Narrative:

Takeoff runway 4R in dtw. At approximately 400 ft AGL commenced turn to ATC assigned heading of 020 degrees. At approximately 2500 ft MSL dtw departure control asked our heading and we responded in kind with 'heading 020.' nothing else was said by ATC or ourselves about a heading. After cleared on course and level at 10000 ft MSL ATC alerted us of a possible 'pilot deviation' and gave us a phone number to call upon landing in ZZZ. The captain called after arriving in ZZZ and the on-duty supervisor said they were processing the paperwork for a pilot deviation. He said that the separation between the preceding aircraft and ourselves was never less than 1000 ft vertically (no mention of horizontal separation); but that our track was 10 degrees left of that of the preceding aircraft assigned the same heading. It was noted by the crew while on the roll on runway 4R we received an 'EFIS comp mon' caution message and a heading flag. As directed by our SOP's concerning this specific 'nuisance message;' we continued our normal duties during this high work-load phase of flight. As stated above; when ATC queried our heading we replied with; and continued to fly a heading of 020 degrees; as the flying pilot's side and the standby heading indicator both matched at 020 degrees. Within the one minute or so that we had lifted off the runway until ATC asked our heading; and then cleared us on course; the heading flag and EFIS miscompare message cleared itself. This situation concerning a question of aircraft separation that was never in doubt could have been caused by a number of factors. 1) the magnetic anomaly near runway 4R in dtw caused the heading indicator(s) to read incorrectly; and although the crew flew the exact assigned heading; the track was different than the plane ahead. 2) dtw tower was operating with extreme efficiency in clearing traffic for takeoff and a safe window between departing aircraft was not emphasized. 3) human factors have lead (and for good reason) the company to create an SOP that considers this message a nuisance message while on the takeoff roll so that the crew can maintain a level of vigilance necessary to deal with more important concerns. Because there was neither time nor reason to correct the heading miscompare during the short time after beginning the takeoff roll until reaching 2500 ft; the aircraft could actually be tracking something other than desired. In an attempt to prevent this from happening again; the following could be applied. 1) as was the case for the preceding aircraft; an adequate time holding in position on runway 4R could allow for the detection and correction of a heading miscompare before the takeoff roll begins and the pilots are workload saturated. 2) if ATC observes an undesirable track at any time; the controller should not ask what heading is being flown; but rather assign a new and more desirable heading in the interest of safety.

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Original NASA ASRS Text

Title: A CRJ 200 departed DTW Runway 4R. During the takeoff roll an 'EFIS COMP MON' message alerted. The crew continued the takeoff on the assigned heading and was told by ATC that the flown track was 10 degrees in error.

Narrative: Takeoff Runway 4R in DTW. At approximately 400 FT AGL commenced turn to ATC assigned heading of 020 degrees. At approximately 2500 FT MSL DTW Departure Control asked our heading and we responded in kind with 'heading 020.' Nothing else was said by ATC or ourselves about a heading. After cleared on course and level at 10000 FT MSL ATC alerted us of a possible 'pilot deviation' and gave us a phone number to call upon landing in ZZZ. The Captain called after arriving in ZZZ and the on-duty Supervisor said they were processing the paperwork for a pilot deviation. He said that the separation between the preceding aircraft and ourselves was never less than 1000 FT vertically (no mention of horizontal separation); but that our track was 10 degrees left of that of the preceding aircraft assigned the same heading. It was noted by the crew while on the roll on Runway 4R we received an 'EFIS COMP MON' caution message and a heading flag. As directed by our SOP's concerning this specific 'nuisance message;' we continued our normal duties during this high work-load phase of flight. As stated above; when ATC queried our heading we replied with; and continued to fly a heading of 020 degrees; as the flying pilot's side and the standby heading indicator both matched at 020 degrees. Within the one minute or so that we had lifted off the runway until ATC asked our heading; and then cleared us on course; the heading flag and EFIS miscompare message cleared itself. This situation concerning a question of aircraft separation that was never in doubt could have been caused by a number of factors. 1) The magnetic anomaly near Runway 4R in DTW caused the heading indicator(s) to read incorrectly; and although the crew flew the exact assigned heading; the track was different than the plane ahead. 2) DTW Tower was operating with extreme efficiency in clearing traffic for takeoff and a safe window between departing aircraft was not emphasized. 3) Human Factors have lead (and for good reason) the company to create an SOP that considers this message a nuisance message while on the takeoff roll so that the crew can maintain a level of vigilance necessary to deal with more important concerns. Because there was neither time nor reason to correct the heading miscompare during the short time after beginning the takeoff roll until reaching 2500 FT; the aircraft could actually be tracking something other than desired. In an attempt to prevent this from happening again; the following could be applied. 1) As was the case for the preceding aircraft; an adequate time holding in position on Runway 4R could allow for the detection and correction of a heading miscompare before the takeoff roll begins and the pilots are workload saturated. 2) If ATC observes an undesirable track at any time; the controller should not ask what heading is being flown; but rather assign a new and more desirable heading in the interest of safety.

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.