Narrative:

The A320 came over from ZLA on the GEELA4 arrival at FL250. I had a BE90 in front of the A320 that wasn't going to allow me to give a complete descend via clearance for the A320; phx was on the 25L transition. We still; even when not descending via; have to issue the runway transition. Therefore; I gave the A320 the route clearance for the transition when they came over so that I wouldn't forget to issue it. I said 'the A320; after geela cleared the runway 25L transition; cross scole at FL250.' I was going to have to give geela at 150/250k. We are having discussions in my area about the runway transition clearance in isolation and reiterating the altitude assigned at the time in the same transition. We are doing this because we believe it might be; at tacitly; a .65 requirement and it should help reiterate the fact that the pilot is cleared for the transition only and not to descend via. We have had a lot of instances where the pilots construe this clearance as a descend via clearance. In this case; I told them to cross scole at FL250; which is the previous clearance ZLA gave; rather than say 'maintain FL250' and have the pilot possibly cross scole high because of the difference in verbiage. The pilot read back my clearance as follows 'the A320; cross scole at 250; after geela cleared for the 25L transition.' soon after crossing the border; the A320 started down on their own. I asked the A320 if they were descending; they responded 'affirmative; we are descending via the GEELA4 transition; GEELA4.' I told them the transition clearance was a route clearance only; and then amended their presumed clearance to geela at 150/250. Recommendation; first; I think someone needs to discuss with the companies indicating that unless you get an actual descend via clearance; the transition clearance is not a VNAV clearance; only LNAV. We are having a lot of problems with the aircraft assuming the transition clearance is the descent clearance. Second; I think the RNAV arrival work group needs to be convened to discuss this and other issues involving these procedural problems. Also; we are having some difficulty and the pilots as well; with phraseology; since these sorts of clearances are brand new in the NAS.

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Original NASA ASRS Text

Title: ZAB Controller provided a detailed discussion regarding the new RNAV arrival procedures into PHX and the confusing 'descend via' phraseolgy.

Narrative: The A320 came over from ZLA on the GEELA4 arrival at FL250. I had a BE90 in front of the A320 that wasn't going to allow me to give a complete descend via clearance for the A320; PHX was on the 25L transition. We still; even when not descending via; have to issue the runway transition. Therefore; I gave the A320 the route clearance for the transition when they came over so that I wouldn't forget to issue it. I said 'the A320; after GEELA cleared the Runway 25L transition; cross SCOLE at FL250.' I was going to have to give GEELA at 150/250k. We are having discussions in my area about the runway transition clearance in isolation and reiterating the altitude assigned at the time in the same transition. We are doing this because we believe it might be; at tacitly; a .65 requirement and it should help reiterate the fact that the pilot is cleared for the transition only and not to descend via. We have had a lot of instances where the pilots construe this clearance as a descend via clearance. In this case; I told them to cross SCOLE at FL250; which is the previous clearance ZLA gave; rather than say 'maintain FL250' and have the pilot possibly cross SCOLE high because of the difference in verbiage. The pilot read back my clearance as follows 'the A320; cross SCOLE at 250; after GEELA cleared for the 25L transition.' Soon after crossing the border; the A320 started down on their own. I asked the A320 if they were descending; they responded 'affirmative; we are descending via the GEELA4 transition; GEELA4.' I told them the transition clearance was a route clearance only; and then amended their presumed clearance to GEELA at 150/250. Recommendation; First; I think someone needs to discuss with the companies indicating that unless you get an actual descend via clearance; the transition clearance is not a VNAV clearance; only LNAV. We are having a lot of problems with the aircraft assuming the transition clearance is the descent clearance. Second; I think the RNAV Arrival work group needs to be convened to discuss this and other issues involving these procedural problems. Also; we are having some difficulty and the pilots as well; with phraseology; since these sorts of clearances are brand new in the NAS.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.