Date: 201205
Local time of day: 1801-2400
Location: ELP.Airport, TX
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ELP
ATC / advisory: TRACON ELP
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Distraction; Situational Awareness; Time Pressure; Workload; Communication Breakdown
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Other / Unknown
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Procedure; Human Factors; Environment - Non Weather Related
Primary problem: Procedure

Narrative: [We were] approaching El Paso from the north-northwest. At 13;000 FT MSL; cleared to MOLLY; thence ELP. Approach Control cleared us to MOLLY; then the Molly 2 RNAV Arrival. As pilot not flying; I read it back; and observed the First Officer select the MOLLY 2 RNAV Arrival; then go to the LEGS page. I see MOLLY at the top of the first page; concurred; then the First Officer executed. The First Officer said we were cleared to descend via the arrival. I didn't remember that; so queried Approach. They confirmed we were cleared to descend via the arrival. Before we initiated the descent from 13;000 FT; our current altitude; Approach said; 'Air Carrier XXXX; heading 110.' The First Officer selected 110 in the heading window; and selected 'Heading select'. As we were no longer on the RNAV arrival; I asked Approach Control what altitude we were cleared to descend to. They replied; 'Descend and maintain 6;000 FT.' We turned to heading 110; and began a descent to 6;000 FT. When we had initially switched to Approach Control and attempted to check in; they did not respond immediately. There were several other aircraft they were handling on the frequency; and it took two or three radio calls and maybe two minutes for them to acknowledge our checking in. When we arrived at the gate; the Ground Controller asked us to call. When I called; the Controller asked initially; 'Were you cleared to descend via the MOLLY 2 Arrival?' I said 'yes; but only after we verified the descend via clearance'. He then said; 'We saw your aircraft turn northeast after we gave you the clearance; that's why we gave you the vector; it was probably our mistake.' I was confused as to whether he had been concerned about our altitude or our lateral clearance; and asked him what this was about. He stated it was just the direction the aircraft initially turned that caused them to give a vector in lieu of the approach clearance and he wanted to verify what we understood. Better coordination between Center and Approach Control. We were given no indication; either on our flight plan; or from Center that we may expect an RNAV arrival. Approach Control had initially offered an RNAV (GPS) approach to a runway; after a lengthy check-in process. We declined; of course. We were then; hastily; it seemed; to be given the RNAV arrival; which caused a short term heavy cockpit load.


Second narrative: RNAV arrivals should not be issued late by ATC; nor should they be accepted by the crew if insufficient time is available to review; brief; and program the new arrival. In this case; the arrival was not complex; I had anticipated its being issued due to a preceding aircraft being assigned it; and it was manageable to comply with the clearance. However; this ATC clearance was basically pointless; and added needless complexity in close proximity to the field. In retrospect; I believe we would have been better off not accepting the RNAV arrival; but remaining with our original clearance or asking for vectors.


Synopsis: ELP TRACON issued an air carrier the MOLLY 2 STAR which caused confusion for the crew and a conflict for ATC but was in accordance with a ZAB letter of agreement.