Flight Crew Air Transport Pilot (ATP)
Workload; Situational Awareness; Communication Breakdown; Distraction
ATC Issue All Types
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Environment - Non Weather Related; Human Factors
I was pilot flying and FO was pilot monitoring. Initially vectored and descended for ILS to runway 22L. Controller then changed the runway to 22R. We had already briefed 22R as the backup approach. FMC and radios were tuned for 22R and FO double checked that all frequencies and altitudes were set properly. Descended to 3000 feet and slowed to 170 knots perpendicular to ILS course for 22R. Controller was giving instructions to many aircraft in a rapid and uninterrupted stream. We were paying particular attention for our turn to intercept the localizer because of the extreme volume and rapidity of the transmissions by the controller. As we approached the extended course line for the localizer and it was becoming more apparent that we would overshoot the localizer the FO was trying to call the controller to ask for turn to intercept. There was never a break in the transmissions to allow him time to transmit. The next call we received from the controller was that we were cleared to intercept the localizer for 22R. I immediately began a  turn back towards the localizer as the FO acknowledged the call. The controller asked us why we had not turned to the intercept course we had previously been given and joined the localizer. FO replied that we had not been given a turn previously to join. At this point we joined the localizer intercepted the glide path and landed. Roll out and taxi to the gate were normal. On taxi-in ground gave me a number to call. After exiting aircraft I called the number given and controller supervisor called me back to discuss what had happened. His debrief to me was that another aircraft had answered the turn to final intended for us and the controller had acknowledged that response. I was told that since we had not acknowledged a turn to final and intercept we were not in the wrong. In speaking with the supervisor I stressed to him that we were keying for a turn to final and had not heard anything for us due to the tremendous amount of radio transmissions. He was satisfied with our explanation of the chain of events and ask that next time we ask for a turn to final from controller if necessary which of course we would have attempted if possible in this situation. He told me that no deviation was being considered.In the future if placed in this situation again and I am unable to ask controller for a turn to intercept due to extreme transmission volume I will execute the intercept myself since I am NORDO for all practical purposes. When able I will tell controller I have intercepted the localizer for the intended landing runway. I think this would be better than overshooting the localizer and intruding either to parallel runway airspace or other airport airspace.
I tried to ask for the turn to final but the frequency was extremely congested with no breaks in transmissions. I could not get a word in. Just after we passed through final; the controller told us to intercept final.
Arriving at destination at a traffic peak the flight crew of a B737NG failed to receive a timely turn to intercept the localizer for their approach. Immediately after passing through the final approach course; ATC called advising them to intercept; and asked them why they had failed to do as cleared. During a post flight interview it was determined that another flight had responded to their clearance and the error went undetected by both ATC and the reporters.