Narrative:

On approach we were put on a heading of 210 degrees at 3000' in the process of being set up for a parallel visibility approach to runway 30R at lambert field, st louis. We had been asked to identify the aircraft making the visibility to 30L. The procedure at this airport is after the traffic is seen and the runway is visible, you are cleared for the approach. At this point it began to fall apart. The approach controller got very busy and I could not get through to him on the radio. We were closing with the aircraft Y for the other runway and it was getting uncomfortable as we were on a 90 degree intercept to him and closing fast. I can only speculate the first officer who was flying saw the closure and feeling as uncomfortable as I got 500' below the assigned altitude. When we finally were able to make radio contact with approach, he immediately asked our altitude and told us had given us a 240 degree heading. We were never in receipt of this transmission. We were subsequently cleared for a visibility and went in and landed. Supplemental information from acn 154639: on the 210 degree heading we observed traffic at 10 O'clock on approximately 1 310 degree heading and at our altitude. I was flying the aircraft and told the captain 'runway 30R in sight,' so he could relay to approach get a clearance for a visibility approach and avoid any conflict with traffic. As I was descending the captain said to increase the rate of descent: 'keep it coming down.' after he transmitted to approach, 'field in sight,' he made a reference to a visibility approach which I understood as cleared for visibility. Therefore, continued descent below 3000' MSL.

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Original NASA ASRS Text

Title: MISSED COM AND TRAFFIC CONCERNS CONTRIBUTE TO ALT OVERSHOOT IN DESCENT.

Narrative: ON APCH WE WERE PUT ON A HDG OF 210 DEGS AT 3000' IN THE PROCESS OF BEING SET UP FOR A PARALLEL VIS APCH TO RWY 30R AT LAMBERT FIELD, ST LOUIS. WE HAD BEEN ASKED TO IDENT THE ACFT MAKING THE VIS TO 30L. THE PROC AT THIS ARPT IS AFTER THE TFC IS SEEN AND THE RWY IS VISIBLE, YOU ARE CLRED FOR THE APCH. AT THIS POINT IT BEGAN TO FALL APART. THE APCH CTLR GOT VERY BUSY AND I COULD NOT GET THROUGH TO HIM ON THE RADIO. WE WERE CLOSING WITH THE ACFT Y FOR THE OTHER RWY AND IT WAS GETTING UNCOMFORTABLE AS WE WERE ON A 90 DEG INTERCEPT TO HIM AND CLOSING FAST. I CAN ONLY SPECULATE THE F/O WHO WAS FLYING SAW THE CLOSURE AND FEELING AS UNCOMFORTABLE AS I GOT 500' BELOW THE ASSIGNED ALT. WHEN WE FINALLY WERE ABLE TO MAKE RADIO CONTACT WITH APCH, HE IMMEDIATELY ASKED OUR ALT AND TOLD US HAD GIVEN US A 240 DEG HDG. WE WERE NEVER IN RECEIPT OF THIS XMISSION. WE WERE SUBSEQUENTLY CLRED FOR A VIS AND WENT IN AND LANDED. SUPPLEMENTAL INFO FROM ACN 154639: ON THE 210 DEG HDG WE OBSERVED TFC AT 10 O'CLOCK ON APPROX 1 310 DEG HDG AND AT OUR ALT. I WAS FLYING THE ACFT AND TOLD THE CAPT 'RWY 30R IN SIGHT,' SO HE COULD RELAY TO APCH GET A CLRNC FOR A VIS APCH AND AVOID ANY CONFLICT WITH TFC. AS I WAS DSNDING THE CAPT SAID TO INCREASE THE RATE OF DSNT: 'KEEP IT COMING DOWN.' AFTER HE XMITTED TO APCH, 'FIELD IN SIGHT,' HE MADE A REF TO A VIS APCH WHICH I UNDERSTOOD AS CLRED FOR VIS. THEREFORE, CONTINUED DSNT BELOW 3000' MSL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.