A320
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Other / Unknown
General None Reported / Taken
Human Factors; Procedure
Assigned IVANE4 Arrival South Transition. Several speed changes and heading changes after level-off were issued including a temporary Cleared Direct to MAJIC. After the MAJIC clearance; we were assigned a SW heading and speed reduction to 250 knots. Then clearance to 13;000 FT was issued. Shortly thereafter; we were assigned '300 knots or greater'; cleared 'direct to HIKRR; cleared IVANE4 arrival-South Transition; resume published speeds at HIKRR.' We were anticipating landing on runway 23 therefore the bottom end of the constraint windows are preferred in order to remain on profile. At this point we initiated a slow descent to cross HIKRR at 11;000 FT in order to maintain the 23 arrival profile. Passing 11;600 FT Atlanta Center gave us a frequency change to approach control on 126.15 and stated that we were supposed to be at 13;000 FT. We responded [that we] were cleared direct HIKRR not MAJIC and that our chart indicated HIKRR at or above 11;000 FT. He then told us to switch to Charlotte approach on 126.15. We then contacted approach and asked them if they had an issue with our altitude. They said they did not. Initially; I thought the Atlanta Center controller assumed we were going direct to MAJIC which restricts descent to 13;000 FT. After running the situation through my mind after landing; I wondered if the controller expected us to maintain 13;000 FT until we were actually on the arrival (we were approaching HIKRR from the ENE) which would have put us high on a South Transition to RW23. In retrospect; we could have maintained 13;000 FT until reaching HIKRR and then conducted a more aggressive descent for the 23 approach. The fact that I am even writing this indicates the clearance instructions were vague. I believe a clearance stating 'cleared direct HIKRR; maintain 13;000 FT until HIKRR; at HIKRR cleared IVANE4 arrival South Transition; resume published speeds at HIKRR' would have alleviated any question concerning the arrival.
An A320 flight crew on vectors enroute to CLT was cleared to '...maintain 13;000 FT; maintain 300K or greater cleared direct to HIKRR; cleared the IVANE arrival; south transition; resume published speeds at HIKRR.' Then; in preparation for their planned landing on Runway 23; they initiated a slow descent to cross HIKRR 'At or above 11;000 FT' charted restriction.  When given a frequency change to Approach Center remonstrated them for failing to maintain 13;000 FT.