A319
Flight Crew Air Transport Pilot (ATP)
Confusion; Communication Breakdown; Workload
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Chart Or Publication; Human Factors; Procedure
ATC clearance was...direct SANDHILLS VOR (SDZ) and join the MALNR ONE RNAV Arrival with the RWY 5L/R transition. The MALNR ONE RNAV Arrival is an Optimum Profile Descent arrival. We were on the published course at 15;000 FT MSL. Just prior to SDZ VOR; Washington Center re-cleared us direct MALNR Intersection. The Controller included in the clearance; 'Cleared to descend via the MALNR ONE Arrival.' At this point we were just abeam the SDZ VOR and no more than 5 miles west of the published arrival course between SDZ and MALNR Intersection. I programmed the FMGC to go direct to MALNR and announced that I was about to begin the descent. The restriction over MALNR is to cross at 250 KTS and at or above 11;000 FT. The distance to MALNR was less than 20 miles and I wanted to ensure that I captured the descent profile. The pilot not flying voiced concern that we should not begin descent as we were no longer on a published segment of the profile descent procedure. I stated that I believed we were able to descend and activated a managed descent. The pilot not flying suggested we call ATC for clarification and we agreed that we should. The pilot not flying asked the Controller to confirm that we were cleared to descend via the arrival at that exact time. The Controller responded with affirmative. I felt that we were correct in beginning the descent. The descent; approach and landing into RDU were completed without event. After arriving at the gate and preparations for the next flight began; I called the RDU Clearance Delivery Controller and told him about the confusion we experienced when issued the 'descend via' clearance. I asked him if we were correct to begin descent while on the direct routing or should we have remained at 15;000 FT until crossing MALNR Intersection and then began the descent. He responded with 'I'm not sure. Let me ask some other controllers.' He later responded with a consensus of opinion that we were cleared direct to a fix on the profile descent but that the new direct routing took us off of the published arrival course. Since we were no longer on a published segment of the arrival; we should not have begun descent until we re-intercepted the published arrival. He went on to say that the Center Controller should have issued us a new descent clearance to cross the MALNR fix at a specific altitude and/or that the 'descend via' clearance was to commence after crossing the MALNR fix. The event occurred because [of] a misleading and misunderstood clearance; inexperience with the new optimum profile procedures; and a failure to use my external resources. These Optimum Profile Descent procedures are complex and we don't have a lot of experience with them. Likewise; the controllers are learning how to use them as well. I believed that since we were issued the 'direct to' clearance and the 'descend via' clearance in the same transmission and because we were so close to the routing and the MALNR fix that we were legal to begin descent. I let the close proximity of the airport and the task loading of the arrival; approach and landing push me into a bad decision. I should have listened to the pilot not flying and insisted on a clarification from the Center Controller of the instructions.
[Narrative 2 contained no additional information.]
An Air Carrier flight crew; given a vector direct to MALNR and cleared to 'descend via' the MALNR RNAV arrival to RDU; descended to the published crossing altitude for MALNR. Post-flight call to ATC revealed that descent was not authorized since they were not on a published segment of the arrival.