Why is there a section of low roadlights on the m40 alongside heathrow airport?

Question

I have heard it is something to do with planes not mistaking the road for a runway but I need details to prove this is the case as the opposing argument is s the lights are lower than normal they are more likely to look like runway lights.

Answer 1

Airport runways are surrounded by a number of safety zones. One of these is the "lateral slope." This begins at the runway edge and procedes at a slope of 2 degrees parallel to the runway centerline for 5 miles. Any item that pierces that lateral slope (building, lamppost, etc.) requires a waiver from the national aeronautical authority -- the FAA in the US and the CAB (I think) in the UK. If the waiver is denied, the obstruction must come down. Hence the low-mounted roadlights on the M40 and other areas around Heathrow and other airports.

Answer 2

As Michael S says. you are probably thinking of Northolt on the A40. The lights are lower there because the runway starts just the other side of the perimeter fence and landing craft need to come in low. If you came off the A40 and took the Ruilip road you would find that where the other end of the runway meets the road there are "traffic lights" which stop vehicles from passing whilst there are takeoffs and landings.

There might also be half height lights on the A30 at the southern side of Heathrow. To the north of Heathrow there is no need for lower lights as there are buildings between the runways and the A4. The same goes for the M25 to the west terminal 5 now stands between the runway and motorway and also there was sufficient distance between the road and runway not to need lower lights.

Answer 3

If anything the lights are low so the planes don't damage them during landing.
Runways / airports use colored lighting representing different aspects of airport operation. These lights are bright and designed so landing aircraft see them CLEARLY, but yet they don't blind any type of traffic nearby.

I don't see how any pilot could possible confuse a highway for a runway.
Next time you are on a plane that will land during darkness sit at a window seat. Look at the highways, they look yellowish. As you approach the airport look at the BRIGHT blue, red, green, white and yellow lights.
I have always enjoyed coming in to land at night. The lighting is really beautiful.

Answer 4

There is a restriction on the height of objects in the flightpath near runways, hence the lower road lighting.
The way the lights on a runway are arranged means it would have to be a very stupid pilot to mistake it for a motorway.

Answer 5

Heathrow is nowhere near the M40.
You may be thinking of RAF Northolt, which has a long section of half height lights.
May be because the smaller aircraft that land there come in at a lower angle/height?

Answer 6

At airports the have things called flight paths if u or an item, i.e. buildings, are in that flight path there are restrictions on how high that object can be. So basically its just a safety factor that the lights are lower in that 1 spot.

Answer 7

I'd say it's a safety issue, those planes fly pretty low over the m40

Answer 8

Try askin Heathrow, but I am sure that it's right.

Answer 9

Yes its true darling/.

Answer 10

SOME PADDY DUG THE HOLES TOO DEEP !!!!!!