the HYPER 4 arrival the FMS went into sequence inhibit mode (uncommanded) after MOWAT level at 5;000 FT. This caused confusion between the FMS map and our situational awareness which told us to descend down to 4;000 FT for the HUSEL restriction and the FMS which was telling us to stay at 5;000 FT. I had started to descend after MOWAT but as a result of the confusion quickly leveled off due to the FMS indicating 5;000 FT at the next fix. After a few seconds I determined the error with the FMS and had to do a rapid descent to make the HUSEL restriction; however this restriction was complied with. I am still unsure why the FMS went into sequence inhibit. Additionally and unrelated to the first automation error; during the visual approach into Runway 1R the autopilot had difficulty capturing the localizer due to a strong tailwind on base. This resulted in a significant deviation (half scale) towards the parallel runway before the deviation was corrected. The FMS error may have been caused by an error a few minutes prior where when attempting to sync the heading bug the heading mode on the FCP was hit instead; however this error was immediately noticed and corrected with no deviation from the desired flight path. This was the only abnormal event that occurred before the FMS error; but doesn't seem to explain what happened. The localizer capture error was caused by a strong crosswind on the final approach course. This type of error seems to occur on a regular basis if the autopilot is allowed to capture on its own.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.