Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Confusion; Other / Unknown
ATC Issue All Types
Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Aircraft; Procedure
While approaching DEN; we were on the WAHUU arrival. We were somewhere prior to SAYGE waypoint; when I received a confusing clearance from ATC; 'Callsign; descend via the WAHUU arrival except maintain 1-1-thousand.' As there are some intervening step-down altitudes published; I was unsure exactly what ATC wanted us to do; and so I asked for clarification. The response from ATC was exactly what had been previously said; verbatim. So; I asked; 'am I cleared down to 1-1-thousand at this time?' Then another voice (I assume a Supervisor) came on the frequency and clarified that they wanted us to meet any intervening step-downs; but once reaching 11;000 feet; to maintain that altitude. I feel that the new RNAV arrivals and departures in DEN and other stations are overly complex and require a very high workload at a phase of flight in which there are many other tasks we need to accomplish. There are too many fixes; they are too close together; and the descent rate needed when told to 'descend via...' is highly variable from one fix to another. These arrivals require significantly more attention and 'heads-down' time in the cockpit than traditional arrivals. In addition; the new use of 'descend via' and 'climb via' phraseologies seem to be a work in progress; with constantly varying language used. In another example; just the other day I had some confusion with a 'climb via' clearance: Our Pre-Departure Clearance (PDC) said; 'climb via the SID; except maintain 10;000.' Well; as there are no intervening leveloffs prior to reaching 10;000 feet; this verbiage is totally superfluous. My flight path would be no different if that phrase wasn't in there. Then; after leveling at 10;000 feet; I was given the following clearance; 'Call sign; climb via the SID.' There was no altitude assigned other than the original 10;000 feet. So I have to ASSUME that I am to climb to the top altitude printed on the chart - but I will always ask for clarification if this is not spoken. First of all; I feel the need for such a quantity and such complexity of these RNAV arrivals and departures needs to be re-evaluated and decreased. But barring that result I feel these types of clearances need to be clarified and the language standardized and published. In the descent example; it would have been totally clear if ATC had said; 'Descend via the arrival; but upon reaching 11;000 feet; maintain 11;000 feet.' Similarly; the climb clearance is perfectly clear if the altitude is included in the clearance; i.e.; 'Call sign; climb via the SID to maintain Flight Level 230.'
CRJ200 Captain laments the increasingly complex RNAV arrivals and departures with their associated descend via or climb via clearances with altitude modifications.