Narrative:

Departure clearance was the lga 9 whitestone climb. On takeoff the heading showed approximately 10 degrees left of course. When turning right to 180 degrees the course appeared to be more than 60 degrees right of course when turning at acceleration altitude. Which was more than expected. Upon reaching 2.9 DME off the lga VOR the heading of 040 degrees was selected and the turn was started. The controller asked if we had started our turn which we responded to 'yes we are in the turn' and the lga DME showed 3.4 at this time. During the turn the controller asked us to increase our turn rate as we were further south than expected. We were then given a new heading of 360 degrees. We then were given direct col and then direct white. The heading indication for both the captain and first officer agreed; however the magnetic compass was about 25 degrees right of our current heading. The FMS showed us direct col with a wind indication of 119 KTS from the left. When the FMS showed us over col the controller gave us a heading of 250 degrees and said we were 2 mi east and past the col VOR. The controller then gave us direct white again and when selected; the FMS showed direct white; however; the controller's course to white was 15 more than the FMS indicated in the navigation mode. We then let the controller know we were going to use VOR's as our primary navigation. The controller gave us direct cyn VOR and after cyn a heading of 250 degrees. After cyn were given direct ric when able. While heading 250 degrees the FMS and VOR showed a better alignment around the vills intersection. When we asked the controller if vills was at 19 mi and 10 degrees left of course; the controller had 17 mi and 10 degrees left. It appeared at this time the alignment of the FMS had corrected itself.

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Original NASA ASRS Text

Title: EMB145 FLT CREW HAS A TRACK AND HDG DEV DURING LGA 1 DEP.

Narrative: DEP CLRNC WAS THE LGA 9 WHITESTONE CLB. ON TKOF THE HDG SHOWED APPROX 10 DEGS L OF COURSE. WHEN TURNING R TO 180 DEGS THE COURSE APPEARED TO BE MORE THAN 60 DEGS R OF COURSE WHEN TURNING AT ACCELERATION ALT. WHICH WAS MORE THAN EXPECTED. UPON REACHING 2.9 DME OFF THE LGA VOR THE HDG OF 040 DEGS WAS SELECTED AND THE TURN WAS STARTED. THE CTLR ASKED IF WE HAD STARTED OUR TURN WHICH WE RESPONDED TO 'YES WE ARE IN THE TURN' AND THE LGA DME SHOWED 3.4 AT THIS TIME. DURING THE TURN THE CTLR ASKED US TO INCREASE OUR TURN RATE AS WE WERE FURTHER S THAN EXPECTED. WE WERE THEN GIVEN A NEW HDG OF 360 DEGS. WE THEN WERE GIVEN DIRECT COL AND THEN DIRECT WHITE. THE HDG INDICATION FOR BOTH THE CAPT AND FO AGREED; HOWEVER THE MAGNETIC COMPASS WAS ABOUT 25 DEGS R OF OUR CURRENT HDG. THE FMS SHOWED US DIRECT COL WITH A WIND INDICATION OF 119 KTS FROM THE L. WHEN THE FMS SHOWED US OVER COL THE CTLR GAVE US A HDG OF 250 DEGS AND SAID WE WERE 2 MI E AND PAST THE COL VOR. THE CTLR THEN GAVE US DIRECT WHITE AGAIN AND WHEN SELECTED; THE FMS SHOWED DIRECT WHITE; HOWEVER; THE CTLR'S COURSE TO WHITE WAS 15 MORE THAN THE FMS INDICATED IN THE NAV MODE. WE THEN LET THE CTLR KNOW WE WERE GOING TO USE VOR'S AS OUR PRIMARY NAV. THE CTLR GAVE US DIRECT CYN VOR AND AFTER CYN A HDG OF 250 DEGS. AFTER CYN WERE GIVEN DIRECT RIC WHEN ABLE. WHILE HDG 250 DEGS THE FMS AND VOR SHOWED A BETTER ALIGNMENT AROUND THE VILLS INTXN. WHEN WE ASKED THE CTLR IF VILLS WAS AT 19 MI AND 10 DEGS L OF COURSE; THE CTLR HAD 17 MI AND 10 DEGS L. IT APPEARED AT THIS TIME THE ALIGNMENT OF THE FMS HAD CORRECTED ITSELF.

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