Date: 201406
Local time of day: 1801-2400
Location: LAX.Airport, CA
Flight conditions: VMC
Light: Night
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B LAX
ATC / advisory: TRACON SCT
Second aircraft: Commercial Fixed Wing
Reporter organization: Air Carrier
Reporter function: First Officer
Human factors: Workload; Time Pressure; Distraction; Confusion; Communication Breakdown; Situational Awareness
Second reporter function: Captain
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Other / Unknown
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Contributing factors: Airport; Environment - Non Weather Related; Human Factors; Procedure
Primary problem: Procedure

Narrative: Arriving into LAX on the SADDE6; we were initially told to expect a visual to [Runway] 24R. In the vicinity of SMO; we were told that the plan had changed and we would be given [Runway] 24L. Additional information was given that we would be in front of another aircraft arriving from the east landing [Runway] 24R.We asked for our sequence to determine how quickly we needed to descend on downwind; and were given a vague answer that we were number one for [Runway] 24L but number 3 for the north complex. The pilot flying kept our descent gradual as we interpreted this to mean that we would not be given an early base leg. SoCal Approach called out traffic at two o'clock; which we confirmed; and told us to follow that traffic; cleared for the visual [Runway] 24L. This represented a change in plans due to (1) being given the visual earlier than expected and (2) we were now following the traffic for [Runway] 24R that we were originally supposed to be in front of. In retrospect; we are very puzzled why SoCal chose to give the straight in traffic [Runway] 24R and the traffic on the northern (left) downwind [Runway] 24L; necessitating a crossing of flight paths. The geometry of the subsequent visual approach was worsened when SoCal gave us a 230 heading to intercept [Runway] 24L; just as the [Runway] 24R traffic began to disappear beneath our nose. We were given a directive simultaneously to the 230 heading saying 'don't pass that traffic.' The 230 vector was a very shallow 20 degree intercept to final that was going to delay the de-confliction in flight paths between us and the [Runway] 24R traffic. Before reaching the 230 heading; the pilot flying hesitated; realizing that the 230 heading was incompatible with the directive to not pass the [Runway] 24L traffic. The pilot flying was put in a situation at that point that required him hold off on his descent; check the aircraft heading back to something close to a 90-degree base and level the wings; delaying the turn to final in order to de-conflict laterally and vertically with the [Runway] 24R traffic. While there were no TA indications from the TCAS; we felt that our flight paths were not de-conflicted enough.All this confusion came on top of the frequency change to Tower. After checking in with Tower; we were asked to confirm that we were turning back to final for [Runway] 24L as our flight path had overshot the localizer due to the maneuver to keep sight and de-conflict with the [Runway] 24R traffic. We already had the correction in and confirmed as much with the Tower. The overshoot was minor but was a result of the pilot flying and pilot monitoring agreement that the 230 heading was going to result in an unsafe merging of flight paths inside 1;000 FT on final. Despite the confusion; the pilot flying had the aircraft stabilized at 1;000 FT and we landed uneventfully from that point on. SoCal should NOT issue visual approach clearances at night that require aircraft to cross flight paths relatively close to the airport. As a crew; we should have challenged the change in plans issued by ATC. It would have been more appropriate from the aircrew perspective at least to for us to land on [Runway] 24R and the straight in traffic to land on [Runway] 24L. There are too many aircraft in the vicinity of LAX and too much cultural lighting on the ground to visually de conflict in the high task loading environment of a relatively in close base leg visual approach at night. The runway assignments and vectors resulted in unsafe situation on visual approach.


Second narrative: Radio congestion prevented challenging SoCal. Pilot flying stopped turn to 230 and turned back toward a 90-degree intercept while staying almost level to avoid traffic to [Runway] 24R. Conflict traffic appeared to pass directly underneath us. Both pilot flying and pilot not flying were busy focused on flying the aircraft and de-conflicting traffic so no communication was made to SoCal about our problem and actions. Approach then instructed frequency change to Tower. The traffic de-conflicting maneuver resulted in a slight overshoot on the turn to final to [Runway] 24L; which caused Tower to voice concern with traffic on the south complex. Aircraft was stabilized by 1;000 FT and remainder of flight was uneventful.Given the same situation; I will not call traffic in sight because of unsafe directions from Approach Control.


Synopsis: A flight crew on the LAX SADDE 6 were initially assigned Runway 24R but changed to Runway 24L because of traffic. SCT issued a crosswind vector resulting in a traffic conflict nearing an overflight so the crew deviated to clear the conflict and slightly overshot after the turn back to Runway 24L.