Pilots' Gaze Behavior During Simulated Helicopter Air-to-Air Refueling

Refueling mid air is considered as important force multiplier for e.g. conducting search and rescue operations. Due to close proximity to the tanker, the refueling hose and drogue as well as the receiver can be strongly affected by the tanker's wake. Thus, the refueling drogue extended from the tanker by a hose is often oscillating from turbulence. Contact with the tanker has to be established by positioning the receiver's refueling probe within the tanker's drogue. During qualification training pilots are instructed to not focus on the drogue, due to its oscillations. This is done since chasing the drogue often leads to over-controlling and therefore mostly to a failed contact attempt. The presented research aims for improving today's Helicopter Air-to-Air Refueling (HAAR) as well as related training efficiency by a gain of understanding in this phenomenon. Therefore, the HAAR real-time simulation scenario at German Aerospace Center's (DLR) Air Vehicle Simulator (AVES) was extended with a multi body hose and a probe/drogue contact model to enable realistic contact initiation. During a piloted campaign, a total of six pilots with different levels of HAAR experience conducted the maneuver. This paper presents an analysis of obtained eye tracking data with regards to gaze entropy, total fixation duration on defined areas of interest and corresponding time history of control inputs. Potential links between gaze entropy and perceived workload that might be observed in the data are also discussed. Results show that the metrics can highlight differences in successful and unsuccessful attempts for contact of HAAR experienced and inexperienced pilots.