Narrative:

This particular flight that I was PIC on originated out of dtw with chs being the destination airport. As we approached chs, we could see on our WX radar that storms were beginning to form at and around the chs airport. We were easily able to circumnav the storms that lay between us and the airport. As we got closer to chs, we could tell that a fairly large thunderstorm had just passed over the top of the chs airport. We were informed by ZJX that lightning had struck a radar site at the airport and that we should slow to 250 KTS, which we did. Shortly thereafter, we were told to contact charleston approach control. When we switched over to approach, it became very obvious that the controller was very busy. Not only was she dealing with the normal traffic load for a saturday, but she was also dealing with aircraft that were deviating to chs because of the WX. It was very difficult to check on with approach control because of the amount of traffic using the frequency. Xmissions were constantly being stepped on by other aircraft. We were finally able to check on and she eventually gave us a heading of northeast at 5000 ft. We flew this heading and altitude for awhile until it became obvious we would need to turn back towards the southwest because of a thunderstorm line in front of us. Because approach was so busy, it was nearly impossible to communicate this with approach. I was the PNF, therefore, I had control of the radios. I tried in vain to contact approach but my xmissions kept getting stepped on by other aircraft's xmissions. At this point we had no choice but to turn because of the storm that was in front of us by only a few mi. At this point I told the first officer to begin a right turn towards the southwest to avoid the line of thunderstorms. In the middle of the turn, I once again tried to contact approach and tell them we were in a right turn towards the southwest to avoid WX. The controller replied by reading a clearance 'turn right to 180 degree and descend to 3000 ft,' at which time I read back the clearance with no response from the controller. We then initiated a descent to 3000 ft. As we passed 4700 ft, the controller told us to return to 5000 ft. We descended to 4500 ft before promptly returning to 5000 ft as the controller instructed. When I queried the controller about our clearance to 3000 ft, she simply stated that we were only cleared to 5000 ft, and gave us a new heading away from the WX. The frequency was too busy to query her further and she never said another thing about the altitude deviation. TCASII never activated and it appeared there was no conflict with any traffic. Before we made our initial turn away from the WX, I did check the TCASII and did see that there were no aircraft showing up on our TCASII at our altitude of 5000 ft for the range of the TCASII (20 mi). We were eventually cleared for a visual approach to runway 15 at chs after we were vectored back around for the final approach course to runway 15. She then cleared us to tower frequency and we made a landing on runway 15. Looking back on our situation, it has become obvious that a chain of events led to our situation. Obviously with the thunderstorms in the area, and the lightning strike of the radar sight as well as the heavy traffic load, led to our misunderstanding. Because of so many aircraft on the same frequency it became nearly impossible to communicate with approach, especially when we really needed to avoid the line of thunderstorms. I believe what happened was that I inadvertently read back another aircraft's clearance. It seemed that the clearance she had just read was directed at us because just a second before I had requested a turn away from the WX, but that transmission was probably stepped on by another pilot. The readback that I gave to approach's clearance to a heading of 180 degrees and 3000 ft was also probably stepped on. Since approach did not respond to my readback, we thought it was the correct clearance. It would have been very prudent in a situation as busy as we were in to make sure that approach's clearance was directed at us and not another aircraft. Like I said earlier, it appeared that there was no conflict with any other aircraft and that there was very little time to ask the controller where the misunderstanding took place. She was very busy and did not seem very interested in pursuing the issue any further.

Related reports:

Google
 

Original NASA ASRS Text

Title: BA46 TURNED TO AVOID ENTRY INTO A TSTM. ATC RADAR WAS INOP AFTER BEING HIT BY LIGHTNING. COM WITH APCH CTL WAS NOT POSSIBLE BECAUSE OF TFC DENSITY, AND SIMULTANEOUS XMISSIONS.

Narrative: THIS PARTICULAR FLT THAT I WAS PIC ON ORIGINATED OUT OF DTW WITH CHS BEING THE DEST ARPT. AS WE APCHED CHS, WE COULD SEE ON OUR WX RADAR THAT STORMS WERE BEGINNING TO FORM AT AND AROUND THE CHS ARPT. WE WERE EASILY ABLE TO CIRCUMNAV THE STORMS THAT LAY BTWN US AND THE ARPT. AS WE GOT CLOSER TO CHS, WE COULD TELL THAT A FAIRLY LARGE TSTM HAD JUST PASSED OVER THE TOP OF THE CHS ARPT. WE WERE INFORMED BY ZJX THAT LIGHTNING HAD STRUCK A RADAR SITE AT THE ARPT AND THAT WE SHOULD SLOW TO 250 KTS, WHICH WE DID. SHORTLY THEREAFTER, WE WERE TOLD TO CONTACT CHARLESTON APCH CTL. WHEN WE SWITCHED OVER TO APCH, IT BECAME VERY OBVIOUS THAT THE CTLR WAS VERY BUSY. NOT ONLY WAS SHE DEALING WITH THE NORMAL TFC LOAD FOR A SATURDAY, BUT SHE WAS ALSO DEALING WITH ACFT THAT WERE DEVIATING TO CHS BECAUSE OF THE WX. IT WAS VERY DIFFICULT TO CHK ON WITH APCH CTL BECAUSE OF THE AMOUNT OF TFC USING THE FREQ. XMISSIONS WERE CONSTANTLY BEING STEPPED ON BY OTHER ACFT. WE WERE FINALLY ABLE TO CHK ON AND SHE EVENTUALLY GAVE US A HDG OF NE AT 5000 FT. WE FLEW THIS HDG AND ALT FOR AWHILE UNTIL IT BECAME OBVIOUS WE WOULD NEED TO TURN BACK TOWARDS THE SW BECAUSE OF A TSTM LINE IN FRONT OF US. BECAUSE APCH WAS SO BUSY, IT WAS NEARLY IMPOSSIBLE TO COMMUNICATE THIS WITH APCH. I WAS THE PNF, THEREFORE, I HAD CTL OF THE RADIOS. I TRIED IN VAIN TO CONTACT APCH BUT MY XMISSIONS KEPT GETTING STEPPED ON BY OTHER ACFT'S XMISSIONS. AT THIS POINT WE HAD NO CHOICE BUT TO TURN BECAUSE OF THE STORM THAT WAS IN FRONT OF US BY ONLY A FEW MI. AT THIS POINT I TOLD THE FO TO BEGIN A R TURN TOWARDS THE SW TO AVOID THE LINE OF TSTMS. IN THE MIDDLE OF THE TURN, I ONCE AGAIN TRIED TO CONTACT APCH AND TELL THEM WE WERE IN A R TURN TOWARDS THE SW TO AVOID WX. THE CTLR REPLIED BY READING A CLRNC 'TURN R TO 180 DEG AND DSND TO 3000 FT,' AT WHICH TIME I READ BACK THE CLRNC WITH NO RESPONSE FROM THE CTLR. WE THEN INITIATED A DSCNT TO 3000 FT. AS WE PASSED 4700 FT, THE CTLR TOLD US TO RETURN TO 5000 FT. WE DSNDED TO 4500 FT BEFORE PROMPTLY RETURNING TO 5000 FT AS THE CTLR INSTRUCTED. WHEN I QUERIED THE CTLR ABOUT OUR CLRNC TO 3000 FT, SHE SIMPLY STATED THAT WE WERE ONLY CLRED TO 5000 FT, AND GAVE US A NEW HDG AWAY FROM THE WX. THE FREQ WAS TOO BUSY TO QUERY HER FURTHER AND SHE NEVER SAID ANOTHER THING ABOUT THE ALTDEV. TCASII NEVER ACTIVATED AND IT APPEARED THERE WAS NO CONFLICT WITH ANY TFC. BEFORE WE MADE OUR INITIAL TURN AWAY FROM THE WX, I DID CHK THE TCASII AND DID SEE THAT THERE WERE NO ACFT SHOWING UP ON OUR TCASII AT OUR ALT OF 5000 FT FOR THE RANGE OF THE TCASII (20 MI). WE WERE EVENTUALLY CLRED FOR A VISUAL APCH TO RWY 15 AT CHS AFTER WE WERE VECTORED BACK AROUND FOR THE FINAL APCH COURSE TO RWY 15. SHE THEN CLRED US TO TWR FREQ AND WE MADE A LNDG ON RWY 15. LOOKING BACK ON OUR SIT, IT HAS BECOME OBVIOUS THAT A CHAIN OF EVENTS LED TO OUR SIT. OBVIOUSLY WITH THE TSTMS IN THE AREA, AND THE LIGHTNING STRIKE OF THE RADAR SIGHT AS WELL AS THE HVY TFC LOAD, LED TO OUR MISUNDERSTANDING. BECAUSE OF SO MANY ACFT ON THE SAME FREQ IT BECAME NEARLY IMPOSSIBLE TO COMMUNICATE WITH APCH, ESPECIALLY WHEN WE REALLY NEEDED TO AVOID THE LINE OF TSTMS. I BELIEVE WHAT HAPPENED WAS THAT I INADVERTENTLY READ BACK ANOTHER ACFT'S CLRNC. IT SEEMED THAT THE CLRNC SHE HAD JUST READ WAS DIRECTED AT US BECAUSE JUST A SECOND BEFORE I HAD REQUESTED A TURN AWAY FROM THE WX, BUT THAT XMISSION WAS PROBABLY STEPPED ON BY ANOTHER PLT. THE READBACK THAT I GAVE TO APCH'S CLRNC TO A HDG OF 180 DEGS AND 3000 FT WAS ALSO PROBABLY STEPPED ON. SINCE APCH DID NOT RESPOND TO MY READBACK, WE THOUGHT IT WAS THE CORRECT CLRNC. IT WOULD HAVE BEEN VERY PRUDENT IN A SIT AS BUSY AS WE WERE IN TO MAKE SURE THAT APCH'S CLRNC WAS DIRECTED AT US AND NOT ANOTHER ACFT. LIKE I SAID EARLIER, IT APPEARED THAT THERE WAS NO CONFLICT WITH ANY OTHER ACFT AND THAT THERE WAS VERY LITTLE TIME TO ASK THE CTLR WHERE THE MISUNDERSTANDING TOOK PLACE. SHE WAS VERY BUSY AND DID NOT SEEM VERY INTERESTED IN PURSUING THE ISSUE ANY FURTHER.

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.