On 29 October 2021, a Bombardier CRJ900 lined up and began a night takeoff at San Diego aligned with the left runway edge lights instead of the runway centreline damaging both edge lights and the aircraft wing and landing gear. The pilots stated they had been unaware of their error until aircraft damage was found after landing despite returning to the runway after about a third of their takeoff roll. This apparent conflict between the crew statements and the evident aircraft realignment was not considered by the Investigation but subsequent minor modifications to related operator runway line-up procedure were noted.

After takeoff, the crew were  presented with a fuel imbalance indication. The imbalance slowly increased until, once level at FL340, a further annunciation indicated that the maximum permitted imbalance had been reached. Actioning the corresponding checklist did not resolve the problem so procedurally recommended shutdown of the low fuel side engine was performed followed by a MAYDAY diversion to Los Angeles. The imbalance was attributed to inadvertent crew selection of ‘gravity crossflow’ prior to takeoff instead of the immediately adjacent ‘crossflow auto override’.