External lighting use in Fog
Thread Starter
External lighting use in Fog
Just curious on other people's thoughts regarding the use of aircraft external lighting (landing lights, taxi light, nose take-off light) during low visibility operations (autoland in fog), day and night.
Some check and training pilots teach "lights off (night only)" but I can't find this in the official published aircraft manufacturer SOP (anticipating the reply - "just follow SOP").
Some check and training pilots teach "lights off (night only)" but I can't find this in the official published aircraft manufacturer SOP (anticipating the reply - "just follow SOP").
No SOP where I am but I turn the lights on, and based on whether the view outside looks better or worse, either leave them on or turn them off again. I would be wary of ground operations in LVPs with no lighting at all, especially if you are not the only movement...
Thread Starter
Yes the autopilot does a great job usually (with or without lights), but for certain approaches (eg CAT 2) we must "sight" some runway lights otherwise it is a go-around.
It's not as simple as selecting the lights ON or OFF at minima to determine if I can see better.
It's not as simple as selecting the lights ON or OFF at minima to determine if I can see better.
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I'm not being flippant, but just do what works best for you based on what you can or cannot see. This or that trainers "advice" is just that. They aren't there when you are out on the line doing it for real. The aircraft will complete the autoland even if both drivers are sat in row 7 whether the lights are on or off.
For me, B737 I use the RWY TURN OFF lights only for LVO. It provides some external lighting to allow the airplane to be seen, without creating a light screen in front of the airplane that the LANDING lights do.
No lights on at all certainly provides the best view at night in low vis however.
cheers
No lights on at all certainly provides the best view at night in low vis however.
cheers
For an approach, landing and departure once on the active our company recommends lights off to maximise external visual cues. Being seen isn’t a priority on a protected runway. Once at taxi speed do what’s works best but you have to balance the need to be seen with the need to see.
Twice in my career I’ve had to stop and set the park brake as we couldn’t see anything during taxi, once at Delhi the other at Seattle. Both times we lit the the plane up like a Christmas tree in the hope that the others still moving would see us.
Twice in my career I’ve had to stop and set the park brake as we couldn’t see anything during taxi, once at Delhi the other at Seattle. Both times we lit the the plane up like a Christmas tree in the hope that the others still moving would see us.
Landing Lights Off
A report on the research flying by RAE Bedford (BLEU) - TR 81025 - ‘Economic Cat 3’, suggests that landing lights were not used for any approach. However this was probably due to assessments of different approach and runway lighting configurations and intensity - landing lights off to minimise scientific variability.
The most usable intensities for the runway were a graded change from ‘low’ centreline, ‘medium’ TDZ, and ‘higher’ edge lights; generally both the runway and approach lights set to lower intensities than might be considered.
The report did discuss a small trial involving use of landing lights (possibly without or only with very low intensity runway lights, also with floodlights without runway lights). There were few benefits from these other than at very low altitude when the landing lights enhanced ground texture - for manual landings.
Generally the suggestions were that the reflected dazzle of landing lights was less disturbing than having incorrect, too bright approach and runway lights.
Personal recollection was that landing light dazzle on the approach reduced the height of first contact with the approach lights; and during landing in variable thickness fogs the changing light intensities from the reflections could disturb awareness of the runway lighting pattern. Thus use of landing lights at night could reduce time available for assessing the visual scene - critical decision making, and any benefit during the flare would only apply to pure unaided visual landings (none authorised ?), with potential for distraction in variable fog - blowing snow, etc.
The manufacturer is unlikely to advise - operational issue / approval; thus it depends on the operator or regulator. Requirements vary considerably; those who have considered the research and feedback from other operators, and those who intuitively - erroneously require max approach / runway brightness, and landing lights without considering any negative effects.
Landing lights off.
The most usable intensities for the runway were a graded change from ‘low’ centreline, ‘medium’ TDZ, and ‘higher’ edge lights; generally both the runway and approach lights set to lower intensities than might be considered.
The report did discuss a small trial involving use of landing lights (possibly without or only with very low intensity runway lights, also with floodlights without runway lights). There were few benefits from these other than at very low altitude when the landing lights enhanced ground texture - for manual landings.
Generally the suggestions were that the reflected dazzle of landing lights was less disturbing than having incorrect, too bright approach and runway lights.
Personal recollection was that landing light dazzle on the approach reduced the height of first contact with the approach lights; and during landing in variable thickness fogs the changing light intensities from the reflections could disturb awareness of the runway lighting pattern. Thus use of landing lights at night could reduce time available for assessing the visual scene - critical decision making, and any benefit during the flare would only apply to pure unaided visual landings (none authorised ?), with potential for distraction in variable fog - blowing snow, etc.
The manufacturer is unlikely to advise - operational issue / approval; thus it depends on the operator or regulator. Requirements vary considerably; those who have considered the research and feedback from other operators, and those who intuitively - erroneously require max approach / runway brightness, and landing lights without considering any negative effects.
Landing lights off.
I’m with Jim Hacker (⌗2) on this. Common sense again.
Landing and Taxi light backglare, flashing Nav lights, rotating beacons all distract.
Maybe, if you need to be seen, then keep the steady ones on.
Landing and Taxi light backglare, flashing Nav lights, rotating beacons all distract.
Maybe, if you need to be seen, then keep the steady ones on.
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We can only do Cat 2 approach and our SOP states to turn off all lights except Nav Logo. You can try in the sim, if you keep all the lights ON as per normal, it’s more difficult to see the runway lights.
Water droplets reflect/refract light to its point of origin; like reflective hi-viz material. That's why car manufacturers mount forward fog-lights low down, away from the driver's line of sight. You may find that wing-mounted landing/taxi lights give less glare than fuselage mounted ones.
