Attitude Adjustment: Enhanced ATTI Mode for Remote Pilots.

Unmanned aircraft systems (UAS) are a rapidly emerging sector of aviation, however loss of control in-flight (LOC-I) is the largest reported category by the Air Accident Investigations Branch (2021). When UAS unexpectedly revert from global positioning system (GPS) to attitude mode (ATTI), automatic safety features may degrade. This creates a pre-condition for LOC-I. Under visual line of sight (VLOS), remote pilots (RPs) must maintain a constant aircraft watch, but current user interfaces may not offer appropriate alerting for visual tasks. A repeated measures experiment compared RP reaction times against two different ATTI alerts: verbal and passive. Participants with General VLOS Certificates were recruited to fly a maneuver sequence in June 2022 (n = 5). Quantitative data was supported by a qualitative questionnaire. Four research questions (RQs) were asked. RQ1: Is there a significant difference in RP reaction times to unexpected modechanges between a passive system and a verbal ATTI warning system? RQ2: Is reaction time to reversion significantly affected by maneuver? RQ3: Do RPs have a preference of warning system? RQ4: What suggestions do RPs have for warning system design? Results indicate a significant improvement using a verbal system ( p = 0.048), with a large effect ( ƞ p 2 = 0.66). Participants unanimously agreed that verbal alerts enhanced awareness of unexpected reversion. A combined haptic/verbal system was suggested by participants. The theoretical concept “ Alert System Assessment Tool” has been introduced, alongside other RP human factors research areas. This study expands limited research within VLOS alerts and is believed to be primary research into verbal ATTI warnings.