M-20 J (201) / Allegro
Flight Crew Instrument; Flight Crew Commercial
Flight Crew Last 90 Days 9; Flight Crew Total 450; Flight Crew Type 24
Human-Machine Interface; Confusion; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Aircraft; Environment - Non Weather Related
While on IFR Tower enroute [clearance]; route was listed as initial vectors. While being vectored around traffic; PIC was informed that aircraft heading was 15 degrees off ATC's requested heading. PIC verified heading indicator and compass using the runway heading prior to roll-out; and both instruments were accurate. After being informed of the PIC revised the heading indicator to reflect the 15 degree deviation; and didn't use the compass as a secondary check due to the reported error. ATC then told us to intercept V186 and resume navigation. LOC was verified via ident; and heading set for V186 return via V186. PIC was able to track using the LOC without issue. No further heading issue was encountered regarding the heading using the HI with the 15 degree corrective setting. PIC was effectively able to track the destination ILS LOC to a landing without incident. On investigation; after flight completion; PIC discovered that there was interference between an IPAD2 in close proximity to the compass due to magnets within the tablet itself; which was unknown to the PIC or the instructor on board; as well as other professional; and private pilots. The magnets in the IPAD2 caused the compass to deviate from an accurate heading by as much as 30 degrees; when in proximity to the IPAD.
The reporter stated that he was in IMC conditions with his instructor in the right seat when ATC notified him about the track deviation. The instructor was placing the iPad on the glareshield then in his lap while using the GPS for navigation. Neither pilot realized the iPad had magnets but he later discovered they are powerful enough to affect a compass. After landing when he placed the iPad on the glareshield and detected the compass deflection. ATC made no comments about his track deviation except to say he apparently had a navigation problem but did not pursue the deviation further.
[Report narrative contained no additional information.]
An iPad's internal magnets reportedly caused an IFR M201J 15 degree compass error; which ATC detected because of a track deviation. The compass error cause was not determined until after landing.