H2F BITESIZE #8

I bring you a weekly bite-sized chunk of the science behind helicopter human factors and CRM in practice, simplifying the complex and distilling a helicopter related study into a summary of less than 500 words.

TITLE:

Helicopter pilot performance and workload in a following task in a degraded visual environment.

WHAT?

A simulator study comparing pilot performance in the task of following a go-fast vessel in a good vs degraded visual environment (GVE vs DVE).

WHEN?

Published 2023.

WHERE?

TNO Netherlands, on a sample of 16 Dutch military pilots.

WHY?

Degraded Visual Environments (DVE) are associated with increased risk of spatial disorientation. This study investigated the negative impact of DVE on performance and whether helmet mounted display (HMD) symbology could mitigate it.

HOW?

Pilot performance was measured against a manually-flown task of following a go fast vessel in GVE and DVE, with and without HMD. The target vessel was manoeuvring with speed and heading changes. Objective performance measures included control input, gaze direction, and position keeping. Subjective measures were pilot self-ratings on performance, SA, and workload.

FINDINGS:

• In DVE pilots perceived higher workload, flew closer to the go-fast vessel, and responded with larger control inputs to vessel manoeuvres.
• Pilots rated their performance and task execution significantly lower in DVE and their effort rating higher.
• HMD did not improve task performance but did lead to increased pilot gaze time outside the cockpit, leading to improved SA and workload.
• In GVE pilots allocated 59% of attention outside, 35% to HMD and 6% to cockpit instruments whereas in DVE 43% was outside, 49% (most of their attention) was on the HMD, and 8% scanned the instruments.

SO WHAT?

• DVE negatively impacted pilot task performance and did so even with HMD symbology.
• Pilots compensated for degraded visual cues by flying closer to the go-fast vessel to maintain adequate references, but this reduced the margin to anticipate its manoeuvring and thereby provoked greater control inputs.
• Nevertheless, HMD for dynamic low altitude flying tasks could help to improve SA and lower workload irrespective of visual conditions.

REFERENCE: 

Ledegang, W.D. van de Burg, E., Valk, P.J.L., Houben, M.M.J., Groen, E.L. (2024). Helicopter pilot performance and workload in a following task in a degraded visual environment. Aerospace Medicine and Human Performance, Vol.95, No.1, DOI: https://doi.org/10.3357/AMHP.6266.2924