Narrative:

Our clearance was 'cleared as filed via the ACO2. Aco departure (akron two) climb and maintain 4000 ft; squawk XXXX.' the first officer entered the flight plan into the FMS correctly and I verified this at the gate prior to the turn around check being performed. The FMS listed our waypoints as veela; maars; sphre; and aco. This concurred with the ACO2.aco (akron two departure). After pushback; prior to the second engine start; there was a power interruption to the FMS and was quickly restored. After the second engine was started; and the after start check was performed we both verified that flight plan in the FMS was again correct. After takeoff we were given radar vectors; then told to proceed direct to the maars intersection. We selected direct maars in the FMS and proceeded on course without any problems. It was about 3 mi prior to approaching maars that I told the first officer that I would be off of the #1 radio to talk to operations. The first officer was backing up the route with the VOR. The aircraft started a turn toward aco. Something did not seem to be right we both immediately began investigating the issue. The first indication of there being issue was that the aco 329 degree radial was not showing any movement on the course deviation indicator. We then realized that the aircraft had turned at maars instead of sphre. It took about 60 seconds to figure this out; meanwhile we had deviated about 4 mi off of our route clearance. The ATC radio frequency was busy we were about to contact approach; however; they called us first and inquired. We told ATC we had preceded to cak and not sphre. ATC then re-cleared us to sphre. Luckily there was no conflict with any other traffic in the area. A few mins later ATC gave us a number to call. Once reaching cak; I called and the controller said that there have been several deviations at maars recently and wanted more information. Somehow sphre was deleted from the FMS as a waypoint. Even though we were backing up our route with the VOR we did not correct soon enough to prevent a deviation; thus causing us to turn about 19 mi too early. I also should have been much more aggressive when contacting ATC for a solution. Always; always; double-check your waypoints once in the air (after takeoff). Xchk your waypoints prior to each turn or fix.

Related reports:

Google
 

Original NASA ASRS Text

Title: AFTER A RADAR VECTOR TO MAARS INTXN AN FMS ACR ACFT ON THE DTW ACO2.ACO SID FLEW DIRECT ACO BYPASSING SPHRE. DURING PREFLT A POWER TRANSFER OCCURRED.

Narrative: OUR CLRNC WAS 'CLRED AS FILED VIA THE ACO2. ACO DEP (AKRON TWO) CLB AND MAINTAIN 4000 FT; SQUAWK XXXX.' THE FO ENTERED THE FLT PLAN INTO THE FMS CORRECTLY AND I VERIFIED THIS AT THE GATE PRIOR TO THE TURN AROUND CHK BEING PERFORMED. THE FMS LISTED OUR WAYPOINTS AS VEELA; MAARS; SPHRE; AND ACO. THIS CONCURRED WITH THE ACO2.ACO (AKRON TWO DEP). AFTER PUSHBACK; PRIOR TO THE SECOND ENG START; THERE WAS A PWR INTERRUPTION TO THE FMS AND WAS QUICKLY RESTORED. AFTER THE SECOND ENG WAS STARTED; AND THE AFTER START CHK WAS PERFORMED WE BOTH VERIFIED THAT FLT PLAN IN THE FMS WAS AGAIN CORRECT. AFTER TKOF WE WERE GIVEN RADAR VECTORS; THEN TOLD TO PROCEED DIRECT TO THE MAARS INTXN. WE SELECTED DIRECT MAARS IN THE FMS AND PROCEEDED ON COURSE WITHOUT ANY PROBS. IT WAS ABOUT 3 MI PRIOR TO APCHING MAARS THAT I TOLD THE FO THAT I WOULD BE OFF OF THE #1 RADIO TO TALK TO OPS. THE FO WAS BACKING UP THE RTE WITH THE VOR. THE ACFT STARTED A TURN TOWARD ACO. SOMETHING DID NOT SEEM TO BE RIGHT WE BOTH IMMEDIATELY BEGAN INVESTIGATING THE ISSUE. THE FIRST INDICATION OF THERE BEING ISSUE WAS THAT THE ACO 329 DEG RADIAL WAS NOT SHOWING ANY MOVEMENT ON THE COURSE DEV INDICATOR. WE THEN REALIZED THAT THE ACFT HAD TURNED AT MAARS INSTEAD OF SPHRE. IT TOOK ABOUT 60 SECONDS TO FIGURE THIS OUT; MEANWHILE WE HAD DEVIATED ABOUT 4 MI OFF OF OUR RTE CLRNC. THE ATC RADIO FREQ WAS BUSY WE WERE ABOUT TO CONTACT APCH; HOWEVER; THEY CALLED US FIRST AND INQUIRED. WE TOLD ATC WE HAD PRECEDED TO CAK AND NOT SPHRE. ATC THEN RE-CLRED US TO SPHRE. LUCKILY THERE WAS NO CONFLICT WITH ANY OTHER TFC IN THE AREA. A FEW MINS LATER ATC GAVE US A NUMBER TO CALL. ONCE REACHING CAK; I CALLED AND THE CTLR SAID THAT THERE HAVE BEEN SEVERAL DEVS AT MAARS RECENTLY AND WANTED MORE INFO. SOMEHOW SPHRE WAS DELETED FROM THE FMS AS A WAYPOINT. EVEN THOUGH WE WERE BACKING UP OUR RTE WITH THE VOR WE DID NOT CORRECT SOON ENOUGH TO PREVENT A DEV; THUS CAUSING US TO TURN ABOUT 19 MI TOO EARLY. I ALSO SHOULD HAVE BEEN MUCH MORE AGGRESSIVE WHEN CONTACTING ATC FOR A SOLUTION. ALWAYS; ALWAYS; DOUBLE-CHK YOUR WAYPOINTS ONCE IN THE AIR (AFTER TKOF). XCHK YOUR WAYPOINTS PRIOR TO EACH TURN OR FIX.

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.