Narrative:

Departed trm VFR with transponder code issued by palm springs approach. FMS originally set up with filed route 'dag; kepec 1 las.' once airborne ATC issued 'direct tnp then kepec 1 to las.' my first officer assured me FMS was set up properly. Upon arrival at tnp VOR aircraft made the turn towards dag VOR. Shortly thereafter ATC asked what was our filed route. First officer read back clearance to ATC. She asked us to turn north and that we were off course. I then reviewed the FMS and noticed it was not properly programmed. As I was making changes to the FMS ATC cleared us to FL210. I did not hear the altitude clearance from ATC. According to my first officer; ATC assigned FL220; then corrected herself and assigned FL210. My first officer had set FL220; but did not reset altitude alerter to FL210. ATC queried us as to our altitude. The first officer said FL220. She stated FL210 was assigned. We descended to FL210. The remainder of the flight was uneventful. Fatigue may have played a part. Possible actions to prevent another occurrence. 1) push ATC for a full clearance prior to departure. 2) personally review all FMS inputs to FMS by first officer. 3) first officer should have read back assigned altitude for my verification.

Related reports:

Google
 

Original NASA ASRS Text

Title: A CE560XL DEVIATED FROM ASSIGNED TRACK BECAUSE OF IMPROPERLY PROGRAMMED FMC; AND CLBED THROUGH ASSIGNED ALT BECAUSE OF CREW ERROR.

Narrative: DEPARTED TRM VFR WITH XPONDER CODE ISSUED BY PALM SPRINGS APCH. FMS ORIGINALLY SET UP WITH FILED RTE 'DAG; KEPEC 1 LAS.' ONCE AIRBORNE ATC ISSUED 'DIRECT TNP THEN KEPEC 1 TO LAS.' MY FO ASSURED ME FMS WAS SET UP PROPERLY. UPON ARR AT TNP VOR ACFT MADE THE TURN TOWARDS DAG VOR. SHORTLY THEREAFTER ATC ASKED WHAT WAS OUR FILED RTE. FO READ BACK CLRNC TO ATC. SHE ASKED US TO TURN N AND THAT WE WERE OFF COURSE. I THEN REVIEWED THE FMS AND NOTICED IT WAS NOT PROPERLY PROGRAMMED. AS I WAS MAKING CHANGES TO THE FMS ATC CLRED US TO FL210. I DID NOT HEAR THE ALT CLRNC FROM ATC. ACCORDING TO MY FO; ATC ASSIGNED FL220; THEN CORRECTED HERSELF AND ASSIGNED FL210. MY FO HAD SET FL220; BUT DID NOT RESET ALT ALERTER TO FL210. ATC QUERIED US AS TO OUR ALT. THE FO SAID FL220. SHE STATED FL210 WAS ASSIGNED. WE DSNDED TO FL210. THE REMAINDER OF THE FLT WAS UNEVENTFUL. FATIGUE MAY HAVE PLAYED A PART. POSSIBLE ACTIONS TO PREVENT ANOTHER OCCURRENCE. 1) PUSH ATC FOR A FULL CLRNC PRIOR TO DEP. 2) PERSONALLY REVIEW ALL FMS INPUTS TO FMS BY FO. 3) FO SHOULD HAVE READ BACK ASSIGNED ALT FOR MY VERIFICATION.

Data retrieved from NASA's ASRS site as of January 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.