TWY center lights

[Becker Junior]

Hi folks. I heard that there is a standard regarding the taxiway center lights and the yellow line. The line should be always at the same side of the airport terminal. Example: taxi yellow line slightly left of the center lights should mean the airport is at your left. Is it true? I searched but didnt find anything about it.
Thanks,

[Spitoon]

Never heard of this myself - and many airports will have bits of airport infrastructure on both sides of the taxiway.

It used to be the norm for the painted centreline and lights to be aligned (i.e. both centred on the same route)...until someone spotted that off-setting the line by a few centimetres would make it much easier to re-paint the line and help to avoid getting paint all over the light pots. I don't think I've seen a line that isn't off-set for years.

[fireflybob]

This is an interesting point. I noticed that at Dublin the new taxi centreline yellow markings are slightly offset from the lights but feel sure that they are on the same line at other airports. Something to look for next time!

I had conjectured that this was so that the nosewheel isn't banging on the centreline lights when one was aligned on the yellow line.

As an aside, do you think it matters if the nosewheel runs over the centreline lights during the take off run or not?

[Leave 5 on the glide]

I can't say that I've heard of that one. In the US the RWY centreline lights are offset a maximum of 2 feet to the opposite side of the centreline from the major runway turnoffs.

I hope that's of some use .....

l5otg

[point8six]

Interesting - many airports lack even lights at the edge of the taxiway. Is the yellow line meant to be seen at night in heavy rain? Lighting and signage at major airports are deplorable - the sooner "Safe-route" or equivalent becomes mandatory, the sooner taxiway and runway incursions will decline in number.

[fireflybob]

Is the yellow line meant to be seen at night in heavy rain?

There are yellow lines at certain airports which are barely visible to my eyes by day!!

[mnttech]

In the US, airport lighting is controlled by AC No.: 150/5340-30C , Design and Installation Details for Airport Visual Aids


Runway Centerline Lighting.

(1) Location. The runway centerline lights are located along the runway centerline at 50 foot (15 m) longitudinal intervals per Figure 33. The line of runway centerline lights may be uniformly offset laterally to the same side of the physical runway centerline a maximum of 2.5 feet (0.8 m) measured from the physical runway centerline to the fixture centerline.

Taxiway Centerline Lighting
Longitudinal and Lateral Spacing. ... Displace centerline lights laterally a maximum of 2 feet (0.6 m) (to the nearest edge of the fixture) to avoid rigid pavement joints and to ease painting the centerline marking.


But, we have seen where some airports don't always do it this way, and there is some text in the AC about if this is for a new runway or not. We have had to call different airports to find out where they lights are at, just to get our visual models correct for some of the NSP staff. IMO, wasting lots of time (read $$$) for something that most pilots could not tell you.

[Bedder believeit]

Point8six. The normal requirement is green centreline lighting down the centreline of the taxyway, and blue lights on the edges only at corners/turnouts. You only need side taxyway lighting if the taxyway is part of a defined CAT III taxy route.

[point8six]

Yes - the emphasis is on "normal"!

[Throttle Arms]

I'm not familiar with the US regulations, Annex 14 and most ICAO signatory countries will permit an offset of 60cm on a runway (Annex 14, 5.3.12.5)and recommend no more than 30cm on a taxiway Annex 14, 5.3.16.11).

Ideally they should not be offset but it happens as taxiways/runways are widened or resurfaced (usually a cost savings measure, haven't heard of it being done on purpose for ease of painting, although it is one benefit).

bedder believeit, Can you point me to the relevant standard for requirement of blue lights at corners/intersections? As far as I know, blue edge lights are not required on taxiways equipped with centre line lighting (Annex 14, 5.3.17.1).

[Tinstaafl]

Continuing with taxiway lighting: In the US I don't think I've *ever* seen green centreline lights except for runway lead off lights. Small aerodromes, large airports makes no difference - they're enamoured with blue sideline lights here. One would think green centreline lights are anathema.

It's a pain ! One is confronted with a carpet of 'blue light - black space - blue light - black space -blue light - black space...' so spotting the line of a taxiway amongst the sea of blue/black/blue/black/... is so much more difficult than spotting strings of green. It's just not as easy to determine 'I can taxi into that black area but not into that similar size black area next to it'. Especially at an unfamiliar airport. In the darkness of night one black area looks much like another black area so having a group of taxiways marked by blue edge lighting - but nothing that distinguishes the dark taxiway from the dark non-taxiway - just makes it more difficicult than it needs to be. Even worse is when taxiways are of a width that is similar to the spacing between the taxiways.

I believe that *all* taxiways should be required to use green centreline lighting with blue sideline lights reserved for corners and ramp/apron boundaries where the expectation is that you can taxi anywhere between the easily determined blue boundary.