Date: 201205
Local time of day: 0601-1200
Location: PHX.Airport, AZ
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZAB
ATC / advisory: TRACON P50
Reporter organization: Air Carrier
Reporter function: Captain
Human factors: Communication Breakdown; Confusion; Time Pressure; Workload; Distraction; Human-Machine Interface
Second reporter function: First Officer
Anomaly: ATC Issue All Types; Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Contributing factors: Procedure; Human Factors; Chart Or Publication; Aircraft
Primary problem: Human Factors

Narrative: We were on the GEELA 6 Arrival; planning on landing 25R. The GEELA Arrival has been printed with different errors in the last two revision cycles; and corrected with NOTAMS and manual changes to the route in the database over the last several months. They finally appear to have gotten it right; though apparently not right enough that they can just let us fly it as published. The current version has eleven altitude restrictions (many of them include two altitudes to be between) and five speed restrictions. We had programmed the arrival into the FMC; and briefed all the waypoints; altitudes; and speeds. We were then cleared for the arrival; but told to maintain 250 knots. More programming. Then ATC vectored us off the arrival. When cleared to descend 'via' the arrival; we set 4000 feet into the Altitude window. Since we were now off the arrival; we didn't want to descend to 4000 feet; so had to wait for a break in the radio traffic and clarify which altitude to descend to. The Controller did not appear to understand the problem but--on the second try--issued us an altitude that we were very rapidly approaching and for which had to abruptly level off. Then he gave us another vector back onto the arrival; and recleared us to descend via the arrival. I asked if he still needed the 250 knots; and he said; 'That will work.' I assured him that it wouldn't; as the next point had a 265 knot restriction; and the one two more down the road was at 230 knots. He then clarified that we should maintain 250 now; and then comply after HYDRR (250 knot restriction; there). In the time [it took to resolve this issue] we had gone through FL180...both of us had set our altimeters; but the continued conversation with ATC distracted us from doing the Descent Checklist until about 13;000 feet.Phoenix has about the most complex arrivals that we fly; but apparently they don't work. I would suggest that they either be simplified to allow ATC more flexibility or not issued as a clearance if they are going to be routinely interrupted. Between the extra workload of programming (and reprogramming) them; briefing (and then re-briefing) them; and coordinating the changes to them with ATC; it is overly distracting in an already busy phase of flight. At the very least; they need to understand the ramifications of their changes.


Second narrative: Multiple speed assignments and incomplete clearances increased our arrival workload to the point that we accomplished our Descent Checklist late and almost forgot to turn the seatbelt sign on prior to landing. While still cruising at FL250; ATC had assigned 280 knots. Later on the arrival; we were told to comply with the speeds on the arrival. We had not yet been cleared to 'Descend 'via' the GEELA 6;' so we asked if we were cleared to descend 'via' the arrival; and then; for the first time; we were in fact cleared to descend 'via' the GEELA 6 Runway 7R transition. This was a blatant case of over control and it creates an environment prone to errors. ABQ Center and PHX Approach are over controlling airplanes on all the arrivals into PHX; and it is frustrating. We are trying to be good citizens and comply with the Controller instructions; but it is clear that they are not seeing this from a flight crew's perspective. The issuance of speeds while VNAVing on an arrival has the potential to cause missed altitude restrictions. Clearances off of the arrival without a new altitude is wrong. Once cleared for the arrival; they need to let us fly it - period.


Synopsis: A B737-700 flight crew reported their concerns about ATC's frequent re-clearances given to aircraft previously cleared to descend 'via' the complex RNAV STARs into PHX.