A321
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Human-Machine Interface; Situational Awareness
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance
Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure
We were flying the IVANE RNAV STAR routing. We had checked to be certain that the arrival was set up and briefed the way it was charted. At some point we were cleared to cross MAYOS at FL220. The fact that it was a hard altitude as opposed to the window of FL260 to FL220 didn't dawn on me until we were too high to make the crossing restriction. We advised ATC we not be able to make the restriction. The First Officer was the Flying Pilot and I was the Monitoring Pilot.I think this was a case of thinking you heard what you expected to hear and not what was really said. We expected to cross MAYOS as per the OPD [Optimized Profile Descent] and the lower; hard altitude was not what was loaded.If we are going to be expected to fly these types of arrivals; then let us fly them as published. If ATC keeps modifying these things mistakes of this kind will probably continue. We've been given a lot of guidance on these arrivals. But what I was not prepared for (but will be in the future) was for a significant modification that involved not being cleared to descend via; but instead simple step down altitudes that completely negate what was set up in the FMS. We don't need these complicated arrivals in 2013 if our clearances only mimic the arrivals of 20 years ago. Clear us and let us do it and get out of our way or give us less complicated arrivals. If ATC can't or won't do it; then I fail to see the value of OPD's.
When cleared to cross MAYOS at FL220 (vice the charted 'between FL260 & FL220') on the IVANE RNAV STAR to CLT; the Pilot Not Flying of an A321 failed to program the change in the FMS and; as a result; was unable to comply with the more restrictive clearance.  The reporter took umbrage with the frequency with which ATC modifies OPD (Optimized Profile Descent) STARs rather than clearing flights to descend 'via' them.