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Q: Lights near airports ( Answered 4 out of 5 stars,   1 Comment )
Subject: Lights near airports
Category: Science > Technology
Asked by: blazius-ga
List Price: $5.00
Posted: 29 Jul 2002 12:25 PDT
Expires: 28 Aug 2002 12:25 PDT
Question ID: 46551
I live close to a small airport, serviced by both military and
civilian aircraft.  Within and outside the fenced-off areas there are
quite a lot of elaborate, skyward directed lights that has no other
plausible function than acting as navigation clues for the pilots.  I
think I understand the purpose of the lights that are directly by the
end of the runway.

However, there are some bright, orange-coloured lights that are not
located in obvious locations.  They do not mark dangerous areas (such
as elevated spots or power lines), and they are not lined up with the
centre line of the runway.  Some of them are located in places that
are difficult to reach (in the middle of forests, in mountainous
areas, on islands).  I do not know if the lights add up to some kind
of pattern.  The lights seem to be turned on at all times, even in
bright daylight and when the airport is closed.

What is the purpose of these lights?  Can you point me to any
international standards describing the use of navigational lights on
and near airports?

Request for Question Clarification by huntsman-ga on 29 Jul 2002 16:13 PDT

What country do you live in?

Regarding the orange lights that you are referring to:

1. Generally speaking, how far away are they from the airport?
Kilometers or miles?
2. Do these lights appear to rotate or flash?
3. Is there any type of antenna array or tower in the middle of these
4. Is the color distinctly orange, or could it be similar to the
yellowish-orange color created by sodium-vapor street lights?

There are several types of runway lights, such as flashing white
"REILs" (Runway End Identifier Lights) and sequentially strobing
"APLs" (Approach Lighting Systems), but these are usually positioned
immediately at the end of a runway or within a few hundred yards of



Clarification of Question by blazius-ga on 29 Jul 2002 23:08 PDT
I live in Norway.

1. The lights I have found are a few km from the airport.  I do not
know of any lights more than 10 km away.
2. The lights does not have any kind of rotating/flashing pattern.
3. There are no evident antennas nearby.
4. The colour is similar to that of some streetlights.

Request for Question Clarification by eiffel-ga on 30 Jul 2002 08:39 PDT
In what direction do the lights shine? Straight upwards, horizontally,
or at an angle?

Is there one light at each site, or a cluster?

Clarification of Question by blazius-ga on 30 Jul 2002 11:30 PDT
The lights shine straight upwards, possibly at a small angle. There
seems to be more than one lamp at each point, but they are close to
each other and will probably appear as one point when viewed from a
distance.  I guess one of them acts as a backup for the other.

Request for Question Clarification by huntsman-ga on 30 Jul 2002 17:07 PDT

Thus far, it's hard to say what these lights are. There are radio
marker beacons for Instrument Landing Systems that can be several
kilometers away from an airport, but these would have antenna arrays.
There are also older systems of visual markers that might be some
distance away, but these have largely been replaced by radio systems.

Have seen these lighting installations up close, on the ground? 

Do you have any pictures that you could post on the Web? If not,
please describe the lights and their surroundings:

1. How many lights are in a given installation?
2. Are the lights within a fenced-off area? What kind of fence? Any
barbed wire on top?
3. How large is the enclosed area? Is it surfaced with dirt, grass,
gravel, asphalt, etc.?
4. Is there a vehicular road (or foot trail) going in to the lights?
5. How big are are the individual lights?
6. Are they arranged in any kind of pattern, shape, or line?
7. How are the lights mounted? On wooden poles or metal masts to stay
above snow during winter? How high? What color are the poles/masts?
8. Do they have any shades, cones, or housings that only direct their
light upwards, or do they also illuminate the ground (like a street
9. Is there any type of small support shed or building near the
lights? What color is it?
10. There are no antennas at all near the lights?
11. Are there power lines for the lights? Solar panels?
12. Do the lights look old and worn, or would you say they are
maintained in good condition?

Sorry to bombard you with questions. Now, if you would like to fly us
over to beautiful Norway, we would be more than happy to look for
ourselves... ;-)


Request for Question Clarification by thx1138-ga on 31 Jul 2002 07:02 PDT
Maybe if you can tell us the name of the airport someone with Flight
Simulator 2002 can ‘fly over’ and have a look ? :)

Clarification of Question by blazius-ga on 31 Jul 2002 13:39 PDT
For huntsman-ga:

1. As far as I can tell, there are just two light in each location,
but these are mounted very close to each other.  I guess one of them
acts as a spare for the other.

2. The light are not fenced in.

3. It is just cut a small clearing (a few meters) around the lights,
only enough to prevent moving/falling trees from damaging it.  The
ground has a natural appearance.

4. Some lights are located near roads, while some can only be reached
by a footpath, a boat or a helicopter.

5./7. The light fixtures are approx 30x40 cm, and they are mounted on
7-8 m high wooden poles.  The poles are treated with a tar-like
substance (like most other outdoor wooden poles).

6. The lights in question does not create any obvious pattern.  Thre
may of course be lights I do not know of that can contribute to a
pattern. The lights seem to ble at lest a few hundred meters apart.

8. The housing directs most of the light upwards, but it is easy to
see stray light when standing below any of the lights, even quite far
away.  The lights that are near roads have shades to prevent
disturbing nighttime drivers.

9. There are no builidngs close to the lights, apart from small
transformer boxes.

10. There are no visible antennae at all near the lights.

11. As far as I have seen, all the lights are connected to an external
power supply via power cables in the ground or in the air.

12. The lights seem to be well maintained.

I do not have access to a digital camera, so providing pictures online
could take some time...

Request for Question Clarification by huntsman-ga on 05 Aug 2002 15:39 PDT

I think I know what the lights are, but I need to ask just a few more

1. What Norwegian city is the airport in? 

2. What is the name (and three-letter identifier) of the airport? For
example, Forenbeu Airport in Oslo is designated as "FBU", Trondheim
Airport as "TRD", etc.
3. You said it was a civilian and military airport. Does it handle
international passenger service -- large multi-engine SAS or United
pasenger jets -- or just smaller private planes?

Subject: Re: Lights near airports
Answered By: huntsman-ga on 05 Aug 2002 21:15 PDT
Rated:4 out of 5 stars

Thanks to an obscure UseNet newsgroup post archived by Google Groups
(, I have found the answer to your mystery
ground lights.

They are "circling lights" used at Norwegian airports. 

Mountainous terrain around airports can make approaches from certain
headings difficult or dangerous, particularly in bad weather
conditions. To ensure a safe approach, Norwegian airports use a series
of ground lights, laid out in arcs, that safely guide the pilot in a
specific flight path to the end of the runway.

Because circling lights describe curved paths that are only visible
from the air, individual lights may appear to be randomly placed when
seen from the ground.

Note the following nine-year-old newsgroup post (in Google Groups):

"From: Lars-Henrik Eriksson (
Subject: Re: Navigation by ground lights? (non-empty this time!) 
Newsgroups: rec.aviation.misc
View: Complete Thread (4 articles) | Original Format 
Date: 1993-04-04 05:55:39 PST 
"...Many Norwegian airports use an extensive circling light system.

Often, the airport is located deep in a fiord, so there is only one
approach direction - over the fiord. Should the wind blow the wrong
way, circling to the other runway can be really hairy at night or in
poor visibility conditions. To facilitate, there is a system of
circling lights that defines the proper flight path.

The most amazing example I've seen is the localiser approach to Mo i
Rana. The localiser leads to a place about 2.5 nautical miles from the
airport - the missed approach point is 2 miles further away, and a 120
degree turn is required to line up with the nearest runway. Six
circling lights are used to define the route from the MAP to the
threshold. Should a landing in the opposite direction be required,
four additional circling lights defines a teardrop-like manouver from
the airport to threshold of the opposite runway."

I found a flight simulator chart of Norway's Mo i Rana airport
mentioned in the newsgroup post above. Note how a pilot encounters the
radio marker first, then follows a series of red "circling lights"
(red diamonds) to the runway (yellow band):

   Russvoll, Mo I Rana (Norway)

Red lights are used at Mo I Rana for the highest night visibility.
Note the 3D airplane illustration: if the pilot missed the red
circling lights, there's a good chance he would impact the mountain to
the right of the airport. The width of the circling path is slightly
more than one-half nautical mile (1000 meters, about 3200 feet), so
there's not much room for error.

Here is a less extreme airport example with white circling lights
defining circular approaches on both sides of the runway:

   Valan, Honningsvag (Norway)

This airport uses red and white circling lights:

   Sorkjosen, Sorkjosen (Norway)

For additional details, I suggest that you contact the Norwegian civil
air authority:


The United States' Federal Aviation Administration has some additional
Norway aviation information and links here:

   FAA International Flight Information 
   Country Information 

FYI, the FAA's master list of civil aviation authorities of countries
around the world is here:

   Civilian Aviation Authorities of the World

Although I did not see anything about "circling lights" on their Web
site, the major international aviation organization is:

   International Civil Aviation Organization - ICAO

"One of ICAO's chief activities is standardization, the establishment
of International Standards, Recommended Practices and Procedures
covering the technical fields of aviation: licensing of personnel,
rules of the air, aeronautical meteorology, aeronautical charts, units
of measurement, operation of aircraft, nationality and registration
marks, airworthiness, aeronautical telecommunications, air traffic
services, search and rescue, aircraft accident investigation,
aerodromes, aeronautical information services, aircraft noise and
engine missions, security and the safe transport of dangerous goods.
After a Standard is adopted it is put into effect by each ICAO
Contracting State in its own territories."

A list of ICAO member nations can be seen here (Norway is among them):

   ICAO Contracting States (188)
   (As of 20 June 2002)

If you would like to find out additional ICAO information, here is
contact information for their European regional office:

   ICAO, European and North Atlantic Office 
   3 bis villa Émile-Bergerat, 
   92522 Neuilly-sur-Seine 
   Cedex, France 
   Tel: + 33 1 46 41 85 85
   Fax: + 33 1 46 41 85 00 

I appreciate your question: you are not the only one who learned
something new about international aviation.


Search Terms & Google Results:

   night runway approach ground lights

   norway "circling lights"

   airport landing lights 

   airport runway lights

   airport lighting standards

Clarification of Answer by huntsman-ga on 06 Aug 2002 07:34 PDT

Have you contacted the airport directly?


Request for Answer Clarification by blazius-ga on 20 Aug 2002 12:04 PDT
[This is not a request for answer clarification, it is rather a reply
to huntsman-ga.]

I have contacted the airport several times, but I have not beeen able
to get an answer more detailed than "navigation lights".  I'll post it
here if I find out anything more.

Clarification of Answer by huntsman-ga on 21 Aug 2002 03:05 PDT

Over and out,
blazius-ga rated this answer:4 out of 5 stars
Your answer is likely to be correct, but I am unable to confirm that
it is valid for the particular airport in question.  I'have tried to
get information on these lights from the norwegian CAA, but they have
not given me an answer (so far).

Any way, you have put so much effort in answering the question that
you really deserve the lousy $5 I offered.  I expected that the
question would be quite easy, but understand that it was harder than I

Subject: Re: Lights near airports
From: thx1138-ga on 30 Jul 2002 12:28 PDT
This question is bugging me!  

I canīt find anything that fits the description you gave, althought it
sounds like itīs some kind of Visual Approach Slope Indicator  (but
they are situated close to the runway)

Visual Approach Slope Indicator (VASI) 
“The VASI is a system of lights so arranged to provide visual descent
guidance information during the approach to a runway. These lights are
visible from 3-5 miles during the day and up to 20 miles or more at
night. The visual glide path of the VASI provides safe obstruction
clearance within plus or minus 10 degrees of the extended runway
centerline and to 4 NM from the runway threshold. Descent, using the
VASI, should not be initiated until the aircraft is visually aligned
with the runway. Lateral course guidance is provided by the runway or
runway lights”

This website: seems
to give ALL the types of guidance light ing for runways but what you
described is not there.

Good Luck.

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