What's this mean?
 

Listening to Heathrow Tower last night, I heard this phrase several times and wondered what it meant. The runway was 27L.

"Callsign 123, turn next right on the greens - hold short at Delta"

Just the bit in bold I'm not sure about!:)

Greens - runway lead-off lights to the taxiway

Thanks! :)

The green taxiway centreline lights are switched to show the route each aircraft is to take. This makes Heathrow one of the best large airports for ground movements from the cockpit point of view.

Ahh... the reds and greens! The whole taxiway system is broken down into segments, at the beginning of each of which there is a line of red lights across the taxiway. When an aircraft lands a green taxiway route is illuminated from the runway to the parking gate. If it is necessary to hold an aircraft a red stop bar can be illuminated, similar to traffic lights. Similarly, departing aircraft are routed to the holding point where a red bar prevents entry to the runway until a green turn-on curve is illuminated by the Air controller.

When they work properly they are God's gift to pilots and ATCOs. When they don't work well they can be a slight nightmare!!!

One Arthur Ruffell was involved with the installation of the reds and greens and when the ATC facilities moved from the move from the north side to the central area the lighting panel was housed temporarily in a building beside the tower affectionately known as "Ruffell's Palace".

Ahh.. that explains what "Ground.. we've got reds on Juliet" was all about one morning at Gatwick!

Fascinating stuff Mr Director, thanks very much!

they look good too when im driving over the crossings in a BA cargo tug....
:)

It's a pity more large airfields don't have the same system. Sometimes the hardest part of the job can be navigating your way around an unfamiliar field, especially at night or in poor visibility.
Vacating the runway after landing and being given a complicated taxi instruction involving several taxiways can result in a flurry of taxiway charts and much head scratching. The controller knows where he wants you to go; it's his airfield and he's very familiar with it. So are the local pilots. But to the stranger, it can be confusing.:confused:

Heathrow at night....."Follow the greens for....." Just brilliant. Takes all the hassle out of life.:ok:

And it's been in use for donkey's years.

Yes I love the term "follow the greens" - makes me feel safer when I have a ICAO level 4 scraper under training.

But, it does remind me of a wonderful incident many moons ago in my ground ops days( HD may remember )
One very very foggy morning, nothing arriving - nothing departing. Aviance were asked to tow the Brymon Dash7 from the bravos to the deltas..... yes the tug driver was told to follow the greens to stand delta xyz..... sometime later, we in ops wondered where he had gone, it was only a few minutes from the bravos to the deltas, so we switched a tug radio to listen out where he was............ and.........
"speedbird xyz, line up and hold 09R at block 89" - reply - "we can't until the dash 7 moves first" - reply - "what dash 7" - reply - "the one in front of us under tow"....... silence....... hasty dispatch of BAA Ops vehicle to find poor lost Dash 7 and bring him back through the departure queue...
Yes the poor hapless tug-driver had dilligently "followed the greens" right to the holding point 09R at block 89 ( old numbers were the best )

Well I did suggest, earlier, that when they didn't work properly life could get exciting!!!! There is actually a thread somewhere on Pprune with a BA(?) pilot saying he didn't like the reds and greens!!!

There was a DC-8 which crashed on take-off from 28R and ended up in a cabbage patch. Immediately word went round that he'd been told to follow the greens. (True).

From an ATC point of view, reds and greens are great however there is an issue with not stopping at a clearance limit. For example if I instuct an aircraft to hold short of Delta (the normal handover point between 2 ground frequencies) but the green route is illuminated beyond Delta, it is not uncommon for an aircraft to keep trundling along into someone elses ground space. Take an airport like Manchester who have all greens illuminated, it makes the crew concentrate a little more on where they have to route/stop. Switchable reds and greens can make people a little lazy :)

<<if I instuct an aircraft to hold short of Delta (the normal handover point between 2 ground frequencies) but the green route is illuminated beyond Delta, >>

Do you not have a red stop bar there??

HD - you forgot to mention the teamwork bit.
The lighting panel controlling these lights is operated not by the GMC controller but by an assistant who monitors the GMC contoller's instructions to the pilot and sets up the route as necessary. When you have say 20 different aircraft all using different routes, you have to have absolute trust in each other!!

Chev.. Dead right, T. I owe my life to some of the lighting ops. I still cannot fathom how they did it - witchcraft and black magic involved somewhere!

The majority of the time the receiving lighting panel operator (LPO) will continue a route past the clearance limit if it is safe to do so. This may be set up before the controller has actually transferred the aircraft to the next controller. So, a red bar may not always be illuminated at the handover point and hence occassionally leads to aircraft overshooting their clearance limit :=

A typical controller could have up to 20 aircraft on frequency at any one time - outbounds, inbounds and tugs. Each will have a clearance limit. It is pretty much impossible for the LPO to bring up the red bar after every single aircraft at the handover points/clearance limits.

Anyway, it works 99% of the time :ok:

Have to take issue with you here, point5.
It's not about people being a little lazy. It's about CRM and safety.

The system at LHR allows both pilots to look out of the window and watch where they're going and not have to keep looking inside to refer to a taxiway plate.

The MAN lay-out of taxiways is not user friendly and should certainly not be held up as an example of how an airfield should be designed.

I supose you'll be suggesting next that autopilots should not be used as they make people lazy......keep those pilots busy, don't let them slack.... Ah, it's not like it was when I was a lad, serving my time before the mast on DC3s......Didn't know what an autopilot was...Flight director?....Pah! Whoops, didn't see that mountain there! Was too busy looking at the plates. :rolleyes:

The last bit, by the way, is gentle sarcasm in case there's any doubt.

Red and Green and Yellow and Blue.....
 

....and what younger PPRuNers won't remember is that Heathrow - then known simply as "London Airport" - also used to have a similar system for pax! In its first "proper" passenger terminal, then known as Europa and even now still forming the core of Terminal 2, there was a system of ceiling lights - about 4 or 5 colours I think - that illuminated along the route from departure lounge to the gate. Flight announcements went along the lines of:"Flight BE123 to Paris is now ready for departure. Passengers for this flight should follow the blue lights to the boarding gate".

It was simple and AFAIK it worked perfectly until the number of flights boarding around the same time overtook the number of colours available!

Seloco - yes the Lighting Op was REALLY busy in those days!!