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BreninTW
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Flashing White Rear Lights

Mon Nov 24, 2014 3:47 am

Last weekend I happened to be at TSA and I saw a JL 787 departing. One thing that caught my attention was two white strobes at the back, on each side of the APU exhaust.

I've never noticed them before, even on NH's 787s. Are they commonly fitted or were they customer-specified?
 
rendezvous
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 4:05 am

Most transport aircraft have strobes are the rear (flashing white). The 787 might have two so it can be seen from the required directions.
 
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BreninTW
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 6:04 am

Quoting rendezvous (Reply 1):

Thanks -- never noticed them before.
 
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MD80
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 7:27 am

What´s the reason for using flashing white instead of - for example red?

There must be a reason for selection of the colors and I compare this with aircraft warning lights at TV Towers in Germany: During daylight "white strobes" and during night "red beacons".

Thanks
Dedicated to the MD-80, MD-90, MD-95, and DC-9: www.MD-80.com
 
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7BOEING7
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 4:11 pm

Modern airplanes have "beacon/anti-collision" lights -- top and bottom RED strobes (used to be rotating lights), "navigation position" lights -- front wing tip GREEN (right)/RED (left) (just like a boat so you can tell which way it going at night) and rear wing tip WHITE. To increase daylight visibility WHITE strobe lights have been added to the wingtips and tail -- due to the geometry of the tail cone/APU exhaust on the 787 there is one on each side.
 
AIRWALK
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 4:43 pm

Quoting MD80 (Reply 3):
What´s the reason for using flashing white instead of - for example red?

There must be a reason for selection of the colors and I compare this with aircraft warning lights at TV Towers in Germany: During daylight "white strobes" and during night "red beacons".

All the Navigation Lights are positioned in a way that other aircraft can get a general idea of the direction you are travelling in and whether a collision risk exists as well as establishing who has right of way. Each light has a specific angle you can see it from. For example the port wing has a red nav light. It is visible from dead forward to approx 110 degrees circling around. Depending on what lights you can see you can establish an idea of where the A/C is and the direction its heading in without use of systems such as TCAS.
I'm sure this thread will take off soon
 
26point2
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 11:11 pm

The aircraft I fly, Global Express, has strobe lights of course and a 3 position Anti-Collision Light switch. OFF-RED-WHITE. I have only ever used OFF or RED. Not sure why we have a WHITE option. I vaguely recall someone at BBD mentioning that some nations require white anti-collision lights?
 
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Starlionblue
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RE: Flashing White Rear Lights

Mon Nov 24, 2014 11:37 pm

Quoting MD80 (Reply 3):


There must be a reason for selection of the colors and I compare this with aircraft warning lights at TV Towers in Germany: During daylight "white strobes" and during night "red beacons".

Typically red lights at the top are for the less high obstacles (under 45m). Medium and tall towers and masts normally have white flashing lights at the top (and red lights lower down), with taller obstructions having brighter lights that flash more often.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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MD80
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 2:40 am

Quoting AIRWALK (Reply 5):
All the Navigation Lights are positioned in a way that other aircraft can get a general idea of the direction you are travelling in and whether a collision risk exists as well as establishing who has right of way. Each light has a specific angle you can see it from. For example the port wing has a red nav light. It is visible from dead forward to approx 110 degrees circling around. Depending on what lights you can see you can establish an idea of where the A/C is and the direction its heading in without use of systems such as TCAS.

Thank you!

Quoting Starlionblue (Reply 7):
Typically red lights at the top are for the less high obstacles (under 45m). Medium and tall towers and masts normally have white flashing lights at the top (and red lights lower down), with taller obstructions having brighter lights that flash more often.

Thanks. IIRC; it depends on regions and your description explains the way in North America IIRC.

Red lights (including red beacons with much higher intensity) seem to be the norm in Germany at high obstacles. During daylight, such high obstacles have white strobes but during night red beacons.

Here is a visuel example from the TV Tower of Berlin/Germany. Go to approx. 0:50 and watch the change from white to red:

https://www.youtube.com/watch?v=A3epXRMxxRs

Nevertheless the question remains (and back to aircraft!) why warning lights are white strobes and not for example red strobes or pink or green.

It seems correct that beacons and strobes operate at their "intervals" to generate a higher attention for the viewer instead of a permanently white or red light, right?

So, why are white strobes white? 

The anti-collision beacon on aircraft is mostly red and not a flashing strobe IIRC.

Thanks for answers!
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timz
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 3:04 am

Quoting rendezvous (Reply 1):
Most transport aircraft have strobes are the rear (flashing white)

Traditionally the rear light/lights were steady white. When did "most" transports start to get flashing white on the tail?
 
rendezvous
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 5:29 am

Quoting timz (Reply 9):
When did "most" transports start to get flashing white on the tail?

Hmm good question. My observations are probably mostly more modern types such as the Boeing 777. I had a look at some videos, it appears many do not have rear white strobes, but 747-400, 777, 787, A330, A340, A380 do. The Dash 8 I fly does as well.
 
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7BOEING7
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 5:56 am

Quoting MD80 (Reply 8):
The anti-collision beacon on aircraft is mostly red and not a flashing strobe IIRC.

On Boeing aircraft anti-collision lights have been red strobes for many years instead of red "rotating beacons".

Quoting timz (Reply 9):
Traditionally the rear light/lights were steady white. When did "most" transports start to get flashing white on the tail?

About 40 years ago, but we're sort of talking apples and oranges. You have the white position lights which on smaller aircraft are only on the wings (737/757) and on larger aircraft are also on the tail (747/767/777/787). On older 747's there were two tail position lights, one outboard on each horizontal stabilizer -- on the 787 there are also two on either side of the tail cone. A separate switch controls the white "strobe" lights which are on the wing tips and also the tail (two on the 787) for better daylight visibility.
 
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barney captain
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 6:28 pm

We were behind an HA A330 on a dark ramp one night. I was amazed how difficult it was to see due to the fact that there were no white position lights facing aft from the wing tips. The only light visible was a single white light on the tail cone - making tips of the wings nearly invisible.
Southeast Of Disorder
 
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DocLightning
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RE: Flashing White Rear Lights

Tue Nov 25, 2014 7:56 pm

Quoting 7BOEING7 (Reply 4):
Modern airplanes have "beacon/anti-collision" lights -- top and bottom RED strobes (used to be rotating lights), "navigation position" lights -- front wing tip GREEN (right)/RED (left) (just like a boat so you can tell which way it going at night) and rear wing tip WHITE. To increase daylight visibility WHITE strobe lights have been added to the wingtips and tail -- due to the geometry of the tail cone/APU exhaust on the 787 there is one on each side.

The other thing is that the 787 uses LED lights that have a longer "on" cycle than the strobes used on older types. Rather than a quick flash, the 787's beacons actually stay on for a good portion of a second before shutting off again.

The DC-9's had a strange beacon. Rather than blinking, their beacons rotated kind of like an old-fashioned cop car, but back and forth, rather than straight rotation.
-Doc Lightning-

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Max Q
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RE: Flashing White Rear Lights

Wed Nov 26, 2014 1:49 am

Older B727's had rotating Nav lights !



The red and green wingtip lights actually rotated within the nav light enclosure.
We had a three position switch, OFF, ROTATE or STEADY.



Kind of unusual, we had them on our old People Express and Delta Aircraft if I remember right.
The best contribution to safety is a competent Pilot.


GGg
 
shamrock137
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RE: Flashing White Rear Lights

Sat Nov 29, 2014 2:34 am

Quoting Max Q (Reply 14):
The red and green wingtip lights actually rotated within the nav light enclosure.

NW DC-9's had the same system up until retirement.

Quoting 26point2 (Reply 6):
The aircraft I fly, Global Express, has strobe lights of course and a 3 position Anti-Collision Light switch. OFF-RED-WHITE. I have only ever used OFF or RED. Not sure why we have a WHITE option. I vaguely recall someone at BBD mentioning that some nations require white anti-collision lights?

Usually red is used on the ground, white in the air. The Q400 has a similar system, on the ground the red beacon flashes, but when entering a runway the white strobes on the tail and belly come on instead when the switch is changed form red to white.

Quoting MD80 (Reply 3):
What´s the reason for using flashing white instead of - for example red?

They have evolved to be used at different phases of flight. From engine start to engine shutdown, the red beacon strobes, usually on the top and bottom if the fuselage as a warning "This aircraft may move at any time and may have then engines running stay clear." Ramop workers are usually taught not to approach an aircraft with a flashing red beacon light or drive behind it unless you get the all clear that the engines are off and brakes set.

The white lights are used when entering and crossing an active runway and during flight. Previously they were only used from takeoff to touchdown, but as a measure to raise awareness of aircraft on runways, they are now used when crossing runways while taxing.

As a bit of extra info, the A320 strobes have a three position switch, OFF, AUTO and ON. The auto function turns on the strobes as the aircraft takes off. I think the DC-9 had a similar feature.
Time to spare? Go by air!
 
diverted
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RE: Flashing White Rear Lights

Sat Nov 29, 2014 1:44 pm

Quoting Shamrock137 (Reply 15):
They have evolved to be used at different phases of flight. From engine start to engine shutdown, the red beacon strobes, usually on the top and bottom if the fuselage as a warning "This aircraft may move at any time and may have then engines running stay clear." Ramop workers are usually taught not to approach an aircraft with a flashing red beacon light or drive behind it unless you get the all clear that the engines are off and brakes set.

The white lights are used when entering and crossing an active runway and during flight. Previously they were only used from takeoff to touchdown, but as a measure to raise awareness of aircraft on runways, they are now used when crossing runways while taxing.

Can't speak for other types, but I know the Q400 has a flight/taxi switch for the strobes. When the aircraft is on the ground, it's a red anti collision beacon on the top of the fuselage; When entering the runway, it's switched to "flight" which turns on the 2 white strobes (one on the tail, one on the bottom of the fuselage)

The white strobes are turned off after going through 10,000ft, and are turned back on when descending through 10,000
 
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shengzhurou
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RE: Flashing White Rear Lights

Sun Dec 07, 2014 5:15 am

787 have two tail nav lights and strobe lights .
on 767-400 one side is the regular white tail nav light and other side is the strobe light.
Sheng Zhu Rou
 
shamrock137
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RE: Flashing White Rear Lights

Sun Dec 07, 2014 11:05 am

Quoting diverted (Reply 16):
The white strobes are turned off after going through 10,000ft, and are turned back on when descending through 10,000

I have never herd of this procedure, every aircraft I know has strobes on from takeoff to touchdown, unless its distracting in fog or clouds. This would mean the Q400 has no flashing lights during flight?
Time to spare? Go by air!
 
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MD80
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RE: Flashing White Rear Lights

Tue Dec 09, 2014 5:17 am

Quoting Shamrock137 (Reply 15):

Thanks to you and to all for all answers!
Dedicated to the MD-80, MD-90, MD-95, and DC-9: www.MD-80.com
 
psimpson
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RE: Flashing White Rear Lights

Tue Dec 09, 2014 2:27 pm

Quoting Shamrock137 (Reply 15):
As a bit of extra info, the A320 strobes have a three position switch, OFF, AUTO and ON. The auto function turns on the strobes as the aircraft takes off. I think the DC-9 had a similar feature.

Yes in the AUTO position the strobes lights are on continuously unless there is weight on the main landing gear.
 
trnswrld
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RE: Flashing White Rear Lights

Tue Dec 09, 2014 5:14 pm

Some older DC9's also had a unique lighting setup in that it's wing tips rear facing white "strobe" was actually a wig wag (back and forth) light. This may have been before strobe technology in not sure. But I remember seeing Northwest DC9's cruising over and after it passed by its aft wing tips had what more resembled police or emergency vehicle type lighting. It was nothing more than a standard incandescent bulb mounted in front of a reflector lens that moved back and forth.
 
freeze3192
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RE: Flashing White Rear Lights

Tue Dec 09, 2014 9:04 pm

Quoting diverted (Reply 16):

Can't speak for other types, but I know the Q400 has a flight/taxi switch for the strobes. When the aircraft is on the ground, it's a red anti collision beacon on the top of the fuselage; When entering the runway, it's switched to "flight" which turns on the 2 white strobes (one on the tail, one on the bottom of the fuselage)

The white strobes are turned off after going through 10,000ft, and are turned back on when descending through 10,000
Quoting Shamrock137 (Reply 18):

I have never herd of this procedure, every aircraft I know has strobes on from takeoff to touchdown, unless its distracting in fog or clouds. This would mean the Q400 has no flashing lights during flight?

So much miss-information here. The Q400 strobes are not tied to the flight/taxi switch. That switch (on the glareshield in front of the Captain) is for the spoilers only. The Q400's anti-collision lights (as well as all of the other DHC8 series) are controlled by a 3 position switch on the overhead panel grouped with the rest of the exterior lights. The 3 positions are White (most forward position), Off (middle position) and Red (aft position). Red controls the red beacon on the top of the fuselage. White controls the strobes on the belly and on the top of the tail. Red and White cannot operate simultaneously.

Regarding white going off through 10,000 feet: No airline that I know of switches the strobes off in flight. You could switch the light back to red if you're going through clouds to avoid blind yourself at night with the flash of the strobes (done this many times). You should not turn the switch entirely off during flight as this switch also enables the Flight Data recorder. When the switch is in either red or white, the FDR is recording. When the switch is turned off, the FDR is no longer recording.
"A passenger bets his life that his pilot is a worthy heir to an ancient tradition of excellence and professionalism."
 
FrmrKSEngr
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RE: Flashing White Rear Lights

Wed Dec 10, 2014 2:54 am

The navigation light configuration is a hold over from ships, Red Port, Green Starboard, white aft. From the visible combination you can tell the relative direction the ship/aircraft is traveling. If you keep your red to the opposing ship/plane's red (or green to green) you should pass safely port to port (or starboard to starboard). Green to red configuration indicates a crossing configuration and potential collision.

The red and white flashing beacons are intended to get your attention.
 
diverted
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RE: Flashing White Rear Lights

Fri Dec 12, 2014 12:03 pm

Quoting freeze3192 (Reply 22):
Regarding white going off through 10,000 feet: No airline that I know of switches the strobes off in flight. You could switch the light back to red if you're going through clouds to avoid blind yourself at night with the flash of the strobes (done this many times). You should not turn the switch entirely off during flight as this switch also enables the Flight Data recorder. When the switch is in either red or white, the FDR is recording. When the switch is turned off, the FDR is no longer recording.

AFAIK the flashing white strobes are switched off at 10,000 for exactly that reason.
 
shamrock137
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RE: Flashing White Rear Lights

Fri Dec 12, 2014 9:56 pm

Quoting diverted (Reply 24):
AFAIK the flashing white strobes are switched off at 10,000 for exactly that reason.

Exactly what reason? I have honestly never herd of any aircraft that turns off the white strobes at 10,000 ft. Are you sure you're not confusing this with the landing lights? They get turned on only when below 10,000 ft.
Time to spare? Go by air!
 
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LAXPAX
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RE: Flashing White Rear Lights

Sat Dec 13, 2014 1:00 am

Quoting Shamrock137 (Reply 25):
Exactly what reason? I have honestly never herd of any aircraft that turns off the white strobes at 10,000 ft. Are you sure you're not confusing this with the landing lights? They get turned on only when below 10,000 ft.

I have observed this many times from the pax cabin. Red strobes on for the entire flight; white strobes only switched on at a certain point when descending (didn't know it was 10,000, but that may be right). Once switched on, white strobes are left on through the landing phase, and only turned off after leaving the active runway. Presumably the inverse happens during ascent, when I'm never paying that much attention.  

FWIW, I mainly fly WN, so that is most likely where I have observed this.
"Remember, no matter where you go... there you are." -- Buckaroo Banzai
 
LimaFoxTango
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RE: Flashing White Rear Lights

Sat Dec 13, 2014 3:08 pm

Quoting freeze3192 (Reply 22):
Regarding white going off through 10,000 feet: No airline that I know of switches the strobes off in flight. You could switch the light back to red if you're going through clouds to avoid blind yourself at night with the flash of the strobes (done this many times). You should not turn the switch entirely off during flight as this switch also enables the Flight Data recorder. When the switch is in either red or white, the FDR is recording. When the switch is turned off, the FDR is no longer recording.

Irrespective of the switch, the FDR will continue to operate as long as the aircraft is in the air. WOW function.
You are said to be a good pilot when your take-off's equal your landings.
 
FrmrKSEngr
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RE: Flashing White Rear Lights

Sun Dec 14, 2014 12:21 am

Quoting LimaFoxTango (Reply 27):
FDR will continue to operate as long as the aircraft is in the air. WOW function.

I believe it is tied to WOW and Engines running (N1 > 0).
If WOW is sensed and Engines are on - FDR ON.
If WOW is sensed and Engines are off - FDR can be off
If WOW is not sensed And Engines are On - FDR ON
If WOW is not sensed and Engines are Off - FDR ON - Want to record data while the plane is a glider.

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