Unusual Attitude Recovery Using the Roll Arrow

As part of the NASA High Speed Research program, an unusual attitude (UA), pilot-in-the-loop simulation study provided information on Primary Flight Display (PFD) symbology factors that affect UA recovery. Overall research objectives were to evaluate symbology concepts to facilitate pilot perception and safe recovery.

It was concluded that UA recognition and recovery task performance is unacceptable when the pilot relies only on raw data but is improved markedly with appropriate second-generation symbology. The major result indicated that a newly-developed PFD symbol (the Roll Arrow) significantly reduced UA recognition errors. The Roll Arrow is a large, red arrow attached to the PFD Bank Angle Pointer. When the aircraft is in a UA, the Roll Arrow appears on the PFD and points left or right to indicate the required direction to roll for recovery. Other recovery actions are at pilot discretion.

In comparison to other evaluated symbology designs, the Roll Arrow was associated with 90% reduction in pilot error. Workload, situation awareness, and pilot opinion all favored the Roll Arrow.