CRJ200 first officer reports compass system malfunctions during initial climb. When passengers are a...

Narrative:

After departing; climbing through 9;000 ft we received an EFIS comp mon caution message. Flight manual directs pilots to slew compass to reliable side. It was apparent neither side was correct with the captain's; magnetic compass; and first officer's headings all different. We were cleared direct to a fix. Multiple attempts were made to match the headings with only temporary results. The captain elected to hand fly while the headings mismatched. While the FMS was taking us in a direct line; with the wind shift while hand flying the aircraft ended up 4 miles south of the original 'direct to' course. ATC called and asked if we were going direct; I told them we are having heading problems and asked how our heading looked. He told us 10 right and direct when able. On this trip we flew this same aircraft for 9 legs and did not have this problem on any other flight. In the past I have had similar events with speculation that cell phones left on may contribute to the heading problems. I made a PA asking our passengers to check their cell phones and make sure that they are off. Short of flying with both headings in dg we attempted to slew the compasses together again; and the EFIS comp mon was cleared with no further messages. Our flight attendant called and asked if that had helped; I said yes; what did you do? He stated he walked through the cabin and spoke to each of the 12 passengers. A passenger in row 9 had an iphone in the standby mode; not airplane mode or off. He showed the passenger how to turn the phone off fully. The flight continued to destination with no further problems.in my opinion and past experience the cell phone being on and trying to reconnect to towers on the ground; along with the location of row 9 to the instrumentation in the wing caused our heading to wander. The timing of the cell phone being turned off coincided with the moment where our heading problem was solved. Eight other flights in the same aircraft in two days span completed without a similar event.

Original NASA ASRS Text

Title: CRJ200 First Officer reports compass system malfunctions during initial climb. When passengers are asked to verify that all electronic devices are turned off the compass system returns to normal.

Narrative: After departing; climbing through 9;000 FT we received an EFIS COMP MON caution message. Flight Manual directs pilots to slew compass to reliable side. It was apparent neither side was correct with the Captain's; magnetic compass; and First Officer's headings all different. We were cleared direct to a fix. Multiple attempts were made to match the headings with only temporary results. The Captain elected to hand fly while the headings mismatched. While the FMS was taking us in a direct line; with the wind shift while hand flying the aircraft ended up 4 miles south of the original 'direct to' course. ATC called and asked if we were going direct; I told them we are having heading problems and asked how our heading looked. He told us 10 right and direct when able. On this trip we flew this same aircraft for 9 legs and did not have this problem on any other flight. In the past I have had similar events with speculation that cell phones left on may contribute to the heading problems. I made a PA asking our passengers to check their cell phones and make sure that they are off. Short of flying with both headings in DG we attempted to slew the compasses together again; and the EFIS COMP MON was cleared with no further messages. Our Flight Attendant called and asked if that had helped; I said yes; what did you do? He stated he walked through the cabin and spoke to each of the 12 passengers. A passenger in Row 9 had an iPhone in the standby mode; not airplane mode or off. He showed the passenger how to turn the phone off fully. The flight continued to destination with no further problems.In my opinion and past experience the cell phone being on and trying to reconnect to towers on the ground; along with the location of row 9 to the instrumentation in the wing caused our heading to wander. The timing of the cell phone being turned off coincided with the moment where our heading problem was solved. Eight other flights in the same aircraft in two days span completed without a similar event.

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.

Attributes
ACN	950259
Time
Date	201105
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb Climb
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Compass (HSI/ETC)
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 25 Flight Crew Total 2800 Flight Crew Type 2300
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types Flight Deck / Cabin / Aircraft Event Passenger Electronic Device

CRJ200 first officer reports compass system malfunctions during initial climb. When passengers are asked to verify that all electronic devices are turned off the compass system returns to normal.