View Full Version : Use of Position and Strobes

23rd Sep 2005, 13:37
I am wonder what the normal use of position lights (nav) and strobes are. I often see aircraft with the red and green position lights on for hours before departure, do these go on when the APU is fired up and strobes when entering the runway?

Thank you.

Flying Fiona
23rd Sep 2005, 13:41
Position lights should only be used for night operations. They have no effect during daytime and during poor visibility. Put them on at night and turn them off during the day. Simple!

23rd Sep 2005, 14:19
That's not standard practice in my company and certainly not in most other companies judging from a quick glance around the apron today.

Our company SOP is for position lights to be on all the time electical power is available to power them.

Anti-collision (reds) on just before pushback and off after engines are shut down on stand.

Strobes (whites) on as the aircraft enters any active runway and off as it exits an active runway.

23rd Sep 2005, 14:33

That is exactly what I have been seeing as well.
The Nav lights kind of say, "This machine is alive"

23rd Sep 2005, 14:44
Nav light switch is never turned off on our aircraft. As soon as electrical power is applied to aircraft, whether internally or externally, the nav lights are on. Beacons go on with the first engine spooling over and strobes go on entering the runway for departure, off exiting the runway after landing. This is pretty much SOP amongst most operators on this side of the pond.

23rd Sep 2005, 22:24
I think the UK military also have nav lites on at all times as SOP - extra collision avoidance?

23rd Sep 2005, 23:31
Lol, I think Flying Fiona was thinking about the procedures in light aircraft:O

Flying Fiona
23rd Sep 2005, 23:52
Have a look around chaps during the day. Now tell me what you see first. The nav lights or the Aircraft???

Many Airlines around the world don't use Nav lights for day light ops. Whats the point?

Now check the ANO and see when Nav lights should be used. I cant find anything about them being used during the day.

I tell you what, lets put are lights on every time we drive are cars!

If its SOP use them. But if it isn't DON'T.

Old Smokey
24th Sep 2005, 03:01
For our operation -

Nav lights ON when it's dark. OK, if you leave them on all day, there's no problem other than shortening the bulb life.

Beacons ON just prior to engine start, and OFF after spool-down. This is advertising to the world that an engine or moving aircraft danger exists. Beacon is also ON during tow to indicate aircraft movement.

Strobes ON when entering the runway, OFF immediately upon exit (This includes any time that I'm crossing a runway). This is advertising to the world that 'I have the runway'. If, on approach, I see an aircraft at the holding point with strobe lights ON, I have only one reaction - Go Around!

Perhaps a little naively, I thought that this was universal.


Old Smokey

24th Sep 2005, 13:45
Well, I was just really pointing out what happens in practice rather than what the ANO or other legislation requires. In 'our' airline we have the position lights on all the time.

24th Sep 2005, 22:13
And if I understand correctly, the logo and wing lights are also off when at the gate or taxiing to avoid excessive bright lighting which may blind/distract other pilots and are on (optionally I think) when entering the runway.

Is this correct?


24th Sep 2005, 23:07
Again it tends to depend on a particular company's SOPs. Our SOP is that the nose wheel light goes on for taxy on departure. Then wing landing lights on when cleared for take off. All landing lights are turned off passing 10000'/FL100 in the climb. Passing 10000'/FL100 in the descent the wing lights go on and the nose light goes on when cleared to land. Wing lights then turned off leaving the runway and nose light off when no longer required, usually turning onto stand. The logo light just tends to get turned on when it gets dark...

Also as you suggest it's pilot's discretion to turn lights off when they become a nuisance to other pilots, e.g. at the holding point with the nose light on.

Capt Claret
25th Sep 2005, 04:41
Fiona, one might see the aircraft before seeing the nav lights but amongst the din of an apron one mightn't know that the aircraft has an APU running, or could be getting close to starting.

In previous lives, as others have attested above, NAV lights are on when the PU is to be started or ruinning. Let's others know that the ship is powered, and could start without too much notice.

Re driving with lights on. I average about 30,000km/year. Much of it country, highway driving with lights on day and night. An oncoming vehicle with lights on is much easier to identify than one without, and, in 20 years of drving thus, I wouldn't have replaced more than half a dozen headlights/globes.

25th Sep 2005, 04:49
System layout also mandates which lights are on & when. The NAV (Position) lights are normally on the Service Bus & on at all times there is power available to the aircraft. You don't notice them indaylight owing to the relatively low intensity.

Most authorities require the Flight Data Recorder to be on prior to engine start. To the best of my knowledge, all Boeings and most Bombardier aircraft do this by slaving the FDR ON to both of the Strobe lights and adding Beacon Lights ON (Red Strobes) as part of the pre-start checklist. The brighter, white, Strobes (normally refered to as Anti-Collision lights in most AFMs) are only switched on after takeoff clearance is given (as above).

BTW if you follow common military practice & switch off all strobes prior to shut down, you'll probably get a "No Fault Found" maintenance hit on a commercial jet as the FDR won't be communicating with the FDAU (or DCU on the CRJs & 604s) and the Maintenance Diagnostic Computer will log it.

26th Sep 2005, 00:45
"I tell you what, lets put are lights on every time we drive are cars!"

What a good idea! I guess that is why in this country all cars manufactured, starting with model year 1990, have been required to have daytime running lights come on automatically.


26th Sep 2005, 10:15
It was my understanding that the red anticols are turned on as soon as the aircraft's hydraulics are powered... at least this was my experience during my maintenance work (767s, MD11s) where it would be done inside the hangar to warn the personnel working there to keep clear of the landing gear, flaps and other bits that have the potential to mangle people simply by pulling a lever on the flightdeck.

So am I correct in assuming during normal operations it's done only when the first engine starts spooling up during or after pushback (the hyd demand pumps already powered)?

Gary Lager
26th Sep 2005, 10:21
Sort of correct - Red anti-collision on before engine start or before moving on the pan (pushback, towing).

It stays on after shutdown until engines have run down below a specified min N1 (usually about 4-5%). The ground crew then know it is safe to approach the aircraft.

26th Sep 2005, 12:13
In our SOPs the first officer's before start overhead panel scan goes like this:

Pressurise hydraulics - fuel pumps on - packs off - anti-collision (red) lights on.

So obviously the hydraulics pressurise a split-second before the lights go on in our case - but all of this certainly happens before the push back is started or an engine turned.

Loop... Hole
26th Sep 2005, 12:32
If, on approach, I see an aircraft at the holding point with strobe lights ON, I have only one reaction - Go Around!

I have often been given an "After the landing XX line up and wait behind" clearance at busy airports, mostly during tight take-off/landing sequencing. This will trigger the line-up checklist and item 3 is "Anti coll - white". I have therefore been at the hold with white flashing and no-one's gone around on me yet. Is it only a matter of time?

26th Sep 2005, 13:05
read FAA AC 120-74a a snippet posted below
8. USE OF EXTERIOR AIRCRAFT LIGHTS TO MAKE AIRCRAFT MORE CONSPICUOUS. a. General. (1) Exterior aircraft lights may be used to make an aircraft operating on the airport surface more conspicuous. Pilots may use various combinations of exterior lights to convey their location and intent to other pilots, air traffic control, and ground personnel. Certain exterior lights may also be used in various combinations to signal whether the aircraft is on a taxiway or on a runway, in position on the runway but holding for takeoff clearance, crossing an active runway, or moving down the runway for takeoff. (2) Because adherence to the guidelines in this AC are voluntary and aircraft equipment varies, flightcrews are cautioned not to rely solely on the status of an aircraft’s lights to determine the intentions of the flightcrew of the other aircraft. Additionally, flightcrews must remember to comply with operating limitations on the aircraft’s lighting systems. b. Exterior Lights. To the extent possible and consistent with aircraft equipage, operating limitations, and flightcrew procedures, pilots should illuminate exterior lights as follows: (1) Engines Running. Turn on the rotating beacon whenever an engine is running. (2) Taxiing. Prior to commencing taxi, turn on navigation, position, anti-collision, and logo lights, if available. To signal intent to other pilots, consider turning on the taxi light when the aircraft is moving or intending to move on the ground, and turning it off when stopped, yielding, or as a consideration to other pilots or ground personnel. Strobe lights should not be illuminated during taxi if they will adversely affect the vision of other pilots or ground personnel. (3) Crossing a Runway. All exterior lights should be illuminated when crossing a runway. CAUTION: Flightcrews should consider any adverse effects to safety that illuminating the forward facing lights will have on the vision of other pilots or ground personnel during runway crossings. (4) Entering the departure runway for takeoff or “position and hold.” When entering a runway either for takeoff, or when taxiing into “position and hold,” flightcrews should make their aircraft more conspicuous to aircraft on final behind them and to ATC by turning on lights (except for landing lights) that highlight the aircraft’s silhouette. Strobe lights should not be illuminated if they will adversely affect the vision of other pilots.
Page 14 Par 7
9/26/03 AC 120-74A
(5) Takeoff. Turn on landing lights when takeoff clearance is received, or when commencing takeoff roll at an airport without an operating control tower. NOTE: The SOP of turning on landing lights when takeoff clearance is received is a signal to other pilots, ATC, and ground personnel that the aircraft is moving down the runway for takeoff.

PPRuNe Radar
26th Sep 2005, 14:09
I tell you what, lets put are lights on every time we drive are cars!

Buy a SAAB or Volvo and it happens without any intervention ;)

26th Sep 2005, 15:04
Where I fly, navlights are turned on even during daytime to show that someone - be it flightcrew or mechanic - is onboard the aircraft.

26th Sep 2005, 20:24
Regardless of what I think about using the position lights during daylight ops, I am required to comply with our FAA approved Ops manual. I suspect all US airlines have the same requirement as my company. Here is a copy & paste of the page in our Ops Manual:

Exterior Lights Usage:

Exterior lights should be used in accordance with the following guidance, and consistent with specific aircraft equipment, limitations, and procedures.

Phase of Flight Lights Usage:

Aircraft is powered - Navigation/Position lights

Engines running/aircraft moving:

Anti-collision lights (Beacons)
• On immediately prior to aircraft movement, or
immediately prior to engine start (if starting at gate).


Taxi light
• On when moving or intending to move; off when

Crossing a runway:

All exterior lights
• Avoid using landing lights if they will adversely affect
the vision of other pilots.

Position and hold:

All exterior lights (except landing lights)
• Avoid using strobes if they will adversely affect the
vision of other pilots.


All exterior lights
• Turning on the landing lights is a signal that the
aircraft is commencing takeoff roll.

In flight (below 18,000 feet):

All exterior lights
• Conditions permitting, all exterior lights are normally

28th Sep 2005, 06:55
Most countries in Northern Europe require to have car headlights on when outside densely populated areas, depicted by as sign so you know when you are entering or leaving one. Most just leave lights on all the time. So I must agree I have changed some 2 or 3 bulbs in 15 years or so.

Regarding aircraft lights. NAV's are left on all the time day and night. Wing and wheel well lights for external inspection and strobes when entering a runway. These are SOP items. Logo light is not an SOP item, but if the aircraft is equipped with one I use it as it improves visibility.


t6 sparky
29th Sep 2005, 10:08
Most authorities require the Flight Data Recorder to be on prior to engine start. To the best of my knowledge, all Boeings and most Bombardier aircraft do this by slaving the FDR ON to both of the Strobe lights

I'm sorry but your knowledge is incorrect. I don't know about Bombardier aircraft but on boeings the FDR is turned on by either air/ground sensing, engines starting or running, or for testing purposes. Strobe light (white lights)or indeed Anti-collision (red lights) switching has no input whatsoever into FDR.

1st Oct 2005, 06:30
That may be true for older Boeings (the BAC 1-11 had a basic "FDR ON" switch on some models). The WoffW function is the back-up path for the 767 at least (or it was when I was in 40-01 Building at Everett). It's only turns the FDR on if the crew haven't carried out the checklist item.

Don't confuse the ON discrete and/or power switching with the Record Inhibit discrete that has to be much more complex now that straight forward g-switches are not allowed to shut off recording. Comes from some incidents where aircraft continues flying for some time after a hard landing/ground impact and then goes down but with no FDR recording.

Old Smokey
2nd Oct 2005, 13:54
Loop... Hole,
My quote............
If, on approach, I see an aircraft at the holding point with strobe lights ON, I have only one reaction - Go Around!
Your quote..........
I have therefore been at the hold with white flashing and no-one's gone around on me yet. Is it only a matter of time?
Yes, I think that it's only a matter of time. It's pretty much universal in the 2 airlines that I've worked for.

If I get a clearance "After the landing XX line up and wait behind", it's hands OFF the Strobes, Landing Lights etc. until the landing aircraft has passed our position at the hold. Then it's turn everything ON, get on the runway, and wait your Takeoff clearance.


Old Smokey