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 flight with night vision goggles – human factors aspects
WHAT?
For those wanting a ‘deep dive’ into the human factors of night vision systems, this comprehensive introduction, albeit slightly dated, is a great place to start, covering all the fundamentals..
WHEN?
1989..
WHERE?
USA, NASA AMES Research Centre.
HOW?
This paper reviews night vision and night vision systems and summarises all the main human factors and limitations they bring.
WHY?
Even experienced users of night vision goggles who will recognise many of the limitations of both the devices and human vision discussed here will find new insights amongst the detail of this paper. One of these, discussed below is the natural physiological differences between individual pilots’ susceptibility to problems associated with NVG usage.
EXTRACTS:
Night acuity:
- Individual vision standards differ for day or night vision. A pilot with perfect eyesight in the daytime can have deficient device-aided night vision, and probably does not know it. Military and civil regulations set standards for visual acuity, but there are no standards for night vision set in regulation, or tested. A significant proportion of people suffer from night myopia.
- Night-vision capability is much more difficult to define and measure than day vision because it is highly dependent on factors such as level of dark adaptation, illumination levels, and the presence of dazzling light sources. Some pilots are not aware that their night-vision is deficient, or choose to ignore it.
- A second condition called instrument myopia requires optical correction when viewing through optical instruments. Although it is possible to compensate this with NVD settings, many pilots are not aware of their limited night-vision or instrument-vision capabilities and do not know whether the image they are watching is optimal.
INDIVIDUAL DIFFERENCES:
- This physiological suitability for NVG flight is most clearly manifested in differences between the level of fatigue experienced. Many report higher than normal visual fatigue or general fatigue during or after as little as an hour of NVG flight, while others feel that it doesn’t differ from flight without goggles on a bright night.
- In a laboratory setting large individual differences have been observed among experienced NVG pilots in visual acuity and contrast sensitivity, but only a small number of pilots are aware of their naturally limited abilities with NVGs. Many pilots experience visual fatigue after relatively short periods of flight leading some to resent the requirement to use them.
REFERENCE:
Brickner, M. S. (1989). Helicopter flights with night-vision goggles: Human factors aspects (No. NASA-TM-101039).
competentaviators.com 