Date: 201405
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: A310
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZZZ
ATC / advisory: CTAF ZZZ; Center ZZZ
Second aircraft: Skyhawk 172/Cutlass 172
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Human factors: Distraction; Situational Awareness; Communication Breakdown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Procedure; Airport; Human Factors
Primary problem: Ambiguous

Narrative: During the approach for the ILS we were directed by Center to call crossing [the IF 14 NM out] I felt that was a bit too close to the airport to be making the first traffic call; so I switched to CTAF and made my first traffic report just outside of [the IF]. I did not receive an immediate response but prior to returning to Center a C172 called that it was on a left base to [an intersecting runway]. I returned to Center and called crossing [the IF]. During this back and forth with the radio I noticed the Captain had fallen behind on the approach and was still fast and getting high on the glide path. I suggested lowering the gear to slowdown and increasing decent rate. 20-30 seconds later suggested speed brakes as well. The Captain called for Slats Extend and we received the Double Slat Failure ECAM's message. I called out the problem and we agreed to cycle the Slat Lever. This put us further behind getting to a stable approach. Also during this time I received a call from the C172 about our location. I responded we were about 12 miles out on final and as I extended the Slats. The C172 pilot responded that he had us in sight and had time to get one more approach in. Here is where I started to get very distracted. Our position relative to his Left Base put him over the city so I could not establish a visual with the C172. I was beginning to worry that he would be a conflict so I kept trying to acquire him visually. As we continued the approach the Captain was having a hard time slowing and inside of 1;000 feet AGL I realized we had not accomplished a Before Landing Checklist so I ran the checklist silently as the  was very task saturated and I was still trying to find the C172. As we approached 500 FT I knew we were not going to be stable but I was now not sure where the C172 was; but was pretty sure based on his last call that he was going to be crossing the runway center line during his low approach. At this point I began to feel task saturated and unsure of what to do as it was still night out and there was terrain on our left and right and I am thinking there is a C172 somewhere in front of us. We crossed 500 FT approximately 15-20 KTS fast; but the Captain was making the proper corrections. He got a little low on the glideslope approximately 200 FT; and I stated; 'We were getting low;' and he made the correction as the aircraft made a glideslope warning call. I made one last call on short final to the C172 and he responded something to the effect he was staying high with us in sight. We landed on speed with no problems however as we rolled out approx 1/2 down the runway the C172 crossed the center line at 500-1000 FT.My inexperience with uncontrolled airfields combined with the Captain falling behind during the approach created a situation we should not have gotten into. Upon realizing that the C172 was staying in the pattern we should have either directed him to remain clear of the airfield or gone around at that point until we could establish who had the proper clearance to use the facility. My initial thought was the C172 was going to land and not be a factor. I didn't think much of it until he said he had time to do 1 more approach. At this point I became distracted trying to verify his location and did  not back up the Captain properly during the approach resulting in the unstable condition and the aircraft in a  position where we had only the choice of either landing or going around with unknown traffic location in front  of us.




Synopsis: A310 First Officer describes a night ILS approach with the tower closed that is unstable from the beginning. The crew is distracted by CTAF procedures; terrain considerations; and a C172 making approaches to an intersecting runway. The approach is continued to landing as the C172 crosses down field on a low approach.