Narrative:

We taxied into position on runway 13 at lga. We confirmed the correct runway and verified the magnetic headings (we had previously noted the yellow sign-check magnetic compass runway 13 is 132 prior to departure). I saw a red heading flag and subsequently pushed the fast slave button. That resulted in a heading change of 60 degrees. We were then cleared for takeoff. Knowing there was no way we could comply with the whitestone climb (turn to 180 until 2.5 DME then to 040) I told the non flying pilot that we can't do this (takeoff). The non flying pilot told ATC (lga tower) that we 'had to abort the takeoff.' we never pushed the power up. We had to add power to get off the runway. We exited at the reverse taxiway just prior to runway 22. We got off and the ahrs realigned itself. We discussed whether we needed to call the company for a new release. We referenced the fom and decided that; since we had determined the cause of our problem (mainly the magnetic anomalies associated with the metal pier that the very end of the taxiway and beginning of runway 13 comprise) that we did not need a new release and that we would call the on-duty chief pilot after the flight. Also there was no heating of the brakes other than normal taxiing. We decided that we would try to takeoff again and I would not try to slave the compasses for a small error. I would also try to find a good 'spot' to line up and wait that would not incite this problem with the ahrs. It was then that we saw all the emergency vehicles were rolling for us. We queried ground control and were told that this was SOP for lga. We told ground control that our headings had swung 60 degrees off course and that is why we couldn't takeoff. On the subsequent takeoff we lined up on the runway past the metal expansion joint (I figured that was where the pier ended and the earth began). Our headings were good; there were no flags and we could comply with the SID. We took off uneventfully. At our destination I called the on duty chief pilot shortly after landing and; in accordance with the fom; told him of our decision not to continue with the takeoff; the emergency vehicles and the heading anomalies. We agreed that this was a known issue for that runway that we were all aware of. I wouldn't use the phrase 'we had to abort the takeoff' if we never initiated the takeoff roll or takeoff power application.

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Original NASA ASRS Text

Title: A BE400's heading was affected by the LGA Runway 13 magnetic anomaly causing its heading to be off so dramatically that the takeoff was refuse while the problem was addressed.

Narrative: We taxied into position on Runway 13 at LGA. We confirmed the correct Runway and verified the magnetic headings (we had previously noted the yellow sign-check magnetic compass Runway 13 is 132 prior to departure). I saw a red HDG flag and subsequently pushed the fast slave button. That resulted in a heading change of 60 degrees. We were then cleared for takeoff. Knowing there was no way we could comply with the Whitestone Climb (turn to 180 until 2.5 DME then to 040) I told the non flying pilot that we can't do this (takeoff). The non flying pilot told ATC (LGA Tower) that we 'had to abort the takeoff.' We never pushed the power up. We had to add power to get off the runway. We exited at the reverse taxiway just prior to Runway 22. We got off and the AHRS realigned itself. We discussed whether we needed to call the company for a new release. We referenced the FOM and decided that; since we had determined the cause of our problem (mainly the magnetic anomalies associated with the metal pier that the very end of the taxiway and beginning of Runway 13 comprise) that we did not need a new release and that we would call the on-duty Chief Pilot after the flight. Also there was no heating of the brakes other than normal taxiing. We decided that we would try to takeoff again and I would not try to slave the compasses for a small error. I would also try to find a good 'spot' to line up and wait that would not incite this problem with the AHRS. It was then that we saw all the emergency vehicles were rolling for us. We queried Ground Control and were told that this was SOP for LGA. We told Ground Control that our headings had swung 60 degrees off course and that is why we couldn't takeoff. On the subsequent takeoff we lined up on the runway past the metal expansion joint (I figured that was where the pier ended and the earth began). Our headings were good; there were no flags and we could comply with the SID. We took off uneventfully. At our destination I called the on duty Chief Pilot shortly after landing and; in accordance with the FOM; told him of our decision not to continue with the takeoff; the emergency vehicles and the heading anomalies. We agreed that this was a known issue for that runway that we were all aware of. I wouldn't use the phrase 'we had to abort the takeoff' if we never initiated the takeoff roll or takeoff power application.

Data retrieved from NASA's ASRS site as of April 2012 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.