highflyer9790
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773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 7:12 am


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any idea why AC's new 773 would have one of its runway turn off lights burnt out already after only a few days into her new life? am i missing something?
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Tristarsteve
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 7:26 am

They are taxi lights, and theyseem to crack all the time.
I assume its stone damage, but the lenses are cracked, and those lights need changing 20 x more often than any other exterior light.
 
flipdewaf
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 7:42 am

Interesting, although components are more likely to be unreliable toward the start of their life. I suppose thats why they dont just have the one.

Fred
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EMBQA
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 10:35 am

Quoting HighFlyer9790 (Thread starter):
any idea why AC's new 773 would have one of its runway turn off lights burnt out already after only a few days into her new life? am i missing something?

Am I missing something...?? I see all three lights working..........and what is a 'runway turn off light'...?? I'm thinking like other bigger aircraft I've seen the upper two are landing lights, the lower light is the taxi light. Also, looking at other photos in the data base I several other a/c with the same configuration, so it may be a switch controlled deal.

[Edited 2007-04-19 03:50:36]
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boeingfixer
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 1:48 pm

AFAIK, the 773 has 2 nose gear taxi lights and 2 nose gear landing lights. One of them appears to be burnt out.... no big deal as it has nothing to do with the aircraft in general. Landing and taxi lights burn out all the time so this is a non-issue. Light bulb replacement is probably one of the highest maintenance discrepancy entries in the business.

Cheers,

John
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HAWK21M
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 3:12 pm

Looks like one Taxi light is u/s.
Reason could be burnt filament/CB popped out or FOD.

Quoting EMBQA (Reply 3):
what is a 'runway turn off light'

Runway Turn off light is angled from the Aircraft centreline & illuminates the area just forward & side.It covers the direction the Aircraft will turn into.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
BAE146QT
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 4:23 pm

Quoting Flipewaf:
Interesting, although components are more likely to be unreliable toward the start of their life.

Agreed. We call that the "bathtub curve". Imagine a graph where the X axis is time and the Y axis is probability of failure.

Very new and very old components are statisitcally more likely to go pop. So the graph looks like a cross-section of a bathtub.
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flipdewaf
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 8:05 pm

Quoting BAe146QT (Reply 6):
Very new and very old components are statisitcally more likely to go pop.

go pop! i like that way of putting it, il use it more in future. we use the bath tub model at uni, i hate doing reliability though its such a faf on.

Fred
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BAE146QT
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Thu Apr 19, 2007 8:20 pm

Ah - looks like I was giving egg-sucking instructions then  Wink To be honest we only use it in the loosest sense - it's not like we're worried about component reliability enough to have real metrics. Not in my department at least. The support guys probably take a different view - especially when they've swapped out a Gigabit NIC for the 40,000th time.

Quoting Flipdewaf:
go pop! i like that way of putting it,

Surprised you've not heard that before - there's loads of variations.
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GlobalATL
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Fri Apr 20, 2007 9:33 am

Quoting HighFlyer9790 (Thread starter):
one of its runway turn off lights burnt out already

I noticed too. Its a brand new plane! The bulb must be second-hand!  

[Edited 2007-04-20 02:56:45]

[Edited 2007-04-20 02:57:26]
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flyabunch
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Fri Apr 20, 2007 1:22 pm

Quoting GlobalATL (Reply 9):
I noticed too. Its a brand new plane! The bulb must be second-hand!

Maybe not second-hand, but certainly from the low bidder for the supply item!

Mike
 
metroliner
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Fri Apr 20, 2007 9:27 pm

one thing - do the pilots have any way of seeing from the cockpit (in the form of a master caution light or something) that one of the bulbs has blown out? not particularly serious, in the case of a taxi light, but if a landing light blows i'm sure it would be nice to know about it!

toni
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flipdewaf
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Fri Apr 20, 2007 9:37 pm

Quoting Flyabunch (Reply 10):
Quoting GlobalATL (Reply 9):
I noticed too. Its a brand new plane! The bulb must be second-hand!

Maybe not second-hand, but certainly from the low bidder for the supply item!

Mike

It'll be the same as the other bulbs on T7's just that components are less reliable when new, a component is much more likely to fail in the first week than after 6 years.

Fred
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Tristarsteve
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Fri Apr 20, 2007 11:15 pm

Actually the large lamps on aircraft are all the same.
Landing lights Q4559X are fitted to B737 B757 B767 B777 and A320 and more.
So are the taxi light in question Q4554 is the same pt nbr as the taxi light on the A320.
Most of these lamps come from GE.

Quoting Metroliner (Reply 11):
do the pilots have any way of seeing from the cockpit (in the form of a master caution light or something) that one of the bulbs has blown out? not particularly serious,

No. We change many more lamps in the winter, when the pilots can see they are not working, than in the summer, when they can't!
 
777wt
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Sat Apr 21, 2007 4:50 am

Quoting TristarSteve (Reply 13):
Landing lights Q4559X are fitted to B737 B757 B767 B777 and A320 and more.

Even that's the same part # for a ERJ-145 nose landing light.
 
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HAWK21M
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Sat Apr 21, 2007 3:27 pm

Quoting TristarSteve (Reply 13):
No. We change many more lamps in the winter, when the pilots can see they are not working, than in the summer, when they can't!

What about night ops.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Tristarsteve
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Sat Apr 21, 2007 6:46 pm

Quoting HAWK21M (Reply 15):
What about night ops.

In Sweden it doesn't get dark until midnight in the summer. We don't have any night ops!

On the single aisle Airbus, there are four lights on the nose leg. A taxi light, a Take-off light, and two runway turnoff lights.
The Landing lights are in the wingroot. The landing lights are angled down. When the aircraft is parked, they shine on the ground just forward of the nose. I had a pilot write them up recently. "Landing lights point downwards" Answer was. " They are meant to, they are landing lights!" The take off light points forwards for take off.
On Boeings, the nose leg landing lights point more forwards so are used for take off as well. The runway turn off lights on Boeings are fitted in the wing root.

Another strange thing about landing/taxi lights is the voltage. Look in the wiring manual, they are strange. You often get 28vAC lights wired up to 115vAC supply through a transformer. I wonder why? Why not have 115vAC lights?
 
metroliner
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Sat Apr 21, 2007 9:50 pm

Quoting TristarSteve (Reply 13):
No. We change many more lamps in the winter, when the pilots can see they are not working, than in the summer, when they can't!

thank you. some very interesting info there!
Set the controls for the heart of the Sun
 
brettbrett21
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 5:44 am

Quoting TristarSteve (Reply 16):
The Landing lights are in the wingroot. The landing lights are angled down. When the aircraft is parked, they shine on the ground just forward of the nose. I had a pilot write them up recently. "Landing lights point downwards" Answer was. " They are meant to, they are landing lights!"

You have got to be joking!
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kaddyuk
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 7:48 am

Quoting HighFlyer9790 (Thread starter):
any idea why AC's new 773 would have one of its runway turn off lights burnt out already after only a few days into her new life? am i missing something?

This aircraft has been in production for months... including i dont know how many hours flight testing & route proving... Just because its only been in active service for 3 days doesnt mean the aircraft popped out of a mystical vortex with every component being brand new and produced on exactly the same date...
Whoever said "laughter is the best medicine" never had Gonorrhea
 
Slovacek747
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 9:31 am

Off topic but, how does AC like their 777 so far? Are the economics/fuel burn what they thought they would be?

Slovacek747
 
flipdewaf
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 11:25 am

Quoting Slovacek747 (Reply 20):

adding to this, do planes have run in times like cars do? will they be running at maximim efficiency yet?


Fred
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schooner
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 9:46 pm

Quoting HighFlyer9790 (Thread starter):
They are taxi lights, and theyseem to crack all the time.
I assume its stone damage, but the lenses are cracked, and those lights need changing 20 x more often than any other exterior light.

or perhaps they havent turned on one of the turn-off lights. In the 757 at least they are independantly switchable.

Cheers.
Untouched and Alive
 
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HAWK21M
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Mon Apr 23, 2007 11:16 pm

Quoting TristarSteve (Reply 16):
The landing lights are angled down



Quoting TristarSteve (Reply 16):
Landing lights point downwards

On Single Aisle ie A320 Family.Is this on any other types.Found it odd that theres seperate Take off & Landing lights.

Quoting TristarSteve (Reply 16):
You often get 28vAC lights wired up to 115vAC supply through a transformer. I wonder why? Why not have 115vAC lights

Isn't it because the Reley operation with 28vac is less & safer Weight & consumption wise.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
tom775257
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 12:48 am

Having flown two new jets, one 1 week old, and one 3 weeks old; these had the most deferred defects of any aircraft in the fleet at the time.
 
Tristarsteve
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 3:18 am

Quoting Schooner (Reply 22):
Quoting HighFlyer9790 (Thread starter):
They are taxi lights, and theyseem to crack all the time.
I assume its stone damage, but the lenses are cracked, and those lights need changing 20 x more often than any other exterior light.

or perhaps they havent turned on one of the turn-off lights. In the 757 at least they are independantly switchable.

Read what you quote. They are taxi lights on a B777, one switch. On a A320 they are turn off lights, one switch.
On B777 the turn off lights are in the wing root.
 
dl757md
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 5:21 am

There are many possibilities for the INOP taxi light in this photo. It could be as has already been said FOD damage that cracked the lens and led to premature filament burnout. It could be a defective lamp. It's could be a factory induced wiring problem leading to either a short or an open. It could be that maintenance while performing an external light check left the CB for the left taxi light out and the flight crew missed it. We pull breakers for taxi lights and nose landing lights all the time to easily check if they're working when you don't have someone on the ground to make sure both lights are working. You have to do this because you only have 1 switch for both lights but each light has its own CB.

In any case it's no big deal, even on a 3 day old airplane.

DL757Md
757 Most beautiful airliner in the sky!
 
JohnM
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 8:56 am

The bulbs have a short life due to overheating also. If they are left on a bit too long without airflow, they get very hot, and no air to carry the heat away. I haven't worked this type of airplane, but on "my" plane, the crew misses a step, or chit chats while the taxi and/or landing lights are on, it can fry them. 500 or 1000 watts is LOTS of heat. I think taxi is enough airflow, but sitting still is a problem if done for too long. Helicopters have started brush fires with landing lights left on after a field landing.
 
schooner
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 4:21 pm

Quoting TristarSteve (Reply 25):
Read what you quote.

Duuh, sorry mate, had just woken up after getting back from a night AYT, not entirely with it there!

Cheers.
Untouched and Alive
 
b78710
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Tue Apr 24, 2007 7:16 pm

also when you do up the locking rings around lamps too tight, combined with being heated up and cooled to very low temps it can cause them to crack or shatter. the ring only needs to be done up enough to hold the lamp in place! happens a lot to our airbus landing lights!
 
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HAWK21M
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RE: 773 Bulb Burn Out After Only 3 Days?!?

Wed Apr 25, 2007 4:22 pm

Quoting B78710 (Reply 29):
the ring only needs to be done up enough to hold the lamp in place!

Thermal Expansion.

On the 737NGs the Landing lights below the Fusdelage are suseptible to FOD & water slosh.

regds
MEL
I may not win often, but I damn well never lose!!! ;)

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