Narrative:

Our facility was involved in a truly unbelievable hearback/readback incident. Aircraft X was nebound at FL390 over southern indiana. His destination was ZZZ. Aircraft Y was eastbound at FL410 landing YYY. Both aircraft were in the super high sector. The sector was quite busy; thus the similar call signs went unnoticed by both the radar controller and the associate controller (d-side); meaning the pilots were thus not warned. Aircraft Y was the first aircraft switched to sector 92. The aircraft Y pilot took the frequency change and this went unnoticed by both controllers and both sets of flight crews. The aircraft X then checks on frequency with the R92 controller. They initially thought something was not quite right; as the controller started to call the flight aircraft X; but then after looking at the aircraft Y data block corrected themselves and called the flight aircraft Y. Being called aircraft Y again went unnoticed by the aircraft X flight crew. It should be noted that the aircraft also checked on level at FL390; whereas the data block showed FL410. This again should have caught the attention of the R92 controller (a seasoned veteran) but it did not. Later; this aircraft Y flight was handed off and switched to the next in-house sector; R70; and again called aircraft Y. Aircraft X again answered and away he went. Aircraft X then checked on the R70 level at FL390. Again the controller did not catch the call sign or the altitude. To recap; the aircraft Y data block at FL410 has now been handed off twice and both times the flight crew of aircraft X answered. Both times this aircraft X flight crew checked on at FL390 and both times the receiving controller acknowledged the check-on by calling the flight aircraft Y. Again the aircraft X crew did not catch this either. To call this entire mix-up simply a hearback/readback incident is an understatement. It is utterly astounding that all the controllers involved and both sets of flight crews repeatedly answered for the other flight.

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Original NASA ASRS Text

Title: RADAR CTLR DESCRIBED READBACK HEARBACK ERROR INVOLVING SIMILAR ACFT NUMBERS; THAT INCLUDED SEVERAL CTLRS AND SECTORS; REPEATEDLY MISSED BY EVERYONE.

Narrative: OUR FACILITY WAS INVOLVED IN A TRULY UNBELIEVABLE HEARBACK/READBACK INCIDENT. ACFT X WAS NEBOUND AT FL390 OVER SOUTHERN INDIANA. HIS DEST WAS ZZZ. ACFT Y WAS EBOUND AT FL410 LNDG YYY. BOTH ACFT WERE IN THE SUPER HIGH SECTOR. THE SECTOR WAS QUITE BUSY; THUS THE SIMILAR CALL SIGNS WENT UNNOTICED BY BOTH THE RADAR CTLR AND THE ASSOCIATE CTLR (D-SIDE); MEANING THE PLTS WERE THUS NOT WARNED. ACFT Y WAS THE FIRST ACFT SWITCHED TO SECTOR 92. THE ACFT Y PLT TOOK THE FREQ CHANGE AND THIS WENT UNNOTICED BY BOTH CTLRS AND BOTH SETS OF FLT CREWS. THE ACFT X THEN CHKS ON FREQ WITH THE R92 CTLR. THEY INITIALLY THOUGHT SOMETHING WAS NOT QUITE RIGHT; AS THE CTLR STARTED TO CALL THE FLT ACFT X; BUT THEN AFTER LOOKING AT THE ACFT Y DATA BLOCK CORRECTED THEMSELVES AND CALLED THE FLT ACFT Y. BEING CALLED ACFT Y AGAIN WENT UNNOTICED BY THE ACFT X FLT CREW. IT SHOULD BE NOTED THAT THE ACFT ALSO CHKED ON LEVEL AT FL390; WHEREAS THE DATA BLOCK SHOWED FL410. THIS AGAIN SHOULD HAVE CAUGHT THE ATTN OF THE R92 CTLR (A SEASONED VETERAN) BUT IT DID NOT. LATER; THIS ACFT Y FLT WAS HANDED OFF AND SWITCHED TO THE NEXT IN-HOUSE SECTOR; R70; AND AGAIN CALLED ACFT Y. ACFT X AGAIN ANSWERED AND AWAY HE WENT. ACFT X THEN CHKED ON THE R70 LEVEL AT FL390. AGAIN THE CTLR DID NOT CATCH THE CALL SIGN OR THE ALT. TO RECAP; THE ACFT Y DATA BLOCK AT FL410 HAS NOW BEEN HANDED OFF TWICE AND BOTH TIMES THE FLT CREW OF ACFT X ANSWERED. BOTH TIMES THIS ACFT X FLT CREW CHKED ON AT FL390 AND BOTH TIMES THE RECEIVING CTLR ACKNOWLEDGED THE CHK-ON BY CALLING THE FLT ACFT Y. AGAIN THE ACFT X CREW DID NOT CATCH THIS EITHER. TO CALL THIS ENTIRE MIX-UP SIMPLY A HEARBACK/READBACK INCIDENT IS AN UNDERSTATEMENT. IT IS UTTERLY ASTOUNDING THAT ALL THE CTLRS INVOLVED AND BOTH SETS OF FLT CREWS REPEATEDLY ANSWERED FOR THE OTHER FLT.

Data retrieved from NASA's ASRS site as of May 2009 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.