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NoobQ: Alternating Wing Lights On Landing?  
User currently offlinedanwoodman00 From United States of America, joined Feb 2011, 23 posts, RR: 0
Posted (2 years 7 months 2 weeks 4 days 20 hours ago) and read 4520 times:

i was taking my son to the museum of flight in seattle this afternoon, and we were watching the SEA traffic on final for 13L-C-R.

we saw an AS 739 coming in, with what looked like alternating-flashing lights mounted on the outermost tips of the flaps. there were several other 73x, A32x, and Dash8 planes coming in, a few of which had similar lights working, but some did not.

conditions were low-ish clouds (i'm guessing 2000ft?), only slight winds from the south, and no precip falling.

could someone tell me what the lights are, and why they'd be mounted on the flaps on a 73x? seemed like an odd place for illumination...

thanks!

- d

14 replies: All unread, jump to last
 
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 1, posted (2 years 7 months 2 weeks 4 days 19 hours ago) and read 4498 times:

Quoting danwoodman00 (Thread starter):
could someone tell me what the lights are

Landing lights.

Quoting danwoodman00 (Thread starter):
why they'd be mounted on the flaps on a 73x? seemed like an odd place for illumination...

It think it's just on the 737-300/400/500, but there's a landing light on a hinge in the flap fairing. It drops down into the airstream when it's turned on. Shown in the retracted position:
http://www.b737.org.uk/images/flap_farings.jpg

On the 737NG those lights were moved to the belly. You can see them sticking out below where the leading edge meets the fuselage:


Tom.


User currently offlineflybaurlax From United States of America, joined Oct 2008, 638 posts, RR: 0
Reply 2, posted (2 years 7 months 2 weeks 4 days 17 hours ago) and read 4446 times:

It's called pulse lighting. It makes it easier for the aircraft to be identified by other aircraft because the flashing catches your eye. I was also told it has a psychological effect on birds, and that they try to fly away from it. I'm not sure if the latter is correct.

http://www.youtube.com/watch?v=Yfv4W0rmNus

Alaska started putting them in a little over a year ago. It's a customer option, and the pilot can select between steady and pulse.



Boilerup! Go Purdue!
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 3, posted (2 years 7 months 2 weeks 4 days 13 hours ago) and read 4405 times:

Quoting tdscanuck (Reply 1):
Quoting danwoodman00 (Thread starter):
why they'd be mounted on the flaps on a 73x? seemed like an odd place for illumination...

It think it's just on the 737-300/400/500, but there's a landing light on a hinge in the flap fairing. It drops down into the airstream when it's turned on. Shown in the retracted position:

The DC-9, and I think also the MD-8x, has the landing lights in a flap track fairing. They also drop down when turned on.

There's a noticeable change in vibration when they come out.

[Edited 2011-12-15 04:33:54]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinedanwoodman00 From United States of America, joined Feb 2011, 23 posts, RR: 0
Reply 4, posted (2 years 7 months 2 weeks 4 days 9 hours ago) and read 4334 times:

thanks for the info and explanation -- the photos and youtube clip are exactly what we saw. much appreciated.

@flybaurlax -- so you're saying they're like "deer horns" for planes!?   


User currently offlineSSTeve From United States of America, joined Dec 2011, 695 posts, RR: 1
Reply 5, posted (2 years 7 months 2 weeks 3 days 20 hours ago) and read 4150 times:

You see them a lot with the seaplane traffic on Lake Union as well. Very eye-catching way to warn boaters they're on the runway.

User currently offlineLonghornmaniac From United States of America, joined Jun 2005, 3278 posts, RR: 45
Reply 6, posted (2 years 7 months 2 weeks 3 days 19 hours ago) and read 4132 times:

Quoting Starlionblue (Reply 3):
I think also the MD-8x

The MD-80 landing lights are at the wingtips, but it's a similar drop down mechanism.

Cheers,
Cameron


User currently offlinerendezvous From New Zealand, joined May 2001, 515 posts, RR: 0
Reply 7, posted (2 years 7 months 1 week 5 days 18 hours ago) and read 3679 times:

They certainly make the planes easier to spot when you're trying to find them.
Is the alternating light distracting during landing at night?


User currently offlineShamrock137 From United States of America, joined Jul 2005, 141 posts, RR: 0
Reply 8, posted (2 years 7 months 1 week 5 days 4 hours ago) and read 3622 times:

Quoting rendezvous (Reply 7):
Is the alternating light distracting during landing at night?

For most operators, procedure is to turn the lights from flash to steady at some point before landing. Some do it when passing through a set altitude, or when the gear is extended. During the day however, the lights can be left in flash right through the landing.



Time to spare? Go by air!
User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 9, posted (2 years 7 months 1 week 4 days 23 hours ago) and read 3580 times:

Quoting Longhornmaniac (Reply 6):

They're fun to watch being extended (on final or just before takeoff) if they're illuminated before they're extended when it's dark out with sufficient humidity...the more humidity the better, of course. Quite dramatic to watch the beam shift from downward-illuminating (stowed position) to forward-illuminating.

The DC-9 family all has them, though I'm not sure about the 717.



Jack @ AUS
User currently offlineN243NW From United States of America, joined Jul 2003, 1628 posts, RR: 20
Reply 10, posted (2 years 7 months 1 week 4 days 22 hours ago) and read 3562 times:

Quoting Longhornmaniac (Reply 6):
The MD-80 landing lights are at the wingtips, but it's a similar drop down mechanism.

Yep. They do cause noticeable vibration, which is why many pilots turn them off and retract them just after the gear comes up. I loved watching the late evening departures from DFW from my bedroom window and seeing the lights go out as the aircraft passed overhead.



B-52s don't take off. They scare the ground away.
User currently offlinewn700driver From , joined Dec 1969, posts, RR:
Reply 11, posted (2 years 7 months 1 week 4 days 22 hours ago) and read 3560 times:

Quoting tdscanuck (Reply 1):

It think it's just on the 737-300/400/500, but there's a landing light on a hinge in the flap fairing. It drops down into the airstream when it's turned on. Shown in the retracted position:

Quite true. Back when I was still working on 73s, there was a persistant rumor that the NGs were eventually going back to that configuration on the basis that the inboard (and lower positioned) landing lights were more subject to rock and runway debris damage. Did you ever hear anything about that?

Quoting Western727 (Reply 9):
They're fun to watch being extended (on final or just before takeoff) if they're illuminated before they're extended when it's dark out with sufficient humidity...the more humidity the better, of course. Quite dramatic to watch the beam shift from downward-illuminating (stowed position) to forward-illuminating.

When I was in mx, we'd do nightly light checks (among many other things) on those. When you turn the lights on, yes they do light up, then position.

I remember one night a few years back when I set the lights and from outside I heard whistling from near the lights. I knew that the whistling was the tune from some movie familiar to me but I couldn't quite place it until I heard the guy shout out "Tanis! I knew it!" when the lights stopped moving.

Man, hard to believe that Raiders of the lost Ark is almost 30years old now, lol...


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 12, posted (2 years 7 months 1 week 4 days 6 hours ago) and read 3482 times:

Quoting wn700driver (Reply 11):
there was a persistant rumor that the NGs were eventually going back to that configuration on the basis that the inboard (and lower positioned) landing lights were more subject to rock and runway debris damage. Did you ever hear anything about that?

I heard the same rumours but I think it never got past the concept stage...it's been rumour for so long that, by now, I assume it's just not going to happen. They might have done something to the lenses to improve FOD resistance (similar changes were made to the APU drain mast).

Tom.


User currently offlineyeelep From United States of America, joined Apr 2011, 649 posts, RR: 0
Reply 13, posted (2 years 7 months 1 week 4 days 5 hours ago) and read 3457 times:

Never heard that rumour, but have seen allot of cracked lenses. Honeywell does have a improved lens as of October 2009. Its identified by a mark approximately ½ inch in diameter, located in the center of the inside surface of the lens.

User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 14, posted (2 years 6 months 4 weeks 17 hours ago) and read 2942 times:

Any study is Pulse lighting increases the life of the Landing light as the use is 50% of normal due to the flashing.....


Think of the brighter side!
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