pflueeb
Posts: 14
Joined: Thu Jun 23, 2005 12:16 am

Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:22 am

Hello! I've been lurking on this excellent website for years now and FINALLY joined after what I saw last night.

Here in Las Vegas I saw a Southwest (WN right?) 737 coming in to land and its under-the-wing landing lights as well as the 2 lights on the nosegear were wig-wagging back and forth. Alternating slowly in a harmonized fashion.

I've never seen this in all of my years of plane watching. You see this effect on locomotives but not airplanes. Their landing lights are always in a steady burn.

What does this mean? Anybody know? Thank you and I look forward to being a member here!
 
PHLBOS
Posts: 6504
Joined: Thu Apr 01, 2004 6:38 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:32 am

I believe only WN's 733s and maybe 735s are equipped with this strobe-light feature; it's was either on Boeing's option list or WN added it (aftermarket?) for a special effect. Their 73Gs (that I've seen land at PHL) are the standard steady burn.

Welcome aboard, BTW.  Smile
"TransEastern! You'll feel like you've never left the ground because we treat you like dirt!" SNL Parady ad circa 1981
 
FlyingTexan
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:32 am

First, welcome to a.net.

Second, no alarm. Those are standard equipment on SWA jets as far as I can tell. I assume new deliveries come equipped with blinking landing lights.

As you probably know from reading this board, there are several active SWA employees and hoards of planes watchers. Perhaps some can add more detail.
"Wouldn't your boss like to fly home nonstop at 4:30 on a Friday afternoon?" -Airline Exec to Congressional Staffer
 
FI642
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:47 am

My friends at WN say it's to "scare birds"- as there are normally a lot of birds around airports. Whether or not that's true is another thing . .
737MAX, Cool Planes for the Worlds Coolest Airline.
 
DfwRevolution
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:55 am

>> (WN right?)

Correct... Southwest IATA code is WN and their NSYE stock ticker is LUV.

>> I've never seen this in all of my years of plane watching. You see this effect on locomotives but not airplanes. Their landing lights are always in a steady burn.

I was under the impression it is a conservation method. Alternating the lights extend their lives compared to burning them steady.
 
pflueeb
Posts: 14
Joined: Thu Jun 23, 2005 12:16 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 1:45 am

DFW Revolution--what you say about conservation makes sense, however why was that occurence the first time in decades of plane watching that I've seen that?

The obvious intended use of landing lights is to shine on the runway on approach. Granted, he may have switched them to steady burn at the outer marker--I don't know.

It was just really freakish to see a 737 coming in with slow alternating lights---looked kind of cool actually!

Lastly, I was thinking that perhaps it was a way of signaling the tower and/or identifying himself to another plane or helicopter (which are prominent here over the Strip doing tours).
 
USairways16BWI
Posts: 921
Joined: Tue May 11, 2004 4:58 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 2:36 am

A while back, I started a thread on the same topic.

http://www.airliners.net/discussions/general_aviation/read.main/87108

http://www.airliners.net/discussions...general_aviation/read.main/1601925

and I wasn't the only one who had the same question. Hope you find your answers.
 
GQfluffy
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 3:14 am

Quoting DfwRevolution (Reply 4):
I was under the impression it is a conservation method. Alternating the lights extend their lives compared to burning them steady.

Huh. I thought turning lights (fluorescent, halogen, zeon, incandescent) on and off were harder on the bulbs then just leaving them on...

fluffy  confused 
This isn't where I parked my car...
 
PHLBOS
Posts: 6504
Joined: Thu Apr 01, 2004 6:38 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 3:50 am

Quoting GQfluffy (Reply 7):
Huh. I thought turning lights (fluorescent, halogen, zeon, incandescent) on and off were harder on the bulbs then just leaving them on...

I believe that's true for all bulb types except incandescents.
"TransEastern! You'll feel like you've never left the ground because we treat you like dirt!" SNL Parady ad circa 1981
 
zotan
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 3:57 am

I always thought it had something to do with visibility. Its eaiser to see the blinking lights from a distance then the steady ones from what I heard.
 
pflueeb
Posts: 14
Joined: Thu Jun 23, 2005 12:16 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 9:48 am

Thanks USAirwaysbwi for the links---apparently my question has been answered! Funny though, cause you'd think that if it's good for Southwest it would be good for everyone. Increased visibility.

Later,
 
NASCARAirforce
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RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 10:25 am

Actually since most people are new, this is an often discussed topic. Surprised it has been a while since it been brought up.

I believe it is for better visibility at night.

A lot of corporate jets have this option. I have seen it a lot on Falcon 900s and 2000s, as well as some of the newer Lear jets
 
Boeing7E7
Posts: 5512
Joined: Sat Jul 31, 2004 9:35 pm

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 10:38 am

The alternating blinking lights are for bird strike protection. Nothing more, nothing less.
 
AsstChiefMark
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Joined: Thu Feb 05, 2004 2:14 pm

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:11 pm

I believe only WN's 733s and maybe 735s are equipped with this strobe-light feature

They're not STROBE lights! Strobes are filled with xenon gas and are fired using a high-voltage power supply. Landing lights are usually incandescent because they have filaments that burn in a vacuum.

Mark
Red tail...Red tail...Red tail...Red tail...Red tail...Red tail...Red tail...Red tail...Damned MSP...Red tail...Red tail
 
1MillionFlyer
Posts: 1937
Joined: Wed Sep 08, 2004 8:55 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:16 pm

DL had pulsing nav lights om their ex-Western 727's I beleive. the Green, Red and White lights all pulsed with the flip of a switch.
Golf Foxtrot you are cleared for departure
 
Fly2HMO
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Joined: Sat Jan 24, 2004 12:14 pm

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:31 pm

Most of the answers posted so far aren't accurate.

The purpose of the alternating light is to make the plane more obvious to other traffic during day (and night). It is easier to pick up flashing lights using your peripheral vision than to pick up steady lights during the day. Also, the lights burn steadily at a predetermined altitude AGL (from what I've seen, just before overflying the runway threshold, 200ft?). Aircraft with these installed usually have an option for either steady burn or pulse. These lights have been available for GA planes for quite some time.

http://www.avtek2.bizland.com/pulsar_info.htm

 twocents 
 
Tornado82
Posts: 4662
Joined: Thu May 26, 2005 10:19 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 12:40 pm

Quoting FLY2HMO (Reply 15):
It is easier to pick up flashing lights using your peripheral vision than to pick up steady lights during the day



Quoting Pflueeb (Thread starter):
You see this effect on locomotives but not airplanes

Same reason for blinking "Ditch lights" on a train. They're to be visible to the motorist at the crossings, since the train will most always be in the peripheral vision of a vehicle (or pedestrian) crossing a rail crossing. At night time though I would think the pilot wants his landing lights on solid for the visibility even before just getting to 200ft AGL. In terms of a landing plane, 200 AGL isn't much.
 
md11dude
Posts: 128
Joined: Fri May 14, 2004 8:03 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 1:30 pm

The sceamers(200s) of WestJet Also do that. Definatly different looking on approach.
CP979
 
Stealthz
Posts: 5546
Joined: Wed Feb 02, 2005 11:43 am

RE: Wig/wag Alternating Landing Lights On A WN 737?

Thu Jun 23, 2005 1:48 pm

Quote:
I was under the impression it is a conservation method. Alternating the lights extend their lives compared to burning them steady.

Not so...

Quote:
Quoting GQfluffy (Reply 7):
Huh. I thought turning lights (fluorescent, halogen, zeon, incandescent) on and off were harder on the bulbs then just leaving them on...

I believe that's true for all bulb types except incandescents.

Not so either... It is especcially true of incandescents, the constant flashing causes the filament to vibrate(constant expansion/contraction).

Pulsing the lamp does not extend it's life over a steady state, it minimises the reduction in life that would be caused by flashing it on and off.
The rise & fall in intensity is also more eyecatching than on/off, that is why the rotating beacons on emergency vehicles etc were more noticable than simple flashing lights

Visibility is greatly enhanced, from personal experience at SYD watching hundreds of QF Dash-8 approaches, those with pulselite systems stand out from the haze much earlier.
Birds eyes have a much higher "flicker rate" than humans, hence the spirals and patterns on Prop spinners and fan hubs so I would think that benefit is a minimal but welcome bonus.

Regards

Chris
If your camera sends text messages, that could explain why your photos are rubbish!