INCORRECT ONS LAT/LONG SET. POOR PRINTER AND DIGITS 3 AND 8 DIFFICULT TO DIFFERENTIATE.

Date: 1995-10 · Aircraft: B727-200

Anomalies: aircraft-equipment-problem-less-severe|deviation-track-heading-all-types|deviation-discrepancy-procedural-clearance

Synopsis

INCORRECT ONS LAT/LONG SET. POOR PRINTER AND DIGITS 3 AND 8 DIFFICULT TO DIFFERENTIATE.

Narrative

ON OUR PREFLT CHKS WE LOADED OUR ONS WAYPOINTS FROM OUR FLT PLAN. THE PRINTER WAS OF POOR TO FAIR QUALITY AND MOST OF THE 3'S COULD BE MISTAKEN FOR 8'S OR VICE VERSA. THAT MEANT THE FO AND I DOUBLE CHKED ALL THE WAYPOINTS WITH THE COMMERCIAL CHARTS; ESPECIALLY THOSE WITH 3'S AND 8'S IN THE LATITUDE/LONGITUDE. I CIRCLED THE OBVIOUSLY FLAWED DIGITS ALONG THE FLT PLAN. THE WEST LONGITUDE OF COLIN INTXN WAS ESPECIALLY TROUBLESOME. IT WAS PRINTED 33504N 97113W -- I WAS FOCUSING ON W LONGITUDE DUE TO THE POOR PRINTER QUALITY AND AS I DOUBLE CHKED THE ENTIRE LATITUDE/LONGITUDE FROM THE COMMERCIAL CHART I APPARENTLY SAW WHAT I WANTED TO SEE 33504N 79118W. THUS I CAUGHT ONE PRINTER ERROR BUT MISSED ANOTHER. THE ACTUAL LATITUDE/LONGITUDE FOR COLIN INTXN IS 38504N 79118W. MY FO XCHKED MY WORK AND MADE THE SAME ERROR. WE TRANSFERRED PWR FROM EXTERNAL PWR TO APU PWR DURING THE COURSE OF OUR PREFLT CHKS AND THEN MADE A TOTAL MILEAGE CHK OF THE ONS. THE FIRST CHK WAS 140 MI OFF. THAT SHOULD HAVE CLUED US IN BUT AFTER A PWR CHANGE THE ONS TAKES SOME TIME TO GET BACK UP TO SPD SO WE CHKED IT AGAIN AND GOT A READING WITHIN 15 MI OF THE FLT PLAN. 15 MI ON A 3 HR AND 32 MIN FLT PLAN IS CLOSE AFTER A PWR TRANSFER FOR ONS. AS WE GOT THE ALERT LIGHT PRIOR TO COLIN INTXN A FREQ CHANGE OCCURRED AND THE ACFT BEGAN ITS TURN TO A MORE SOUTHWESTERLY DIRECTION FOR LITTLE ROCK. WE HAD BEEN EXPERIENCING A HVY WIND FROM 250 DEG/95 KT UP UNTIL THAT POINT AND WHEN THE ONS CALLED FOR MORE OF A SOUTHERLY HDG WE WERE EACH THINKING MAYBE THE WIND HAD SHIFTED. ANOTHER FREQ CHANGE OCCURRED THEN ABOUT THE TIME WE REALLY QUESTIONED THE ONS ACCURACY AND DISCONNECTED IT AND BEGAN OUR TURN BACK TO A W-SW HDG WE GOT A CALL FROM CTR ASKING US OUR HDG. WE RESPONDED THAT WE WERE EXPERIENCING ONS PROBS AND THEY GAVE US A HDG FOR CHARLESTON; WV; AND FLT PLAN RTE. WE RE-ESTABLISHED OUR ONS AND DOUBLE CHKED COLIN INTXN AND DISCOVERED THE N LAT WAS IN ERROR N3350.4 WAS PRINTED ON THE FLT PLAN AND N3850.4 WAS THE ACTUAL LAT. OBVIOUSLY OUR PROFESSIONAL PRIDE WAS HURT BUT WE HAD CAREFULLY CORRECTED LAT/LONG FOR BWZ 40479N 74493W AND BARNS 42097N 7243.0W; ALONG OUR RTE OF FLT BUT HAD BOTH MISSED THIS ONE. OBVIOUSLY IN RETROSPECT I SHOULD HAVE ORDERED A NEW FLT PLAN FROM ANOTHER PRINTER SO THERE WOULD BE NO QUESTION IN ANY OF THE PRINTED MATERIAL WAYPOINTS. OUR INBOUND EQUIP WAS LATE AND WE WERE NOT RUSHING BUT MOVING THINGS ALONG AT A GOOD PACE. AGAIN IT WAS A NIGHT FLT AND COCKPIT LIGHTING MAY HAVE PLAYED A PART IN THE MISREADING OF THE LAT/LONG. NEXT TIME; WE ALL AGREE; THE PRINTER WILL BE LETTER PERFECT AND ALL OUR ENTRIES WILL BE ALSO.

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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.