Narrative:

On ferry deployment from goosebay to keflavik aircraft wound up excessively (40 NM) off course on second leg (ozn-kef) of overwater flight. Aircraft equipped with one omega and one ADF, 2 VOR's and one TACAN for navigation. Climbing out from goose, omega went dr several times prior to first fix, from which we intended to update. Immediate recalibration appeared effective and system still seemed to be reasonably accurate. When ozn ADF (greenland tip) was received our track appeared to be about 10 NM south of desired track. We homed the beacon and updated. The omega showed an approximately 40 NM error at that time. We tracked east out of ozn on the proper radial until reception was lost, then began to follow the omega toward our next 2 latitude/long fixes. After those we began getting kef DME at about 195 NM, but no azimuth until 160 NM at which time we began correcting toward the next fix (uniform, kef 280/120). Initial correction was 30 degrees for about 5 mins, then we went 90 degrees to the radial to correct back more rapidly. About 1 min after that turn iceland center informed us that we were 40 NM south of track and that he would be filing a navigation incident report on us. We informed him that we had been experiencing omega errors throughout the flight. Between ozn and that point the omega had gone dr another 3 or 4 times. Terminal error was 63 NM on landing. Basic cause of this incident was the gross malfunction of the omega. That was likely compounded by the gross misinformed of WX forecasters at both lfi and the reaffirmation at goose. They both forecast winds 220-250/25-35 KTS, where as actually winds were apparently southeast at maybe 30 KTS to greenland because of a low further north in the atlantic than anticipated. Then from greenland to iceland there appeared to be an unanticipated northwest wind due to high pressure area north of iceland. On the first leg of the flight the southeast wind appeared to counter some of the omega error, where as on the second leg (ozn-kef) it apparently compounded the error to blow us well right (south) of course.

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Original NASA ASRS Text

Title: CORP LTT GROSS NAVIGATION ERROR ON NORTH ATLANTIC ROUTE.

Narrative: ON FERRY DEPLOYMENT FROM GOOSEBAY TO KEFLAVIK ACFT WOUND UP EXCESSIVELY (40 NM) OFF COURSE ON SECOND LEG (OZN-KEF) OF OVERWATER FLT. ACFT EQUIPPED WITH ONE OMEGA AND ONE ADF, 2 VOR'S AND ONE TACAN FOR NAV. CLBING OUT FROM GOOSE, OMEGA WENT DR SEVERAL TIMES PRIOR TO FIRST FIX, FROM WHICH WE INTENDED TO UPDATE. IMMEDIATE RECALIBRATION APPEARED EFFECTIVE AND SYS STILL SEEMED TO BE REASONABLY ACCURATE. WHEN OZN ADF (GREENLAND TIP) WAS RECEIVED OUR TRACK APPEARED TO BE ABOUT 10 NM S OF DESIRED TRACK. WE HOMED THE BEACON AND UPDATED. THE OMEGA SHOWED AN APPROX 40 NM ERROR AT THAT TIME. WE TRACKED E OUT OF OZN ON THE PROPER RADIAL UNTIL RECEPTION WAS LOST, THEN BEGAN TO FOLLOW THE OMEGA TOWARD OUR NEXT 2 LAT/LONG FIXES. AFTER THOSE WE BEGAN GETTING KEF DME AT ABOUT 195 NM, BUT NO AZIMUTH UNTIL 160 NM AT WHICH TIME WE BEGAN CORRECTING TOWARD THE NEXT FIX (UNIFORM, KEF 280/120). INITIAL CORRECTION WAS 30 DEGS FOR ABOUT 5 MINS, THEN WE WENT 90 DEGS TO THE RADIAL TO CORRECT BACK MORE RAPIDLY. ABOUT 1 MIN AFTER THAT TURN ICELAND CENTER INFORMED US THAT WE WERE 40 NM S OF TRACK AND THAT HE WOULD BE FILING A NAV INCIDENT RPT ON US. WE INFORMED HIM THAT WE HAD BEEN EXPERIENCING OMEGA ERRORS THROUGHOUT THE FLT. BTWN OZN AND THAT POINT THE OMEGA HAD GONE DR ANOTHER 3 OR 4 TIMES. TERMINAL ERROR WAS 63 NM ON LNDG. BASIC CAUSE OF THIS INCIDENT WAS THE GROSS MALFUNCTION OF THE OMEGA. THAT WAS LIKELY COMPOUNDED BY THE GROSS MISINFORMED OF WX FORECASTERS AT BOTH LFI AND THE REAFFIRMATION AT GOOSE. THEY BOTH FORECAST WINDS 220-250/25-35 KTS, WHERE AS ACTUALLY WINDS WERE APPARENTLY SE AT MAYBE 30 KTS TO GREENLAND BECAUSE OF A LOW FURTHER N IN THE ATLANTIC THAN ANTICIPATED. THEN FROM GREENLAND TO ICELAND THERE APPEARED TO BE AN UNANTICIPATED NW WIND DUE TO HIGH PRESSURE AREA N OF ICELAND. ON THE FIRST LEG OF THE FLT THE SE WIND APPEARED TO COUNTER SOME OF THE OMEGA ERROR, WHERE AS ON THE SECOND LEG (OZN-KEF) IT APPARENTLY COMPOUNDED THE ERROR TO BLOW US WELL RIGHT (S) OF COURSE.

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