Calling all aircraft experts : plane headlights

david25 · 13 Aug 2013 at 15:41

Hello, here is an strange question;

I was trying to take photos of the Perseid meteor showers last night unfortunately I didn't see any. But it gave me a chance to look at all the aircraft flying overhead.

Normally, they have red, green flashing lights, but I swear I saw one switch on "headlights". I am going mad? I live about 40 miles away from Stansted.

WillyNelson · 13 Aug 2013 at 15:42

Landing lights. Enables them to see the runway in the dark, and the ATC to see the plane.

agnes · 13 Aug 2013 at 15:42

The 'headlights' are on all the time. What you saw is the plan go through a cloud.

Mat · 13 Aug 2013 at 15:43

Headlights in the undercarriage

david25 · 13 Aug 2013 at 15:50

agnes said:
The 'headlights' are on all the time. What you saw is the plan go through a cloud.

I definitely think they switched on, I was looking at the flashing lights and then a bright constant light appeared.

Is this part of their landing process?

david25 · 13 Aug 2013 at 15:51

Mat said:
Headlights in the undercarriage

When do they extend the undercarriage, I am miles away from Stansted.

agnes · 13 Aug 2013 at 15:52

david25 said:
I definitely think they switched on, I was looking at the flashing lights and then a bright constant light appeared.

Is this part of their landing process?

Ah, hmmm. Probably is then.

james_2k · 13 Aug 2013 at 15:53

the 'headlights' are not on all the time.

the red and green lights are nav lights (on the wingtips), which are on all the time and dont flash

the red flashing lights are the beacons and they are on whenever the engines are or are about to be turned on (generally one above and one below the fuselage).

the white flashing lights or strobes (wingtips), are generally on when the aircraft is on the runway to when it leaves again at the destination.

you also have taxi lights (landing gear generally) and landing lights (landing gear/wings). which are similar, we switch our landing lights on when cleared for take off and off during the climb out, back on again when doing approach checks.

similar process for the taxi lights.

p.s. the landing lights have a very tight 'cone' of light, so that they can be seen a long way away and give the correct illumination on landing etc. so it is possible that it just turned towards you.

hamesy · 13 Aug 2013 at 15:54

I think under 10,000ft they have to turn their handing lights on.

james_2k · 13 Aug 2013 at 15:56

thingemajib · 13 Aug 2013 at 16:11

hamesy said:
I think under 10,000ft they have to turn their handing lights on.

^this. Cant remember the exact details but if its over a certain weight/passenger seat count then they must have their landing lights (ie headlights) on at all times below 10000 feet, regardless of the weather/time of day. Typical airliners have 1 light at the front of each wing close up by the fuselage, 1-2 in the nosewheel structure and some planes have extra ones that pop out under the fuselage if the vis is low and the pilots are struggling to see the runway (think of them as hi-beams!)

Heres the best non-fsx pic i could find:

david25 · 13 Aug 2013 at 16:12

james_2k said:
the 'headlights' are not on all the time.

the red and green lights are nav lights (on the wingtips), which are on all the time and dont flash

the red flashing lights are the beacons and they are on whenever the engines are or are about to be turned on (generally one above and one below the fuselage).

the white flashing lights or strobes (wingtips), are generally on when the aircraft is on the runway to when it leaves again at the destination.

you also have taxi lights (landing gear generally) and landing lights (landing gear/wings). which are similar, we switch our landing lights on when cleared for take off and off during the climb out, back on again when doing approach checks.

similar process for the taxi lights.

p.s. the landing lights have a very tight 'cone' of light, so that they can be seen a long way away and give the correct illumination on landing etc. so it is possible that it just turned towards you.

Interesting, thanks. The planes fly right over my house.

How far away from the airport (in miles) do you go through the approach checks?

david25 · 13 Aug 2013 at 16:14

thingemajib said:
^this. Cant remember the exact details but if its over a certain weight/passenger seat count then they must have their landing lights (ie headlights) on at all times below 10000 feet, regardless of the weather/time of day. Typical airliners have 1 light at the front of each wing close up by the fuselage, 1-2 in the nosewheel structure and some planes have extra ones that pop out under the fuselage if the vis is low and the pilots are struggling to see the runway (think of them as hi-beams!)

Interesting, is it a manual switch or like a car with auto-lights and a sensor?

thingemajib · 13 Aug 2013 at 16:26

david25 said:
Interesting, is it a manual switch or like a car with auto-lights and a sensor?

Manual switch.

I've actually just read up on the matter a bit, seems im a bit wrong. Apparently there is no set law about when the lights should be on or off. The 10000ft thing is an advisory made by many governing bodies and is up to the individual airline whether to enfore it in their Standard Operating Procedures or not (which most do).

Whilst i have no real life airline experience I did do a two week couse on a 737 sim and we had the 10000ft rule in our fictional airlines SOPs

james_2k · 13 Aug 2013 at 16:33

david25 said:
Interesting, thanks. The planes fly right over my house.

How far away from the airport (in miles) do you go through the approach checks?

well it varies between airlines but we do it when cleared to an altitude on approach (when we transition from flight levels to local pressure basically)

so generally speaking. 30/40 miles or so from the airport.

but as thingemajib says, it seems to vary by operator. we dont have to turn anything on at 10,000 feet. well we generally do in the climb, but that's the seatbelt sign.

thingemajib said:
Manual switch.

switches*, one for each side

also I have never heard of the pop out one but im sure they are around, if the vis is that bad anyway chances are the landing lights are off. because as most people know, you dont want your full beams on in the car. same as a plane

david25 · 13 Aug 2013 at 16:36

james_2k said:
well it varies between airlines but we do it when cleared to an altitude on approach (when we transition from flight levels to local pressure basically)

so generally speaking. 30/40 miles or so from the airport.

but as thingemajib says, it seems to vary by operator. we dont have to turn anything on at 10,000 feet. well we generally do in the climb, but that's the seatbelt sign.

switches*, one for each side

also I have never heard of the pop out one but im sure they are around, if the vis is that bad anyway chances are the landing lights are off. because as most people know, you dont want your full beams on in the car. same as a plane

That would be about right then, I live about 40 miles away from Stansted, they must come over the North sea, start their decent and just by luck my house is at 10,000 feet!

Cosimo · 13 Aug 2013 at 16:39

Both landing and navigation lights can been seen.

james_2k · 13 Aug 2013 at 16:39

your house is at 10,000 feet?? :O impressive! heheh

last time we landed in Stansted it was in a cargo aircraft and i was puking all over the back while the capt was flying. not my finest hour

Cosimo said:
Both landing and navigation lights can been seen.

and the strobes and the beacon

Scougar · 13 Aug 2013 at 16:47

Used to see planes with their landing lights on all the time (What you are describing as headlights) on approach to Plymouth Airport.

david25 · 13 Aug 2013 at 17:03

james_2k said:
your house is at 10,000 feet?? :O impressive! heheh

Well I mean, the planes are just crossing the 10,000 boundary overhead.

Thanks for the help everyone.