aloges
Posts: 14842
Joined: Tue Jan 17, 2006 3:38 am

Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 2:27 am

a question to all you screwdriver folks:

What lightbulbs are used in aircraft strobes, beacons and the likes?

I've tried to find info on the web, here, but alas couldn't seem to succeed. The only thing I've fond was a thread in this forum, concerning landing lights and xenon lamps used in landing lights. But those can't be used in strobes (they have to warm up), can they?

Any info will be appreciated very much!

thank you in advance,
aloges

Don't cry because it's over, smile because it happened.
 
tom775257
Posts: 141
Joined: Fri Dec 22, 2000 1:51 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 2:56 am

I believe the strobes are xenon discharge much like in a camera flash. Xenon landing lights much like in cars I assume are actually essentially metal halide high intensity discharge lamps with some xenon, mercury and some other elements….however I’m not an A/C tech.
 
dc10hound
Posts: 460
Joined: Fri Dec 15, 2000 4:18 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 3:26 am

AAL AMM 33-48-00-00:

"B. Component Description
(1)Strobe Light
The strobe light consists of a xenon flash tube mounted in a metal case, one side of which has a transparent lens.The unit also contains four energy storage capacitors which are progressively charged by pulsed DC (225V) from the control assembly unit. On application of the trigger voltage from control assembly, the capacitor rapidly discharges through the xenon tube producing a flash of white light.The capacitor peak voltage is 'set' by bleed resistors which also act as safety discharge path when power is turned off."
"Eagles soar. But weasels never get sucked into jet intakes.."
 
aa61hvy
Posts: 13021
Joined: Fri Nov 05, 1999 9:21 am

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 5:52 am

Another question that goes a long with lights. On taxi ways, and runways, how do the lights 1). Not get run over? And 2). Not ever burn out?
I know there are very elementary questions, but I completely forgot these answers. Thanks!
Go big or go home
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 5:58 am

The runway lights are level with the tarmac, the only reason you can see the light is because it is reflected through a prism, the actual light source is below the tarmac level.

Staffan
 
sccutler
Posts: 5567
Joined: Thu Jan 27, 2000 12:16 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 7:48 am

...and sometimes, the runway edge lights (which do stick up a foot or so) do get hit.

Then, it's time to call the insurance carrier!
...three miles from BRONS, clear for the ILS one five approach...
 
AJ
Posts: 2295
Joined: Wed Nov 03, 1999 3:54 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Thu May 15, 2003 9:21 am

They do go out, often en-masse. An airport vehicle will inspect the lights prior to every sundown and report any non-functioning lights for repair.
 
aloges
Posts: 14842
Joined: Tue Jan 17, 2006 3:38 am

RE: Aircraft Lightbulbs (Strobes Etc.)

Fri May 16, 2003 2:10 am

Tom775257, Dc10hound, thank you for the replies.

So the strobes don't need to warm up like xenon (head)lights because they're supplied with high voltage and heavy current. But what was used before xenon bulbs were available; I presume aircraft like the DC-8 didn't have those?
Don't cry because it's over, smile because it happened.
 
tom775257
Posts: 141
Joined: Fri Dec 22, 2000 1:51 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Fri May 16, 2003 11:05 am

This is from memory, please accept my apologies if wrong!!
There is a difference between xenon flash tubes in strobes and ‘xenon’ headlights. A xenon flash tube as found in strobes does simply have xenon gas inside as far as I know. These are old technology and the circuits are simple (I once designed a strobe circuit for one of my high school qualifications). You get a high voltage trigger leading to ionisation of the gas and a momentary current flow through the gas giving out the intense blue/white flash.
Xenon headlamps are called as such I assume for the average consumer to relate to. Maintaining a constant arc through pure xenon is difficult (I don’t know if it is possible or not), the ‘xenon’ headlamps contain xenon and a mixture of metals. The headlamps are high intensity discharge (HID) similar to high pressure sodium lamps etc…they are essentially metal halide lamps. Usually HID lamps take minutes to warm up, however in the case of ‘xenon’ headlamps sophisticated control gear gives a huge voltage to the lamp for a number of seconds decreasing voltage as the arc stabilises. The light output from ‘xenon’ headlamps if mainly from mercury vapour excitation rather than xenon gas. It is the mercury that requires the warm up period in ‘xenon’ headlights, unlike in strobes.
Hope this helps.
 
tom775257
Posts: 141
Joined: Fri Dec 22, 2000 1:51 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Fri May 16, 2003 11:21 am

OK, found you a few links:

All you could want to know about xenon strobes and circuits:
http://members.misty.com/don/donflash.html

And all you could want to know about xenon headlamps AKA short arc metal halide HID
http://members.misty.com/don/d2.html
 
shaun3000
Posts: 439
Joined: Thu Mar 14, 2002 4:10 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Fri May 16, 2003 3:56 pm

I was flying into Caddo Mills during one of my solos before I got my private. I noticed a large piece of FOD on the runway, so I taxied over to it , got out, and pickied it up. The previous landing had been pretty hard and I thought I'd knocked someting off my airplane. (A 172. Dunno what I would have knocked off!) I get to it and pick it up, and realize that it's a runway light that had been broken off and kicked several feet away from it's original spot. I was quite amazed, especially because they were set in cement. I took it over to a guy towing gliders and he thanked me.

It was kind nifty, it had a little silver tag with an FAA certification on it. Other than that, nothing special.
 
AJ
Posts: 2295
Joined: Wed Nov 03, 1999 3:54 pm

RE: Aircraft Lightbulbs (Strobes Etc.)

Fri May 16, 2003 4:29 pm

But what was used before xenon bulbs were available; I presume aircraft like the DC-8 didn't have those?

Aircraft of the vintage of the DC-8, 707, 727 and 747 originally flew with only fuselage beacons, strobes made available as a refit later on. Some airlines chose never to install strobes on these aircraft.
 
BR715-A1-30
Posts: 6525
Joined: Thu May 30, 2002 9:30 am

RE: Aircraft Lightbulbs (Strobes Etc.)

Tue May 20, 2003 10:11 am

I noticed that AirTran's DC9s have Beacons while the 717s have Xenon Strobes. Those beacons are dim compared to those strobes which will blind you if you look closely at them for too long.
Puhdiddle

Who is online

Users browsing this forum: raedgar and 12 guests