Narrative:

Recurrent training was being conducted in moderate to heavy rain with continuous moderate turbulence. After landing at cae, following an ILS approach, I asked the training instructor if he wanted to fly the leg back to gmu from the right seat. He responded that he would enjoy the chance to get some 'stick' time. The flight proceeded normally to gmu in the above mentioned WX conditions. I was working the radios from the left seat and operating the WX radios. The approach controller at green issued what I thought was an approach clearance to gmu. We descended from 4000 ft toward 2500 ft and believed we were cleared for an ILS runway 36 at gmu. Passing 3000 ft I became suspicious, based on our FMS displaced location and ADF bearing to the LOM, that we had accepted an approach clearance for another aircraft with a very similar call sign. I queried the controller and he verified that the clearance was not for us. We climbed immediately to 4000 ft. I believe this incident was caused by our pilot role reversals during a time of high workload due to WX. Also the approach controller did not correct my incorrect readback of the approach clearance. Our situational awareness, FMS and ADF, helped us to question if we were indeed cleared for the approach.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLC OF AN LTT CPR TURBOPROP RESPONDED TO A CLRNC FOR ANOTHER ACFT WITH SIMILAR SOUNDING CALL SIGN. A DSCNT WAS STARTED ON AN ILS APCH TOO EARLY AND DOWN TO 1000 FT BELOW ASSIGNED ALT PRIOR TO CATCHING THEIR MISTAKE, VERIFYING THE MISTAKE WITH ATC, AND THEN RETURNING TO ASSIGNED ALT.

Narrative: RECURRENT TRAINING WAS BEING CONDUCTED IN MODERATE TO HVY RAIN WITH CONTINUOUS MODERATE TURB. AFTER LNDG AT CAE, FOLLOWING AN ILS APCH, I ASKED THE TRAINING INSTRUCTOR IF HE WANTED TO FLY THE LEG BACK TO GMU FROM THE R SEAT. HE RESPONDED THAT HE WOULD ENJOY THE CHANCE TO GET SOME 'STICK' TIME. THE FLT PROCEEDED NORMALLY TO GMU IN THE ABOVE MENTIONED WX CONDITIONS. I WAS WORKING THE RADIOS FROM THE L SEAT AND OPERATING THE WX RADIOS. THE APCH CTLR AT GREEN ISSUED WHAT I THOUGHT WAS AN APCH CLRNC TO GMU. WE DSNDED FROM 4000 FT TOWARD 2500 FT AND BELIEVED WE WERE CLRED FOR AN ILS RWY 36 AT GMU. PASSING 3000 FT I BECAME SUSPICIOUS, BASED ON OUR FMS DISPLACED LOCATION AND ADF BEARING TO THE LOM, THAT WE HAD ACCEPTED AN APCH CLRNC FOR ANOTHER ACFT WITH A VERY SIMILAR CALL SIGN. I QUERIED THE CTLR AND HE VERIFIED THAT THE CLRNC WAS NOT FOR US. WE CLBED IMMEDIATELY TO 4000 FT. I BELIEVE THIS INCIDENT WAS CAUSED BY OUR PLT ROLE REVERSALS DURING A TIME OF HIGH WORKLOAD DUE TO WX. ALSO THE APCH CTLR DID NOT CORRECT MY INCORRECT READBACK OF THE APCH CLRNC. OUR SITUATIONAL AWARENESS, FMS AND ADF, HELPED US TO QUESTION IF WE WERE INDEED CLRED FOR THE APCH.

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.