Narrative:

During the approach phase to an ILS approach at bur, approach control cleared us to descend and maintain 4000 from our previously cleared 7000. After acknowledging and resetting the altitude alerter, I advised the captain I was contacting the FBO on our other communication radio. I listened to the captain receive a frequency change and after finishing my contact with the FBO I listened while the cap attempted to contact the next controller while we continued our descent. Due to the controller handling 2 or 3 VFR requests and 1 other IFR aircraft the captain was unable to check in after 4 tries. The captain leveled at 4000 and I checked in 'level 4000.' the controller immediately responded with 'you were cleared to 5000, turn right immediately heading 160 degrees.' the captain initiated the right turn and transmitted that we were cleared to 4000 ft. The controller replied, 'traffic 10 to 11 O'clock and 4 mi.' we saw the single engine and called traffic in sight and were given a new heading to intercept the final approach. During a phone conversation after the flight the supervisor of the facility told the captain the tape had us cleared to 5000. The captain and I both still believe we were cleared to 4000. There was no question, at the time, as to our altitude assignment. The problem, other than communication, which is most frequently the problem, was the controller's feeling that the VFR requests had a higher priority than the IFR aircraft in the approach phase of a flight. Our inability to check in and communicate our intent to descend to 4000 was critical in this incident. A turbojet aircraft descending at 2-3000 FPM and doing 250 KTS should have some priority over smaller VFR singles doing 100 KTS and descending or climbing at 500 to 1000 FPM.

Related reports:

Google
 

Original NASA ASRS Text

Title: CPR LTT ON APCH MIS-HEARS CLRNC, ALTDEV.

Narrative: DURING THE APCH PHASE TO AN ILS APCH AT BUR, APCH CTL CLRED US TO DSND AND MAINTAIN 4000 FROM OUR PREVIOUSLY CLRED 7000. AFTER ACKNOWLEDGING AND RESETTING THE ALT ALERTER, I ADVISED THE CAPT I WAS CONTACTING THE FBO ON OUR OTHER COM RADIO. I LISTENED TO THE CAPT RECEIVE A FREQ CHANGE AND AFTER FINISHING MY CONTACT WITH THE FBO I LISTENED WHILE THE CAP ATTEMPTED TO CONTACT THE NEXT CTLR WHILE WE CONTINUED OUR DSCNT. DUE TO THE CTLR HANDLING 2 OR 3 VFR REQUESTS AND 1 OTHER IFR ACFT THE CAPT WAS UNABLE TO CHK IN AFTER 4 TRIES. THE CAPT LEVELED AT 4000 AND I CHKED IN 'LEVEL 4000.' THE CTLR IMMEDIATELY RESPONDED WITH 'YOU WERE CLRED TO 5000, TURN R IMMEDIATELY HDG 160 DEGS.' THE CAPT INITIATED THE R TURN AND XMITTED THAT WE WERE CLRED TO 4000 FT. THE CTLR REPLIED, 'TFC 10 TO 11 O'CLOCK AND 4 MI.' WE SAW THE SINGLE ENG AND CALLED TFC IN SIGHT AND WERE GIVEN A NEW HDG TO INTERCEPT THE FINAL APCH. DURING A PHONE CONVERSATION AFTER THE FLT THE SUPVR OF THE FACILITY TOLD THE CAPT THE TAPE HAD US CLRED TO 5000. THE CAPT AND I BOTH STILL BELIEVE WE WERE CLRED TO 4000. THERE WAS NO QUESTION, AT THE TIME, AS TO OUR ALT ASSIGNMENT. THE PROB, OTHER THAN COM, WHICH IS MOST FREQUENTLY THE PROB, WAS THE CTLR'S FEELING THAT THE VFR REQUESTS HAD A HIGHER PRIORITY THAN THE IFR ACFT IN THE APCH PHASE OF A FLT. OUR INABILITY TO CHK IN AND COMMUNICATE OUR INTENT TO DSND TO 4000 WAS CRITICAL IN THIS INCIDENT. A TURBOJET ACFT DSNDING AT 2-3000 FPM AND DOING 250 KTS SHOULD HAVE SOME PRIORITY OVER SMALLER VFR SINGLES DOING 100 KTS AND DSNDING OR CLBING AT 500 TO 1000 FPM.

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.