Narrative:

A reclrnc had been issued by zan to proceed from st paul I (spy), G469, ordon, R580, oatis, direct ketar, otr-10, cvc. Captain looked up coordinates for waypoints along G469, and R580, and wrote them onto original flight plan form. After he inserted these coordinates into the INS, I checked all waypoints against flight plan. However, he wrote down and inserted the wrong latitude of north.5302.5 for onade instead of the correct latitude of north.5342.5. While in radar contact and approximately 50 mi east of onade. Anc ATC advised us we were south of course. All coordinates were checked again and it was discovered that the incorrect north latitude had been inserted after checking it against commercial chart. Latitude was updated, aircraft turned right to go direct to onade, and crossed onade on 328 degree radial 65 DME, approximately 3 mi south of course. All further coordinates were doublechked with both navigation chart and commercial chart. A contributing factor was that only 2 INS units were in use as the #3 is was inoperative at departure. This made it more difficult for 3 pilots to check coordinates and for back up. Also no blank flight plan forms were available thus making it more difficult to read rerte on existing flight plan. Suggest blank flight plan forms be stocked on aircraft, more diligence on part of all 3 crew members, and check all coordinates with chart particularly when rerte is involved.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACR WDB TRACK HDG DEV BECAUSE THE FLT CREW ENTERED THE WRONG LAT IN THE INS.

Narrative: A RECLRNC HAD BEEN ISSUED BY ZAN TO PROCEED FROM ST PAUL I (SPY), G469, ORDON, R580, OATIS, DIRECT KETAR, OTR-10, CVC. CAPT LOOKED UP COORDINATES FOR WAYPOINTS ALONG G469, AND R580, AND WROTE THEM ONTO ORIGINAL FLT PLAN FORM. AFTER HE INSERTED THESE COORDINATES INTO THE INS, I CHKED ALL WAYPOINTS AGAINST FLT PLAN. HOWEVER, HE WROTE DOWN AND INSERTED THE WRONG LATITUDE OF N.5302.5 FOR ONADE INSTEAD OF THE CORRECT LATITUDE OF N.5342.5. WHILE IN RADAR CONTACT AND APPROX 50 MI E OF ONADE. ANC ATC ADVISED US WE WERE S OF COURSE. ALL COORDINATES WERE CHKED AGAIN AND IT WAS DISCOVERED THAT THE INCORRECT N LATITUDE HAD BEEN INSERTED AFTER CHKING IT AGAINST COMMERCIAL CHART. LATITUDE WAS UPDATED, ACFT TURNED R TO GO DIRECT TO ONADE, AND CROSSED ONADE ON 328 DEG RADIAL 65 DME, APPROX 3 MI S OF COURSE. ALL FURTHER COORDINATES WERE DOUBLECHKED WITH BOTH NAV CHART AND COMMERCIAL CHART. A CONTRIBUTING FACTOR WAS THAT ONLY 2 INS UNITS WERE IN USE AS THE #3 IS WAS INOP AT DEP. THIS MADE IT MORE DIFFICULT FOR 3 PLTS TO CHK COORDINATES AND FOR BACK UP. ALSO NO BLANK FLT PLAN FORMS WERE AVAILABLE THUS MAKING IT MORE DIFFICULT TO READ RERTE ON EXISTING FLT PLAN. SUGGEST BLANK FLT PLAN FORMS BE STOCKED ON ACFT, MORE DILIGENCE ON PART OF ALL 3 CREW MEMBERS, AND CHK ALL COORDINATES WITH CHART PARTICULARLY WHEN RERTE IS INVOLVED.

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.