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Incidents related to Issue 1 incident related to this issue.

Issue: interface may be poorly designed (Issue #39)
Description: The pilot-automation interface may be poorly designed with respect to human factors considerations, possibly resulting in poor pilot performance or pilot dissatisfaction.

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  2. Accession Number: 54353
    Synopsis: ACR MLG OVERSHOT CLRNC ALT DURING DESCENT TO FL210. F/O PF SELECTED WRONG PMS MODE CANCELLING AUTO CAPTURE.
    Narrative: FROM CHS TO CLT I WAS FLYING THE ACFT VIA AUTOPILOT INPUTS THROUGH THE FMA. PMS WAS NOT ENGAGED. AT APPROX 100 MILES FROM CLT, I ASKED THE CAPT TO REQUEST DESCENT CLRNC FROM ATC. ATC ADVISED US THAT HE WAS UNABLE TO DESCEND US DUE TO TRAFFIC AND TO STANDBY FOR LOWER. AT APPROX 60 MILES FROM CLT, WE WERE GIVEN A DESCENT CLRNC. I INITIATED THE DESCENT AND THE CAPT PROCEEDED TO GET THE ATIS INFO AND COMPANY CHANGEOVER INFO. SHORTLY THEREAFTER, WE WERE GIVEN ANOTHER DESCENT CLRNC TO FL210, FOLLOWED QUICKLY BY A HEADING CHANGE AND A REQUEST TO SLOW TO 250 KNOTS, AND EXPEDITE OUR DESCENT. I ACKNOWLEDGED THE TRANSMISSIONS TO ATC. THE REQUEST TO SLOW TO 250 KNOTS CAME AS WE WERE APPROACHING FL210, HOWEVER, I DID NOT NOTICE THAT WE WERE THIS CLOSE TO LEVEL OFF DUE TO MY PREOCCUPATION WITH FLYING THE ACFT, COMMUNICATING WITH ATC, AND TRYING TO CONFIGURE THE ACFT FOR AS RAPID A DESCENT AS POSSIBLE WHILE SLOWING SIMULTANEOUSLY TO 250 KTS. DUE TO THIS ERROR ON MY PART, I SELECTED IAS HOLD ON THE FLT GUIDANCE CONTROL PANEL. MY ACTION OF SELECTING IAS HOLD JUST AS FL210 WAS BEING CAPTURED DISARMED THE ALT HOLD FUNCTION. AT 20700', THE ALT WARNING SOUNDED. I DISCONNECTED THE A/P AND BEGAN A CLIMB BACK UP TO OUR ASSIGNED ALT OF 21000'. HOWEVER, THE DESCENT WAS NOT ARRESTED UNTIL THE ACFT REACHED 20300'. HAD I OBSERVED ON THE FMA DISPLAY THAT ALT CAPTURE HAD TAKEN PLACE, I WOULD NEVER HAVE SELECTED "IAS". SEVERAL THINGS CONTRIBUTED TO THE DEVIATION: THE CAPT WAS PREOCCUPIED WITH GETTING THE ARRIVAL ATIS, COMPANY CHANGEOVER, AND FAILED TO MAKE THE CALLOUT OF 1000' ABOVE ASSIGNED ALT. NUMEROUS CLRNCS BEING ISSUED BY ATC, REQUIRING SIMULTANEOUS CHANGES IN DESCENT RATE, HEADING, AND AIRSPEED. OVER-RELIANCE ON AUTOMATIC FEATURES OF FLT GUIDANCE SYSTEM WHICH CREATED A FALSE SENSE OF SECURITY. THE FLT GUIDANCE SYSTEM CONTROLS ON THE MLG ARE LOCATED BELOW THE CENTER GLARESHIELD, WHILE THE FMA ARE LOCATED ABOVE EACH PLT'S FLT INSTRUMENT GROUP. WHEN I PUSHED THE "IAS" BUTTON ON THE FLT GUIDANCE PANEL, THE FMA WOULD SHOW THE GREEN "ALT HOLD" ANNUNCIATION REPLACED WITH "IAS", THUS INDICATING THAT THE ALT HOLD FUNCTION IS NO LONGER ENGAGED. HOWEVER, BECAUSE THE FMA DISPLAY WAS OUT OF MY FIELD OF VISION WHEN I SELECTED "IAS", THIS WENT UNNOTICED. SUPPLEMENTAL INFO FROM ACN 53983: FOR REASONS UNKNOWN, IT DID NOT CAPTURE FL210.
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