Narrative:

At approximately xa 12/90, flight was proceeding (as cleared) to destination nbg at FL370. Position was hrv 260 degree right/100 DME, heading 080 degrees. ATC (ZHU) cleared flight direct tibby. Aircraft commander had difficulty hearing the name and repeated the identify as he thought he had heard, beginning with a 'P.' ATC acknowledged that was correct and explained the turn would give the flight room to descend to nbg. Both aircraft commander and copilot looked on the high en route arwys chart for possible location of intersection or NAVAID stated by ATC, and aircraft commander found pebby intersection (aex 119 degree right/065 DME). Latitude and longitude was entered into the inertial navigation system, and heading change was made turning left approximately 45 degrees. ATC cleared flight to descent to FL240. As a x-chk to inertial heading to pebby, the aircraft commander wanted to use the msy VOR as reference, but noted msy was not being received by either VOR #1 or #2. New orleans TACAN was tuned to verify NAVAID status with no reception. ATC was called to verify that msy was off the air, to which they confirmed that it was. Aircraft commander made statement that flight was proceeding to pebby inertially. Copilot made statement to aircraft commander that this heading was taking the flight well out of its way with respect to its destination of nbg. As the flight was approaching FL311 descending at 1500 FPM, ATC cleared flight to maintain FL350. Also cleared to turn right to heading of 100 degrees. Autoplt was disengaged by copilot, to manually initiate the unexpected level-off and initiate the turn. ATC recommended that the inertial system should be checked out upon landing, because the aircraft was tracking approximately 030 degrees. Additionally, ATC told flight tibby's frequency was 112.0 and was approximately on heading of 100 degrees. Upon examining the low altitude arwys chart tibby (tbd) was found, tuned and flight proceeded as cleared direct tibby VOR west/O further incident. Supplemental information from acn 165202: cause: miscoms/improper pronunciation of clearance point between ATC and pilot. Correction: spell phonetically uncertain clearance points.

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Original NASA ASRS Text

Title: TRACK ERROR.

Narrative: AT APPROX XA 12/90, FLT WAS PROCEEDING (AS CLRED) TO DEST NBG AT FL370. POS WAS HRV 260 DEG R/100 DME, HDG 080 DEGS. ATC (ZHU) CLRED FLT DIRECT TIBBY. ACFT COMMANDER HAD DIFFICULTY HEARING THE NAME AND REPEATED THE IDENT AS HE THOUGHT HE HAD HEARD, BEGINNING WITH A 'P.' ATC ACKNOWLEDGED THAT WAS CORRECT AND EXPLAINED THE TURN WOULD GIVE THE FLT ROOM TO DSND TO NBG. BOTH ACFT COMMANDER AND COPLT LOOKED ON THE HIGH ENRTE ARWYS CHART FOR POSSIBLE LOCATION OF INTXN OR NAVAID STATED BY ATC, AND ACFT COMMANDER FOUND PEBBY INTXN (AEX 119 DEG R/065 DME). LAT AND LONGITUDE WAS ENTERED INTO THE INERTIAL NAV SYS, AND HDG CHANGE WAS MADE TURNING LEFT APPROX 45 DEGS. ATC CLRED FLT TO DSNT TO FL240. AS A X-CHK TO INERTIAL HDG TO PEBBY, THE ACFT COMMANDER WANTED TO USE THE MSY VOR AS REF, BUT NOTED MSY WAS NOT BEING RECEIVED BY EITHER VOR #1 OR #2. NEW ORLEANS TACAN WAS TUNED TO VERIFY NAVAID STATUS WITH NO RECEPTION. ATC WAS CALLED TO VERIFY THAT MSY WAS OFF THE AIR, TO WHICH THEY CONFIRMED THAT IT WAS. ACFT COMMANDER MADE STATEMENT THAT FLT WAS PROCEEDING TO PEBBY INERTIALLY. COPLT MADE STATEMENT TO ACFT COMMANDER THAT THIS HDG WAS TAKING THE FLT WELL OUT OF ITS WAY WITH RESPECT TO ITS DEST OF NBG. AS THE FLT WAS APCHING FL311 DSNDING AT 1500 FPM, ATC CLRED FLT TO MAINTAIN FL350. ALSO CLRED TO TURN RIGHT TO HDG OF 100 DEGS. AUTOPLT WAS DISENGAGED BY COPLT, TO MANUALLY INITIATE THE UNEXPECTED LEVEL-OFF AND INITIATE THE TURN. ATC RECOMMENDED THAT THE INERTIAL SYS SHOULD BE CHKED OUT UPON LNDG, BECAUSE THE ACFT WAS TRACKING APPROX 030 DEGS. ADDITIONALLY, ATC TOLD FLT TIBBY'S FREQ WAS 112.0 AND WAS APPROX ON HDG OF 100 DEGS. UPON EXAMINING THE LOW ALT ARWYS CHART TIBBY (TBD) WAS FOUND, TUNED AND FLT PROCEEDED AS CLRED DIRECT TIBBY VOR W/O FURTHER INCIDENT. SUPPLEMENTAL INFO FROM ACN 165202: CAUSE: MISCOMS/IMPROPER PRONUNCIATION OF CLRNC POINT BTWN ATC AND PLT. CORRECTION: SPELL PHONETICALLY UNCERTAIN CLRNC POINTS.

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.