Date: 201305
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Troubleshooting; Situational Awareness; Distraction; Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; General Declared Emergency
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Shortly after departure the flight attendants reported visible smoke in the cabin. We declared an emergency and returned to the departure airport and made an uneventful landing on Runway 30L. We exited Runway 30L at Taxiway Kilo since crash-fire-rescue (CFR) equipment was standing by and blocking Taxiway Juliet. As we exited the runway the Tower Controller asked if we needed further assistance. My response was to ask if the CFR truck could see any smoke. The Tower had to repeat my request to the CFR truck [that] was apparently operating on a different frequency; causing a delay between communications and extra task-loading for the Tower Controller. While I was busy talking to the Tower; the Captain continued to taxi the aircraft and crossed Runway 30R which we visually confirmed was clear of traffic. The problem is that I do not remember receiving explicit instructions to cross Runway 30R. I am very confident that we did not receive a hold-short clearance because the Tower Controller was busy talking to the CFR truck; and I am sure I never read back a hold short instruction. I am not confident; however; that a crossing clearance was ever issued. By the time I realized that we were not going to stop; it was too late to say anything to the Captain that would have prevented us from entering Runway 30R. We may have been issued a crossing clearance and I simply missed it.  My expectation; however; was that the Captain was going to stop the aircraft short of Runway 30R.  After crossing; I said to the Captain 'Did we have clearance to cross' and he stated that he was sure that we had been given a crossing clearance. We proceeded to the gate uneventfully. Neither the Tower Controller or Ground Controller made any mention of any violation. Non-normal communications and communications occurring on different frequencies were factors in this event. Confusion arose from trying to communicate simultaneously with the Tower and with the CFR equipment while clearing the runway and before the aircraft was stopped. Under normal circumstances; the first communication we expect after landing is a clearance to cross or hold short of any parallel runway. In this case; the Tower and flight crew had the additional task of trying to determine if smoke was coming from the aircraft and if CFR action was immediately necessary. Crew task loading and perceptions were also factors. My task loading was probably higher than the Captain's because I was involved in non-normal communications with both the Tower and CFR equipment. My perception was that we were not cleared across Runway 30R while the Captain's perception was that we had indeed received clearance. Since the Tower and Ground Controllers never alerted us to any violation; the Captain's perception was probably correct. Tower task loading was also a factor. In the future; I would first confirm any taxi or hold-short instructions before answering additional questions from the Tower or engaging in non-normal communication with the Tower or CFR equipment. We normally brief our intended runway exit and taxi route as part of our descent briefing; but during an emergency I would recommend that we also brief our intention to stop the aircraft before communicating with CFR equipment.




Synopsis: An A320 crew declared an emergency and returned to the departure airport after flight attendants reported smoke in the cabin and in the after landing confusion may have crossed a parallel runway without clearance.