LEDs in runway lights
 

Evening All.

An ex-LL L/Op asks if there has been any experimentation in using LEDs in Rwy and Apc lighting.

I can't see any immediate show-stoppers, but I've been out of it for 11 years now.

TIA

Just Google LED runway lights. There is a lot there.

Judgeing the blueish shine taxiway lights sport on some airports these days, they must be of LED type.

Installed at quite a few airports. Beneficial in terms of acquiring the specified visual reference, but there are still questions about what happens as operators update their fleets and purchase IR-based Enhanced Vision Systems to bring their RVR minima down on CAT 1 ILS systems.

Although low energy I can't help feeling current LEDs are not a panacea:

-pilots often complain about the brightness even when at the lowest settings
-some airport LEDs seem to have a strobe effect which is a bit distracting
-I'm not sure if there is any research in to this, but I think they ruin your night-vision a bit too - there are LED traffic lights on my commute and although they don't appear much brighter than the incandescent predecessors I just can't see anything on the road beyond them and it takes a few metres past them before I can see properly again

maybe it's just me

Exactly the reason my airport decided not to convert to LED when they first became available but I’m guessing things have moved on a bit now, it may be time for us to revisit the option of LED.

I'm assuming each light is a cluster of LED's. Why not include some IR LED's too?

I think this solution has been mooted by some AGL manufacturers. If implemented, it might overcome the issue. Airports examining the potential of this will have to explore the take-up of EVS operations by their customers...this seems to depend on where the operators are in their equipment cycle, i.e. retrofitting EVS to the current fleet is probably too expensive an option, but building it in on the production line would make sense. For future proofing, incorporating LED lights with an IR element would offer reduced running costs, greater light longevity, and EVS capability.

So does that mean some systems presently classed as LI would become HI if retrofitted with LED lighting?
I'm thinking of the many small GA airfields which presently have LI lights which are OK at night but crap in poor daytime vis.

Leeds Bradford is about halfway through a three -winter project to replace the current (incandescent?) installations with LEDs. I don't know if this includes the taxiways as well. It would be nice to have some greens all along taxiway Alpha!

I actually flight test lighting systems in Australia.
Part of the reason they are sometimes too bright is that the electricians leave the transformers at 6.6amps which was required for incandescent type globes. Having now flight tested a good number of LED lit runways we seem to have the settings about right.
What I particularly notice is the clarity of the lights when doing a circling approach at say 4nm. They are far superior to the old incandescent and halogens.

. I think you would definitely notice a difference using LEDs even in the daytime especially during overcast or reduced horizontal viz situations

Actually on the rwy edge, taxiway and THRS lights they are all single LEDs. Although the red/green threshold units are have an LED facing each direction

With new LED road traffic lights, one glaring weakness is that their very lack of heat tends to encourage snow and ice build-up in cold climates.