Airbus Industrie Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
Human Factors; Procedure; Aircraft
Once again the IVANE 1 bit us in the butt. As before ATL Center cleared us to a hard altitude of FL220 at MAYOS. The First Officer was pilot flying and we had briefed this thoroughly with a warning that this clearance required two changes in the MCDU programming...and in fact we found another 'got U' on this terrible [arrival]. We cleared the constraint at MSTRD and changed to a hard constraint FL220 at MAYOS. We called Approach and were cleared to descend via the IVANE 1. The First Officer put 6;000 in the FCU and as we passed MAYOS he engaged vertical guidance. The airplane disregarded the FL220 constraint at the following waypoint and started descending immediately. We stopped it as soon as we saw the amber over the next waypoint; but it was already an altitude deviation. This occurred because of expectations and because ATL is not involved in the descent. When in the descent mode the plane will follow the profile; but when ATL gives you a hard altitude; it is in descent mode; but at MAYOS; because we did not re-enter a cruise altitude in the progress page (note this is a workaround we should not need to do-due to a bad policy and procedure). The plane left FL220 immediately to a 1;000 FT per minute descent. It is impossible and not practical for the crew to think of every variation of procedure we have to remember because we have to work around a bad policy and procedure. We change original procedure because we don't want to pay for software upgrades; so we make protocol; then we find [in order] to make it work we have to redefine secondary failures into primary failures to make our workaround 'work.' Company culture is to change what is Airbus recommended; intuitive and simple to save money. This IVANE 1 arrival is riding the speedbrake; giving a bad ride; and using fuel [in order] to enhance throughput in CLT by what a few operations per hour. As soon as you have to deviate for weather or other reason or get another speed restriction by ATC; you set us up for failure.
Airbus Captain reports descending early on the IVANE 1 arrival to CLT due to ATC changes to the arrival and FMGC design issues.