CRJ-200 flight crew reported a need for delay vectors to burn fuel and when cleared back to a fix for the approach they were below the MIA for the area resulting in ATC issuing a low altitude alert; climb; and vector back on course.
Synopsis
CRJ-200 flight crew reported a need for delay vectors to burn fuel and when cleared back to a fix for the approach they were below the MIA for the area resulting in ATC issuing a low altitude alert; climb; and vector back on course.
Narrative
CA- Pilot flying. FO- Pilot monitoring. Prior to being cleared for the RNAV XX into ZZZ from ZZZZZ crew realized current fuel load and expected burn to landing would result in touching down overweight. To alleviate this threat the crew descended early from cruise; slowed and once on the approach extended partial flaps. After crossing ZZZZZ1 the crew determined there still needed to be excess fuel burned to avoid an overweight landing so radar vectors were requested off the approach southbound and the intention of returning back to ZZZZZ1 to continue the approach was made clear and understood by ATC. A clearance of turn left heading 220 and descend and maintain 10000. FO heard and read back turn left heading 220 and descend and maintain 10000. No correction was given by ATC. CA set 10000 and began descending. ATC then informed the crew that they could stay on that heading until they advised ATC they were ready to proceed back to ZZZZZ1 and to expect a left turn. Once an acceptable fuel load was reached FO requested a left turn direct ZZZZZ1. This left turn was given by ATC. Well past heading 180 into the left turn ATC gave crew a terrain warning and instructed them to turn to a heading of 180 and seem confused why they were at 10000 and instructed the crew to climb to 12000 which was complied with immediately by the crew. This perceived confusion from ATC and the immediate climb to 12000 indicates a possible altitude deviation and is the reason for this report though crew believes they were cleared to 10000 and complied with that clearance. The crew was told to keep their own terrain clearance which was complied with. Crew queried ATC to confirm they wanted them to stop the left turn and turn back to the right to a heading of 180. ATC confirmed this and the crew complied. Once at an altitude of 12000 and heading 180 crew continued to approach and the remainder of the flight was completed without incident.Cause: The primary cause of this event was the FO potentially mishearing ATC clearance to descend to 12000 but rather heard and readback to descend to 10000. Additionally; if ATC would have corrected the possibly incorrect readback or noticed the crew descending below 12000 this would have prevented the descent to 10000 and the ATC terrain warning when cleared direct ZZZZZ1. Also; once seeing the aircraft at 10000 a right turn towards the airport and away from the terrain would seem to have been a better choice.Suggestions: In the future FO will be more careful with accurately hearing ATC instructions. Another option for the crew would have been to ask for a hold over a fix on the approach to burn fuel rather than being vectored off. Additionally; once on the vector the crew could have asked for the visual to either XX or XY given the visual contact with the airport. However; the intent of proceeding back to ZZZZZ1 to rejoin the approach was to provide an environment more conducive to a stable approach given this particular airport and it being at night. To avoid recurrences from ATC perspective it would be helpful to listen closer to verify crews are giving accurate read backs and aircraft are subsequently doing what they were instructed.
Second reporter narrative
Cleared for RNAV XX ZZZZZ. Noted after crossing ZZZZZ1 that fuel despite earlier efforts was still too much. Asked for and received vectors south to burn fuel with the intention of returning to the approach over ZZZZZ1. We proceeded to 10000 on 220 heading with instructions to let ATC know when we would be able to return. We were cleared initially a left turn back to ZZZZZ1. Then ATC asked if we were going to climb to 12000. We responded that we were at 10 and would climb to 12. We were established in the left turn; then told to turn right to a 180 heading. We were close to the field; asked for a visual; landed without incident.Cause: both crew believed we were cleared to 10. We were surprised that we weren't to be at 10. Somehow communication broke between clearance received; clearance read back; not challenged by ATC.Suggestions: In this case I thought we were cleared to 10. We weren't challenged by ATC until we had been level at 10; and then we called ready to return ZZZZZ1. High area of vulnerability; with changes to an approach. A lot going on; and apparently a clearance to descend was incorrectly read back and missed by all parties.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.