CRJ900 flight crew reported during departure climb the Captain and First Officer's heading indications disagreed and neither matched ATC headings. The flight crew diverted and made a precautionary landing.
Synopsis
CRJ900 flight crew reported during departure climb the Captain and First Officer's heading indications disagreed and neither matched ATC headings. The flight crew diverted and made a precautionary landing.
Narrative
After departure from Runway XX on the ZZZZZ 6 RNAV SID; while climbing through about 4000 ft. in NAV mode and Autopilot on; ATC assigned us a left turn to heading 270 (as I recall) and climb to 12;000 ft. I selected HDG mode and bugged 270 heading. Soon after we started the turn; we received an EFIS COMP MON caution message with a HDG flag; as the Captain referred to the QRH procedure; ATC inquired about our heading starting that we did not comply with the assigned heading. We explained that we were having navigation issues; we were running the respective procedure and we requested a block of airspace while we sorted out the issue. ATC began to give us 'start turn and stop turn' instructions. Meanwhile; per the QRH procedure; we tried to determine the reliable heading source; but neither the Captain side; the First Officer (FO) side or magnetic compass indication was anywhere near each other or ATC's heading indication. At this point; I disengaged the Autopilot and we elected to deselect the flight directors and I began hand flying. A red MAG flag also displayed momentarily during the EFIS COMP MON issue. We leveled off at 10;000 ft. and we discussed possibility diverting to ZZZ. ATC continued to issue 'start turn and stop turn' instructions; we continued to cross check our heading indications against that of ATC; but they still did not match. Captain informed the flight attendants (FAs) of the situation and that we would most likely divert to ZZZ. We sent an ACARS message to Dispatch and Maintenance Control but did not get a response. Captain tried to communicate with Dispatch via ZZZ1 Radio but did not get through. After trying a second time; they could hear us but we could not hear them. Captain explained the situation and our intention to divert to ZZZ; Captain requested a gate in ZZZ and personnel to assist the passengers. By this point; the FO side heading began to match ATC's indication; and eventually Captain side did too. At this time we knew that we did not have the fuel remaining to continue to ZZZ2 as we had 8;000 pounds remaining. ZZZ ATC [requested priority handling] on our behalf. Captain confirmed the diversion with FA and made a passenger announcement regarding the situation/diversion. We set up for ZZZ ILS XXR and were vectored by ATC. The landing was uneventful.Heading indications were inaccurate causing us to not being able to comply with ATC's heading requests. We did our best to work with ATC to develop a safe alternative to internal heading indications by requesting 'start turn and stop turn' commands from ATC.
Second reporter narrative
After departure from Runway XX on the ZZZZZ 6 RNAV SID; while climbing through about 4000 ft. in NAV mode and Autopilot on; ATC assigned us a left turn to heading 270 (as I recall) and climb to 12;000 ft. The First Officer (FO) selected HDG mode and bugged 270 heading. Soon after we started the turn; we received an EFIS COMP MON caution message with a HDG flag; as I referred to the QRH procedure; ATC; simultaneously; inquired about our heading starting that we did not comply with the assigned heading.We explained that we were having navigation issues; we were running the respective procedure and we requested a block of airspace while we sorted out the issue.ATC began to give us 'turn and stop turn' instructions. Meanwhile; per the QRH procedure; we tried to determine the reliable heading source; but neither the Captain side; the FO side or magnetic compass indication was anywhere near each other or ATC's heading indication. At this point; the FO disengaged the Autopilot; we elected to deselect the flight directors and he hand flew. A red MAG flag also displayed momentarily during the EFIS COMP MON issue. We leveled off at 10;000 ft. and we discussed possibility diverting to ZZZ. ATC continued to issue 'turn and stop turn' instructions; we continued to cross check our heading indications against that of ATC; but they still did not match. I informed the flight attendants (FAs) of the situation and that most likely we would divert to ZZZ.We sent an ACARS message to Dispatch and Maintenance Control but did not get a response. I tried to communicate with dispatch via ZZZ1 Radio but did not get through. After trying a second time; they could hear us but we could not hear them. I explained the situation and our intention to divert to ZZZ; I requested a gate in ZZZ and personnel to assist the passengers. By this point; the FO side heading began to match ATC's indication; and eventually Captain side did match also. But even if we had elected to continue to ZZZ2; we did not have enough fuel at this point; 8;000 pounds remaining. ATC [requested priority handling] on our behalf. I confirmed the diversion with FA and I made a passenger announcement regarding the situation/diversion.We set up for ZZZ ILS XXR and were vectored by ATC. The landing was uneventful.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.