Narrative:

Our flight was cleared fak direct brv, I was holding a magnetic course of 32 degree off fak with fak and brv needles centered on respective vors. Center advised us we were tracking approximately 55 degree radial off fak, which showed us east of intended course. We checked our magnetic compass while holding steady on 035 heading (both HSI's). I found magnetic compass to be swinging from 005 to 045. The captain made a PA, asking if anyone was using an electronic device. The F/a's found a young boy using an am/FM stereo tape player. We brought the device to the cockpit and found that whether I was on or off seemed to have no effect on our magnetic compass, it swung 45 degree in either case. Nevertheless, the captain asked the boy to discontinue using the radio/tape player, which the boy did. Upon arrival in syr, we asked avionics maintenance to check the magnetic compass and the HSI's and navigation radios. They found no defect and could not duplicate the problem. We had no further trouble. Callback conversation with reporter revealed the following: we pretty well determined that the am/FM tape player had nothing to do with the compass swinging. The magnetic compass has nothing to do with the compass system that steers the aircraft. We recycled the flux compasses 2 or 3 times and the system seemed to straighten itself out. We do not know how an error crept into the flux system. The whole incident was a mystery to us. We suspect gremlins were flying on the wings.

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Original NASA ASRS Text

Title: LGT IN FLT AT FL330 HAD MAGNETIC COMPASS SWING OF APPROXIMATELY 40 DEGREES IN ONE MINUTE CYCLES. CENTER ADVISED THEY WERE TRACKING 20 DEGREES OFF PROJECTED COURSE. AN AM-FM TAPE PLAYER WAS BEING OPERATED IN CABIN. TAPE PLAYER BROUGHT TO FLT DECK, ON OR OFF DID NOT AFFECT THE MAGNETIC COMPASS. FLUX COMPASSES WERE RECYCLED. PROBLEM DISAPPEARED. MAINTENANCE AT DESTINATION FOUND NO MALFUNCTION OF COMPASS SYSTEMS.

Narrative: OUR FLT WAS CLRED FAK DIRECT BRV, I WAS HOLDING A MAG COURSE OF 32 DEG OFF FAK WITH FAK AND BRV NEEDLES CENTERED ON RESPECTIVE VORS. CENTER ADVISED US WE WERE TRACKING APPROX 55 DEG RADIAL OFF FAK, WHICH SHOWED US E OF INTENDED COURSE. WE CHECKED OUR MAG COMPASS WHILE HOLDING STEADY ON 035 HDG (BOTH HSI'S). I FOUND MAG COMPASS TO BE SWINGING FROM 005 TO 045. THE CAPT MADE A PA, ASKING IF ANYONE WAS USING AN ELECTRONIC DEVICE. THE F/A'S FOUND A YOUNG BOY USING AN AM/FM STEREO TAPE PLAYER. WE BROUGHT THE DEVICE TO THE COCKPIT AND FOUND THAT WHETHER I WAS ON OR OFF SEEMED TO HAVE NO EFFECT ON OUR MAG COMPASS, IT SWUNG 45 DEG IN EITHER CASE. NEVERTHELESS, THE CAPT ASKED THE BOY TO DISCONTINUE USING THE RADIO/TAPE PLAYER, WHICH THE BOY DID. UPON ARRIVAL IN SYR, WE ASKED AVIONICS MAINT TO CHECK THE MAG COMPASS AND THE HSI'S AND NAV RADIOS. THEY FOUND NO DEFECT AND COULD NOT DUPLICATE THE PROBLEM. WE HAD NO FURTHER TROUBLE. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: WE PRETTY WELL DETERMINED THAT THE AM/FM TAPE PLAYER HAD NOTHING TO DO WITH THE COMPASS SWINGING. THE MAG COMPASS HAS NOTHING TO DO WITH THE COMPASS SYSTEM THAT STEERS THE ACFT. WE RECYCLED THE FLUX COMPASSES 2 OR 3 TIMES AND THE SYSTEM SEEMED TO STRAIGHTEN ITSELF OUT. WE DO NOT KNOW HOW AN ERROR CREPT INTO THE FLUX SYSTEM. THE WHOLE INCIDENT WAS A MYSTERY TO US. WE SUSPECT GREMLINS WERE FLYING ON THE WINGS.

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.