Narrative:

I reviewed the route and was satisfied. However, I did not notice that the computer used sls NDB in ecuador, not sls VOR in peru. This caused an error of over 500 mi and reduced the required flight time by about 1 hour, causing a reduction in minimum fuel of about 12000 pounds. I discovered the discrepancy when I entered the flight plan in the GPS. However, we are not approved for GPS navigation and I believed I had entered the flight plan incorrectly. Since I was using the INS, I elected to depart on schedule and correct the GPS entry later. After leveloff we were busy until clear of cuban airspace. At this time I rechked my GPS waypoints. They were correct. I totaled the route mileage from the en route chart and it confirmed the error. I still could not believe the computer flight plan had errors. I entered mia direct spim in the INS and GPS and again confirmed the error. Upon computing arrival fuel at spim, I decided to divert to mpto and refuel. Contributing factors: 1) no member of the flight crew had previously flown this route. 2) the company dispatcher had not previously dispatched this route. 3) planning the flight direct from gyv to sls probably allowed the computer more leeway than filing an airway. 4) our crew members were provided with approach and area charts well in advance, but only 1 set of en route charts was provided and that was in the airplane. The fact that charts were not readily available inhibits advance planning and preparation. The flight landed safely at mpto and refueled. If it had continued without refueling, it would have landed at spim with about 9500 pounds of fuel. Supplemental information from acn 342521: the captain discovered the problem early in the flight and made the necessary changes with dispatch. The error was due to a NAVAID (an NDB) having the same 3 letter identify as a VOR 450 mi down the route only the NDB was 23 mi from the last fix. The captain then took immediate action. Due to this no danger was present. Callback conversation with reporter from acn 342521 revealed the following information: the reporter said that this was a route that was new to this flight crew who was flying a chartered load of freight for another air carrier. The other air carrier's dispatch and operations personnel did the flight planning and other preparation for the flight to spim and the reporter's flight crew entered the data into the DC8-73's INS system. Since no map was generated by the INS and the route mileage looked ok to the flight crew, they thought that the routing was correct. However, en route the captain, using a hand-held GPS, discovered the error. The flight crew found that a nearby NDB had the same 3 letter identify as the correct VOR fix some 500 NM away. Upon recalculating the mileage to their destination, the crew discovered that the route was approximately 500 NM further than planned. The reporter notified dispatch that the aircraft was going to make a fuel stop in pty due to the error. The delay was minimal. Later the flight crew was told that the same dispatch operations team had made the same error with another charter crew. Now that company has put a memo in the planning folder in an effort to preclude another error such as this.

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Original NASA ASRS Text

Title: A CHARTERED FREIGHT FLC DISCOVER ENRTE THAT THERE WAS AN ERROR IN THE FLT PLAN AND THE RTE WAS APPROX 500 NM LONGER THAN PLANNED. THE FLC DIVERTS TO A NEARBY ARPT FOR ADDITIONAL FUEL BEFORE COMPLETING THE FLT.

Narrative: I REVIEWED THE RTE AND WAS SATISFIED. HOWEVER, I DID NOT NOTICE THAT THE COMPUTER USED SLS NDB IN ECUADOR, NOT SLS VOR IN PERU. THIS CAUSED AN ERROR OF OVER 500 MI AND REDUCED THE REQUIRED FLT TIME BY ABOUT 1 HR, CAUSING A REDUCTION IN MINIMUM FUEL OF ABOUT 12000 LBS. I DISCOVERED THE DISCREPANCY WHEN I ENTERED THE FLT PLAN IN THE GPS. HOWEVER, WE ARE NOT APPROVED FOR GPS NAV AND I BELIEVED I HAD ENTERED THE FLT PLAN INCORRECTLY. SINCE I WAS USING THE INS, I ELECTED TO DEPART ON SCHEDULE AND CORRECT THE GPS ENTRY LATER. AFTER LEVELOFF WE WERE BUSY UNTIL CLR OF CUBAN AIRSPACE. AT THIS TIME I RECHKED MY GPS WAYPOINTS. THEY WERE CORRECT. I TOTALED THE RTE MILEAGE FROM THE ENRTE CHART AND IT CONFIRMED THE ERROR. I STILL COULD NOT BELIEVE THE COMPUTER FLT PLAN HAD ERRORS. I ENTERED MIA DIRECT SPIM IN THE INS AND GPS AND AGAIN CONFIRMED THE ERROR. UPON COMPUTING ARR FUEL AT SPIM, I DECIDED TO DIVERT TO MPTO AND REFUEL. CONTRIBUTING FACTORS: 1) NO MEMBER OF THE FLC HAD PREVIOUSLY FLOWN THIS RTE. 2) THE COMPANY DISPATCHER HAD NOT PREVIOUSLY DISPATCHED THIS RTE. 3) PLANNING THE FLT DIRECT FROM GYV TO SLS PROBABLY ALLOWED THE COMPUTER MORE LEEWAY THAN FILING AN AIRWAY. 4) OUR CREW MEMBERS WERE PROVIDED WITH APCH AND AREA CHARTS WELL IN ADVANCE, BUT ONLY 1 SET OF ENRTE CHARTS WAS PROVIDED AND THAT WAS IN THE AIRPLANE. THE FACT THAT CHARTS WERE NOT READILY AVAILABLE INHIBITS ADVANCE PLANNING AND PREPARATION. THE FLT LANDED SAFELY AT MPTO AND REFUELED. IF IT HAD CONTINUED WITHOUT REFUELING, IT WOULD HAVE LANDED AT SPIM WITH ABOUT 9500 LBS OF FUEL. SUPPLEMENTAL INFO FROM ACN 342521: THE CAPT DISCOVERED THE PROB EARLY IN THE FLT AND MADE THE NECESSARY CHANGES WITH DISPATCH. THE ERROR WAS DUE TO A NAVAID (AN NDB) HAVING THE SAME 3 LETTER IDENT AS A VOR 450 MI DOWN THE RTE ONLY THE NDB WAS 23 MI FROM THE LAST FIX. THE CAPT THEN TOOK IMMEDIATE ACTION. DUE TO THIS NO DANGER WAS PRESENT. CALLBACK CONVERSATION WITH RPTR FROM ACN 342521 REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT THIS WAS A RTE THAT WAS NEW TO THIS FLC WHO WAS FLYING A CHARTERED LOAD OF FREIGHT FOR ANOTHER ACR. THE OTHER ACR'S DISPATCH AND OPS PERSONNEL DID THE FLT PLANNING AND OTHER PREPARATION FOR THE FLT TO SPIM AND THE RPTR'S FLC ENTERED THE DATA INTO THE DC8-73'S INS SYS. SINCE NO MAP WAS GENERATED BY THE INS AND THE RTE MILEAGE LOOKED OK TO THE FLC, THEY THOUGHT THAT THE ROUTING WAS CORRECT. HOWEVER, ENRTE THE CAPT, USING A HAND-HELD GPS, DISCOVERED THE ERROR. THE FLC FOUND THAT A NEARBY NDB HAD THE SAME 3 LETTER IDENT AS THE CORRECT VOR FIX SOME 500 NM AWAY. UPON RECALCULATING THE MILEAGE TO THEIR DEST, THE CREW DISCOVERED THAT THE RTE WAS APPROX 500 NM FURTHER THAN PLANNED. THE RPTR NOTIFIED DISPATCH THAT THE ACFT WAS GOING TO MAKE A FUEL STOP IN PTY DUE TO THE ERROR. THE DELAY WAS MINIMAL. LATER THE FLC WAS TOLD THAT THE SAME DISPATCH OPS TEAM HAD MADE THE SAME ERROR WITH ANOTHER CHARTER CREW. NOW THAT COMPANY HAS PUT A MEMO IN THE PLANNING FOLDER IN AN EFFORT TO PRECLUDE ANOTHER ERROR SUCH AS THIS.

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.