Runway/Approach LED lighting
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Runway/Approach LED lighting
Does anyone else harbour a high intensity dislike of LED approach, touchdown zone and runway lighting?
I find, and have heard similarly from colleagues, that depth perception is significantly more difficult when faced with an array of very intense pin-point white lighting. A white runway LED, for example, 1000m away appears to me to be exactly the same intensity one 100m away.
I find, and have heard similarly from colleagues, that depth perception is significantly more difficult when faced with an array of very intense pin-point white lighting. A white runway LED, for example, 1000m away appears to me to be exactly the same intensity one 100m away.
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Pontious,
I only have one experience and that was of Baku. It was horrible. I presume the depth perception is degraded because the lights are so intense and piercing. I also noticed some kind of discoloration effect, especially the final 900 meter segment as the white and red alternating lights seem to merge and became more a curiosity rather than being immediately recognizable.
They should be regarded as a briefable threat!
I only have one experience and that was of Baku. It was horrible. I presume the depth perception is degraded because the lights are so intense and piercing. I also noticed some kind of discoloration effect, especially the final 900 meter segment as the white and red alternating lights seem to merge and became more a curiosity rather than being immediately recognizable.
They should be regarded as a briefable threat!
Last edited by Kefuddle; 30th May 2013 at 20:32.
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If the fixtures do not diffuse the light from the extremely bright LED into a beam over several cm, then I would expect you to potentially get problems with perception. As a 5mm pupil is good for seeing a resolution of about 1cm at 100m. If you present several bright points a few cm apart that might start to look odd. I suspect the biggest thing is just relatively glaring brightness compared with old style lighting.
At night, I find LED road traffic lights odd to look at once within about 5-10m, and they have a few mm separation between the LEDs.
At night, I find LED road traffic lights odd to look at once within about 5-10m, and they have a few mm separation between the LEDs.
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I do appreciate your concern when it comes to depth perception, however those lights have saved me several times, now. And in marginal wx, I would rather see the lights at minimums and thereafter struggle a little bit, than go around and divert. They really do help. As for depth perception, once you get into the flare phase you have made it, haven't you?
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Is the high intensity a bug or a feature? Can't the makers modulate the intensity down a bit?
They do come with a couple of settings, AFAIK. Is this the ATC going overboard with the knobs?
They do come with a couple of settings, AFAIK. Is this the ATC going overboard with the knobs?
I found the LED's at LGW to be very good and clear.
A tad bright perhaps, but we only have to ask for them to be turned down.
A tad bright perhaps, but we only have to ask for them to be turned down.
Having said that, there is a sort of 'LASER' quality to high intensity LED lights, which does make it harder to estimate the distance to them.
I noticed this last night as we taxied in - the blue taxy edge lights are LEDs where I am based. I was looking at a series of these lights located at increasing distances from the cockpit, but they all seemed to be on the same 'plane' as it were, i.e. all at the same distance from us, even though obviously they weren't.
I noticed this last night as we taxied in - the blue taxy edge lights are LEDs where I am based. I was looking at a series of these lights located at increasing distances from the cockpit, but they all seemed to be on the same 'plane' as it were, i.e. all at the same distance from us, even though obviously they weren't.
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I find the standard settings way too bright and as reported here find the dazzling effect a brief able threat. Perhaps even keeping the flight deck lighting up higher than normal for a night landing to mitigate. Once in the flare the touchdown zone is so bright depth perception is gone.
I'm sure in LVPs they may be useful but for normal operations the intensity a standard settings is simply too high.
I'm sure in LVPs they may be useful but for normal operations the intensity a standard settings is simply too high.
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They remind me of a very old PC flight simulator, where each runway light was represented by a single pixel, regardless of the distance from the source.
I can't buy a decent landing on the LED runways...
I can't buy a decent landing on the LED runways...
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I can't buy a decent landing on the LED runways...
I have no objection to LED lighting per se, but to the attitude from a certain Mancunian airport who refuse, point blank, to adjust the level down from "eyeball searing".
Last edited by Fursty Ferret; 27th Aug 2013 at 09:33.
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I filled out the questionnaire that Manchester sent out pre installation of LEDs on 05L/23R expressing my concerns at the glare during night time operations
. I suspect it ended up in the bin. I'm sure the reduced cost of operating and maintaining led lights had nothing to do with the decision to install them
. I suspect it ended up in the bin. I'm sure the reduced cost of operating and maintaining led lights had nothing to do with the decision to install them
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I took a look at what is being done about LED glare. I know that the commercial introduction of LED systems has been delayed due to the glare issue, but only now did I see the reasons and work behind it. The Manchester trials were not in vain it seems.
Take a look at this presentation from "Latest Developments in the Application of White Runway LEDs on Airfields" (2011).
LEDs on Airfields
Please bear in mind that this paper was given in 2011, and things have moved forward from there. In mid-2013, I was told that intense R&D has been ongoing to solve the issues of glare, colour, degradation and temperature (which affects colour and degradation). On the direct issue of perceived brightness, the current advice is that:
- Large variance between test subjects
- Same measured intensity looks brighter in LED due to the Helmholtz-Kohlrausch effect: “As a stimulus becomes more chromatic at constant luminance, it appears brighter”– Described by Kohlrausch in 1947
- Complex steps and functions within eye and brain => Optical illusions
- Source of much research in ICAO and FAA LRC. Both FAA and ICAO have dedicated industry working groups looking at airfield lights and how and what regulations should be put forward.
I suggest that if you are finding problems with lights in operations, then forward those to your Regulator because LED engineering solutions appear to me to be driven by the Regulators' demands. The more they know about problems in the field, the easier it is to ensure that they will be mandated to be addressed. The link given above by TRC's post to the UK document gives the contact for the UK.
Take a look at this presentation from "Latest Developments in the Application of White Runway LEDs on Airfields" (2011).
LEDs on Airfields
Please bear in mind that this paper was given in 2011, and things have moved forward from there. In mid-2013, I was told that intense R&D has been ongoing to solve the issues of glare, colour, degradation and temperature (which affects colour and degradation). On the direct issue of perceived brightness, the current advice is that:
- Large variance between test subjects
- Same measured intensity looks brighter in LED due to the Helmholtz-Kohlrausch effect: “As a stimulus becomes more chromatic at constant luminance, it appears brighter”– Described by Kohlrausch in 1947
- Complex steps and functions within eye and brain => Optical illusions
- Source of much research in ICAO and FAA LRC. Both FAA and ICAO have dedicated industry working groups looking at airfield lights and how and what regulations should be put forward.
I suggest that if you are finding problems with lights in operations, then forward those to your Regulator because LED engineering solutions appear to me to be driven by the Regulators' demands. The more they know about problems in the field, the easier it is to ensure that they will be mandated to be addressed. The link given above by TRC's post to the UK document gives the contact for the UK.
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Already caused incidents
Use of LEDs has already caused at least one incident where a Delta aircraft landed on an LED edge lit parallel taxiway rather than the runway.
See Incident: Delta Airlines B763 at Atlanta on Oct 19th 2009, landed on taxiway
At the time of the incident the runway edge and center line lighting was operated at low intensity (step 1 of 5, equivalent a current of 2.8 amps). Both edge lights of the taxiway M were operated at high intensity (step 5 of 5, equivalent to a current of 6.6 amps) and the taxiway center line lights were operated a medium intensity (step 2 of 5, equivalent to a current of 3.4 amps). The taxiway lighting at the east end of taxiway M had been replaced with LED type lights in 2009 during an upgrade. Pilot comments had been received that the LED type lights appeared much brighter than the other original incandescent lights but no formal pilot input was collected. The FAA determined that pilots do not like intermixing incandescent and LED lights, but did not publish any standard for intermixing the lights.
Flight tests showed that it was challenging to identify the runway lights of runway 27R as the taxiway lights appeared much brighter. Aligned with runway 27L and side stepping with the same light settings as during the incident flight the runway center line lights were not identifyable and the taxiway lights were much more prominent. While on final to 27R the taxiway lights were still more prominent than the runway edge lights. At 500 feet AGL the runway center line lights were barely visible and it appeared several of them were out. The colour of the taxiway lights became distinguishable at about 500 feet AGL.
Flight tests showed that it was challenging to identify the runway lights of runway 27R as the taxiway lights appeared much brighter. Aligned with runway 27L and side stepping with the same light settings as during the incident flight the runway center line lights were not identifyable and the taxiway lights were much more prominent. While on final to 27R the taxiway lights were still more prominent than the runway edge lights. At 500 feet AGL the runway center line lights were barely visible and it appeared several of them were out. The colour of the taxiway lights became distinguishable at about 500 feet AGL.
