Narrative:

On this day we departed hpn and were given the westchester two departure; which we loaded into the flight plan on the FMS. Runway 16 was the active runway. This departure procedure requires a climb to 800 ft then a right turn to a heading of 320 and climb to 3000. I was first officer and pilot not flying. When we received takeoff clearance from the tower we competed the final items on the before takeoff checklist; part of which includes lights and pitot heat. The captain armed the navigation function of the flight director right after liftoff; which would allow the flight director/autopilot to fly the departure procedure then engaged the autopilot. As the airplane rolled wings level on a heading of 320 we checked in with new york departure; the controller asked us what our heading was and I replied '320' he said 'I show you on a heading of 360'. At that point both the captain and I cross checked all the heading indicators; the co-pilot's and standby indicators said 360 but the pilot's indicator showed 320; the autopilot was coupled to the pilot's side. The captain then disconnected the autopilot at that time just as we reached 3000 ft. While attempting to determine what our correct heading should be; the captain allowed the airplane to climb above our assigned altitude at which time he transferred control to me because my heading indicator seemed to be correct. I lowered the nose to regain the assigned altitude of 3000 and maintained a heading of 320. We determined later; the reason the captain's heading indicator was off; was when we received takeoff clearance; the captain accidentally switched the ahrs switch from automatic to manual instead of switching on the pitot heat; the switches are located close together. As we lined up for takeoff I said the pitot heat is not on; at which point he turned the heat on and returned the ahrs switch to normal. Apparently; the heading must have processed 40 degrees while we were climbing out and we did not notice.

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Original NASA ASRS Text

Title: CE525 First Officer reports checking in with departure heading 320 degrees; to be informed they are actually heading 360 degrees. A quick check revealed the Captain's AHRS was off by 40 degrees and during this time an altitude deviation also occurs.

Narrative: On this day we departed HPN and were given the Westchester Two Departure; which we loaded into the flight plan on the FMS. Runway 16 was the active runway. This departure procedure requires a climb to 800 FT then a right turn to a heading of 320 and climb to 3000. I was First Officer and pilot not flying. When we received takeoff clearance from the Tower we competed the final items on the before takeoff checklist; part of which includes lights and pitot heat. The Captain armed the NAV function of the flight director right after liftoff; which would allow the flight director/autopilot to fly the departure procedure then engaged the autopilot. As the airplane rolled wings level on a heading of 320 we checked in with New York departure; the Controller asked us what our heading was and I replied '320' he said 'I show you on a heading of 360'. At that point both the captain and I cross checked all the heading indicators; the co-pilot's and standby indicators said 360 but the pilot's indicator showed 320; the autopilot was coupled to the pilot's side. The Captain then disconnected the autopilot at that time just as we reached 3000 FT. While attempting to determine what our correct heading should be; the Captain allowed the airplane to climb above our assigned altitude at which time he transferred control to me because my heading indicator seemed to be correct. I lowered the nose to regain the assigned altitude of 3000 and maintained a heading of 320. We determined later; the reason the Captain's heading indicator was off; was when we received takeoff clearance; the Captain accidentally switched the AHRS switch from AUTO to MANUAL instead of switching on the pitot heat; the switches are located close together. As we lined up for takeoff I said the pitot heat is not on; at which point he turned the heat on and returned the AHRS switch to normal. Apparently; the heading must have processed 40 degrees while we were climbing out and we did not notice.

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.