A321
Communication Breakdown; Human-Machine Interface; Confusion
ATC Issue All Types; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory
Human Factors; Chart Or Publication; Procedure
We passed BLH on the GEELA 6 RNAV STAR into KPHX. I don't remember specifically but it was a good distance prior to SCOLE intersection we were told to descend to FL240 and slow to 250 KTS. (SCOLE has a restriction of FL250 and 280 KTS on the RNAV.) After we had passed SCOLE we were issued a clearance to descend via the GEELA 6 RNAV arrival Runway 7L transition and comply with speed restrictions. Shortly after we passed the next intersection SPINK; ZLA Center asked us for our speed and we told him 250 KTS. The Controller said we needed to comply with speeds on the arrival. So we increased the speed to 280 KTS and continued with the RNAV arrival. The Controller was very busy with lots of arrivals and spacing seemed to be an issue. The Controller had to slow us and descend us prior to SCOLE to make proper spacing. His clearance to descend via and comply with speed restrictions did not come until after we had passed SCOLE. The next intersection which is SPINK; only has a crossing restriction and no speed restriction. The next speed restriction on the arrival does not occur until HYDRR at 265 KTS. I was holding the last assigned speed while I complied with the crossing restrictions. Another possible cause is that I may have a misunderstanding of the requirements after a change has been issued by a Controller. It would have been less ambiguous for the Controller to issue the speed he expected us to be at when he issue the descend via and comply with speed; since we were already assigned a speed below the first intersections arrival speed and already past that intersection. These new arrivals are designed to reduce problems and facilitate the flow of traffic efficiently. When controllers change the speeds and altitudes on a descent via that has comply with speed restrictions; we seem to have problems. I am in contact with the training department to see what I need to do to make sure this does not happen again.
After previously being cleared to descend to FL240; maintain 250 KTS; the flight crew of an A321 was later cleared to descend via the GEELA RNAV STAR into PHX; comply with speed restrictions.  Because they were maintaining the lower assigned speed at the time of passing waypoint SCOLE--which has a charted crossing restriction of 280 KTS--they continued to maintain the prior restriction.  This was not ATC's intent and they were asked to accelerate to 280 KTS and to comply with subsequent published restrictions on the STAR.