Narrative:

During my first week of flying in the northeast united states and third day of flying into lga, we were assigned the whitestone climb after departing runway 13 (which is the 175 degree heading until 2.5 DME and then a left turn to 040 degrees). After lining up on the runway and checking instruments and noting the airport sign saying check heading of 132.5 degrees we departed. After flying what we thought was the whitestone climb, we were given a heading and direct bdr when able. About 30 seconds later the controller asked what heading we were flying and we told him last assigned heading. At that point he said 'check your instruments' because he showed us needing to turn about 40 degrees to the right and said why our whitestone climb looked so different from normal. We asked to briefly level off and noted the magnetic compass and realized we were approximately 45 degrees off course. After resetting the ehsi's we continued our climb in the right direction. Then the controller advised us to change to the next controller after noting we were almost 8 mi off course. I believe what happened was a simultaneous precession of our instruments on rotation (ehsi's), because we never got a heading flag or any other type of flag when airborne. The contributing factors were definitely the fact that it was both crew members' first week in the northeast and the lack of known visual topographical visual points. Also it was the first time for both of us to do the whitestone climb and in hindsight, I remember thinking that the initial turn after takeoff was not as dramatic as I saw other aircraft making, but thought maybe they had received vectors after takeoff. Throughout the day we continued to monitor the ehsi's and magnetic compass more closely but did not see a recurring problem.

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Original NASA ASRS Text

Title: AN ACR LTT FLC, UNAWARE THAT THEY HAVE HAD AN ACFT EQUIP MALFUNCTION IN THEIR HDG SENSING, EXPERIENCES A HDG TRACK POS DEV. DEP CTLR GETS THEM ON A NEW HDG.

Narrative: DURING MY FIRST WK OF FLYING IN THE NE UNITED STATES AND THIRD DAY OF FLYING INTO LGA, WE WERE ASSIGNED THE WHITESTONE CLB AFTER DEPARTING RWY 13 (WHICH IS THE 175 DEG HDG UNTIL 2.5 DME AND THEN A L TURN TO 040 DEGS). AFTER LINING UP ON THE RWY AND CHKING INSTS AND NOTING THE ARPT SIGN SAYING CHK HDG OF 132.5 DEGS WE DEPARTED. AFTER FLYING WHAT WE THOUGHT WAS THE WHITESTONE CLB, WE WERE GIVEN A HDG AND DIRECT BDR WHEN ABLE. ABOUT 30 SECONDS LATER THE CTLR ASKED WHAT HDG WE WERE FLYING AND WE TOLD HIM LAST ASSIGNED HDG. AT THAT POINT HE SAID 'CHK YOUR INSTS' BECAUSE HE SHOWED US NEEDING TO TURN ABOUT 40 DEGS TO THE R AND SAID WHY OUR WHITESTONE CLB LOOKED SO DIFFERENT FROM NORMAL. WE ASKED TO BRIEFLY LEVEL OFF AND NOTED THE MAGNETIC COMPASS AND REALIZED WE WERE APPROX 45 DEGS OFF COURSE. AFTER RESETTING THE EHSI'S WE CONTINUED OUR CLB IN THE RIGHT DIRECTION. THEN THE CTLR ADVISED US TO CHANGE TO THE NEXT CTLR AFTER NOTING WE WERE ALMOST 8 MI OFF COURSE. I BELIEVE WHAT HAPPENED WAS A SIMULTANEOUS PRECESSION OF OUR INSTS ON ROTATION (EHSI'S), BECAUSE WE NEVER GOT A HDG FLAG OR ANY OTHER TYPE OF FLAG WHEN AIRBORNE. THE CONTRIBUTING FACTORS WERE DEFINITELY THE FACT THAT IT WAS BOTH CREW MEMBERS' FIRST WEEK IN THE NE AND THE LACK OF KNOWN VISUAL TOPOGRAPHICAL VISUAL POINTS. ALSO IT WAS THE FIRST TIME FOR BOTH OF US TO DO THE WHITESTONE CLB AND IN HINDSIGHT, I REMEMBER THINKING THAT THE INITIAL TURN AFTER TKOF WAS NOT AS DRAMATIC AS I SAW OTHER ACFT MAKING, BUT THOUGHT MAYBE THEY HAD RECEIVED VECTORS AFTER TKOF. THROUGHOUT THE DAY WE CONTINUED TO MONITOR THE EHSI'S AND MAGNETIC COMPASS MORE CLOSELY BUT DID NOT SEE A RECURRING PROB.

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.