How linear visual aids restore nighttime depth perception
At night, everyone loses their depth perception, so from a distance,
with point source visual aid lights, one cannot tell which light is beside or in front of another.
therefore, point source visual aids, provide a minimum of flight information to pilots flying towards them.
Linear visual aids restore pilots' nighttime depth perception. from a distance, they provide lit angles which the brain interprets and then provides dimension to the helipad.
Depth perception and dimension, allow pilots to gauge KEY VECTORS like;
distance;
closing speed;
height;
ANGLE OF APPROACH;
landing Height above the ground
and other key vectors,
all are important for improving nighttime helipad safety.
to illustrate; BELOW ARE IDENTICAL PHOTOGRAPHS. ALL THAT HAS CHANGED IS THAT THEY HAVE BEEN DARKENED TO MAKE THE HELIPADS MORE DIFFICULT TO SEE. representing helipads at night are darkened photos that illustrate how everyone loses their depth perception at night.
NOTE: what is Important for good visibility, is having a good contrast between what one is trying to see and its background.
As the pictures below and these colored letters try to illustrate when one loses contrast AND DEPTH PERCEPTION, everything becomes more difficult to see OR UNDERSTAND, especially from a distance.
Below are Identical Pictures, But The Left One Has Been Darkened.
The picture below is taken standing next to a fully compliant FAA / ICAO helipad, with all its point source lights lit.
Despite standing right next to the helipad, it is difficult to make out the lit helipad landing pattern.
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Fully Compliant FAA / ICAO Helipad Lighting;
which is difficult to see or understand even when the picture is taken right next to the helipad!
The Same Fully Compliant FAA / ICAO Helipad Lighting with more ambient light. The point source lights are still somewhat confusing, however, their pattern can be more easily made out because of the concrete pad and its painted markings.
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With more ambient light on the subject and BETTER CONTRAST, it is easier to see the light pattern and tell what they mean. Especially when the concrete pad and its painted markings are also visible. However, even here, with much more ambient light and standing right next to the helipad, the point sources are still somewhat confusing. This confusion disappears with linear sources.
Below are pictures of a joint FAA and Port Authority of New York and New JerseyPANYNJ Helipad Linear Visual Aid Research; January 1999, from the video of The Downtown Manhattan Helipad, made by (PANYNJ).
This research was detailed and published by the FAA at The FAA Heliport Vertiport Lighting Conference Proceedings,
Nov 1999 (DOT/FAA/ ND 99/1) .
Note: The helipad below meets all FAA regulations, yet, at night, standing close to the helipad, the pattern of lights is very confusing. For pilots from a distance, these point source visual aids would be even more confusing and their pattern even more difficult to make out, particularly if they were approaching the helipad at low angles.
At Night Everyone Loses Their Depth Perception, So, Unless One Is Above Or Looking Along Them, With Point Sources, One Can Not Tell Which Light Is Next To, Behind, Or In Front Of Another. At Night, This Causes Confusion!
Below is the PANYNJ helipad, with point sources.
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The same picture with both point sources and linear visual aids.
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The same picture now without the point sources having just the linear visual aids.
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Even though all the pictures remain very dark, this early extruded linear LEDline®, although much less bright than today's linear LEDline®clearly demonstrates that: • Because of the linearity, linear visual aids provide for immediate recognition of the helipad’s area/dimension. There is no
doubt, hesitation, or confusion once there are no point source points of light compared to viewing linear visual aids at
night. • Therefore, since there is no confusion, linear visual aids provide a better nighttime definition of any helipad, even when
viewed at shallow angles, they still provide viewers with dimension.
As further evidence; below are a series of blue point source lights from the same helipad, which, when viewed from a distance, are difficult to see exactly what they represent. Indeed, it is clear that these blue point source lamps, provide NO depth perception for viewers.
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Again, here is the same picture, but with more ambient light. The blue lights are standard taxiway edge lights running at step 5 the brightest they can go. Despite this, the linear lights are still better! Both of these pictures were taken from the enclosed video.
Video: PANYNJ and FAA Linear Visual Aids Research, at the Downtown Manhattan Helipad
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At Night, With Linear Sources, Because Their Aspect Ratio Changes With Any Angle One Looks At Them, One Always Understands Which Light Is Beside Or In Front Of Another. In Effect, At Night, Their Linearity Effectively Restores One’s Lost Nighttime Depth Perception.
LEDline® safety and guidance at the Golden jubilee Hospital, 2012 Clydebank Glasgow, UK
The picture below is by Peter Simpson of
PSNK Aeronautical Services
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Video of LEDline® safety guidance lighting at the Golden Jubilee Hospital Helipad, Glasgow, Clydebank, UK
LEDline® safety and guidance lighting at a USA helipad, used for both private and hospital access.
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USA helipad Copyright Bruce Lomesky
LEDline® Safety and Guidance Lighting at Kilmore Hospital Helipad, Australia:
Copyright Peter Simpson PSNK Aeronautical Services
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LEDline® Safety Guidance lighting at the Leongatha Hospital Helipad, Australia.
Copyright Peter Simpson PSNK Aeronautical Services
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