Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
A320ajm
Topic Author
Posts: 587
Joined: Sat May 20, 2006 11:57 pm

Wheel Well Fire Extinguishers

Wed Aug 12, 2015 7:08 pm

Hi all,

Being a bit of an aircraft geek, a colleague and friend asked me whether I had seen the following incident:

http://avherald.com/h?article=48a77cf2&opt=0

He had never heard of this, so I was talking about how hot wheels can get etc. He then asked: "Do aircraft have "Wheel Well Fire Extinguishers like on the engines? " This totally stumped me. Does this exist on any aircraft? If so, why not?

Thanks in advance for all your help!
A320ajm
If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Wheel Well Fire Extinguishers

Wed Aug 12, 2015 7:28 pm

As far as Boeing airplanes are concerned they all have main gear (not nose gear) fire detection systems but no fire extinguishing system. The second step on the FIRE WHEEL WELL checklist is to put the landing gear down, which is expected to put the fire out.
 
User avatar
fr8mech
Posts: 8026
Joined: Mon Sep 26, 2005 9:00 am

RE: Wheel Well Fire Extinguishers

Wed Aug 12, 2015 7:30 pm

I've never seen a wheel well fire extinguisher as onboard equipment. As I recall, the procedure for a wheel well fire is to slow the aircraft, deploy the landing gear and land ASAP.
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
A320ajm
Topic Author
Posts: 587
Joined: Sat May 20, 2006 11:57 pm

RE: Wheel Well Fire Extinguishers

Wed Aug 12, 2015 8:02 pm

Quoting 7BOEING7 (Reply 1):
As far as Boeing airplanes are concerned they all have main gear (not nose gear) fire detection systems but no fire extinguishing system. The second step on the FIRE WHEEL WELL checklist is to put the landing gear down, which is expected to put the fire out.
Quoting fr8mech (Reply 2):

I've never seen a wheel well fire extinguisher as onboard equipment. As I recall, the procedure for a wheel well fire is to slow the aircraft, deploy the landing gear and land ASAP.

Thanks for your answers. Seems a bit strange to me there is no extinguisher system. However, I guess if you're high enough the lack of oxygen will help in assisting the fire to extinguish.

A320ajm
If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
 
User avatar
Stitch
Posts: 27092
Joined: Wed Jul 06, 2005 4:26 am

RE: Wheel Well Fire Extinguishers

Wed Aug 12, 2015 8:56 pm

Quoting a320ajm (Reply 3):
Seems a bit strange to me there is no extinguisher system.

I am guessing worries about extinguisher contaminating the brakes or the hydraulic systems.
 
User avatar
fr8mech
Posts: 8026
Joined: Mon Sep 26, 2005 9:00 am

RE: Wheel Well Fire Extinguishers

Wed Aug 12, 2015 9:12 pm

Quoting Stitch (Reply 4):
I am guessing worries about extinguisher contaminating the brakes or the hydraulic systems.

Not at all.

A wheel well fire indication is typically an overheated brake that has begun to burn or has caused material in the wheel well to burn. When the temperature of the brake/wheel assembly mass reaches a preset temperature, the wheel's fusible plug vents. This vents nitrogen into the space, hopefully smothering the fire.

But, as stated, the primary fire fighting/cooling method is to deploy the gear, which should blow out the fire.
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
JohnM
Posts: 395
Joined: Sat Feb 24, 2001 12:35 pm

RE: Wheel Well Fire Extinguishers

Thu Aug 13, 2015 12:13 am

Not a civil airplane, but the C-5 does. A C-5 was lost early in the program due to a wheel well fire which I think was before the fire suppression system (FSS) was installed. There are wheel well fire loops (in many other areas as well), and a liquid nitrogen system that will discharge into the wheel well. The end result is oxygen is displaced, no fire. A discharge of nitrogen in the wheel well would not be fun while doing maintenance however... FSS is a good when on fire of course, but is a total pain to fix and makes other tasks more time consuming and involved.
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Wheel Well Fire Extinguishers

Thu Aug 13, 2015 1:01 am

Quoting a320ajm (Thread starter):
Does this exist on any aircraft? If so, why not?

The point of diminishing returns...unlike the C-5 Galaxy, exceedingly few civil aircraft have been lost to wheel well fires. One of the design goals of an aircraft is to be as light as possible, so that the thing flies and makes money for its operator. The more unnecessary systems you add to a plane, the heaver it becomes...   
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Wheel Well Fire Extinguishers

Thu Aug 13, 2015 4:11 am

Quoting KELPkid (Reply 7):
The point of diminishing returns...unlike the C-5 Galaxy, exceedingly few civil aircraft have been lost to wheel well fires.

Mexicana 940 (727) was lost but that was due to maintenance servicing a tire with compressed air instead of nitrogen causing the tire to explode and sever fuel/hydraulic lines leading to an uncontrollable fire. I'm not sure a fire suppression system would have been any use in this case.

http://aviation-safety.net/database/record.php?id=19860331-1&lang=en

Similarly a Swissair Caravelle took off with overheated brakes (due to excessive use during extended taxi) which caused an inflight fire shortly after takeoff (we have procedures in place and brake overheat warning systems now) and a Nation Air DC-8 took off with underinflated tires (cockpit tire pressure indications are now available on most new airplanes these days) and crashed shortly after takeoff (if the takeoff had bee aborted or the gear left extended after takeoff the crash wouldn't have occurred).


http://aviation-safety.net/database/record.php?id=19630904-0 Swissair

http://aviation-safety.net/database/record.php?id=19910711-0 Nation Air
 
Max Q
Posts: 8286
Joined: Wed May 09, 2001 12:40 pm

RE: Wheel Well Fire Extinguishers

Thu Aug 13, 2015 5:19 am

Not really what you're asking but the B727 APU is mounted transversely across the keel beam and occupies
part of the left and right wheel wells.


It has a fire extinguisher of course.
The best contribution to safety is a competent Pilot.


GGg
 
User avatar
fr8mech
Posts: 8026
Joined: Mon Sep 26, 2005 9:00 am

RE: Wheel Well Fire Extinguishers

Thu Aug 13, 2015 6:05 am

Quoting Max Q (Reply 9):
It has a fire extinguisher of course.

As I recall, that fire extinguisher dumps into the cowling, not the wheel well area.
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Thu Aug 27, 2015 11:09 pm

Quoting 7BOEING7 (Reply 1):
As far as Boeing airplanes are concerned they all have main gear (not nose gear) fire detection systems but no fire extinguishing system.

I'm not trying to nitpick, but I just can't recall...did the 727's with nosewheel brakes have fire detection in the NLG well? For some reason I thought I remembered that, but it has been a LONG time.
 
User avatar
fr8mech
Posts: 8026
Joined: Mon Sep 26, 2005 9:00 am

RE: Wheel Well Fire Extinguishers

Fri Aug 28, 2015 12:45 am

Quoting PGNCS (Reply 11):
I'm not trying to nitpick, but I just can't recall...did the 727's with nosewheel brakes have fire detection in the NLG well? For some reason I thought I remembered that, but it has been a LONG time.

It's been about 30 years since I've seen one of those, but I would think that it would be required. How else would the flight crew know they had overheated brakes?
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
User avatar
DL_Mech
Posts: 2461
Joined: Fri Feb 18, 2000 7:48 am

RE: Wheel Well Fire Extinguishers

Fri Aug 28, 2015 2:06 am

Quoting PGNCS (Reply 11):
did the 727's with nosewheel brakes have fire detection in the NLG well?


I found a 1981 727 training manual that shows one fire loop in the nose wheel well and four in the main gear wells.

It shows the nose loop as a 255 degree F loop and the mains as 400 degree F all wired in series.
This plane is built to withstand anything... except a bad pilot.
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 1:12 am

Quoting DL_Mech (Reply 13):
Quoting PGNCS (Reply 11):did the 727's with nosewheel brakes have fire detection in the NLG well?

I found a 1981 727 training manual that shows one fire loop in the nose wheel well and four in the main gear wells.

It shows the nose loop as a 255 degree F loop and the mains as 400 degree F all wired in series.

Thanks! I didn't think I was making that up out of thin air but, man, it's been a long time! I appreciate the info from you and fr8mech!
 
User avatar
DL_Mech
Posts: 2461
Joined: Fri Feb 18, 2000 7:48 am

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 2:08 am

Quoting PGNCS (Reply 14):
I didn't think I was making that up out of thin air but, man, it's been a long time!

Tell me about it, I can't believe the 727s (and L-1011s) have been gone for almost 15 years.
This plane is built to withstand anything... except a bad pilot.
 
26point2
Posts: 1094
Joined: Wed Mar 03, 2010 6:01 am

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 3:13 am

Quoting a320ajm (Thread starter):

Jet engines (fire is good) do not have fire extinguishers...modern jet engines at least. Gear box and acessories do have them however.
 
mmo
Posts: 2054
Joined: Thu Apr 18, 2013 3:04 pm

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 5:27 am

Quoting 26point2 (Reply 16):
Jet engines (fire is good) do not have fire extinguishers...modern jet engines at least. Gear box and acessories do have them however.

Care to share an example, as I know of no engine that has the system you are describing. Certainly there is no fire protection for gear boxes.
If we weren't all crazy we'd all go insane!
 
User avatar
fr8mech
Posts: 8026
Joined: Mon Sep 26, 2005 9:00 am

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 6:52 am

Quoting mmo (Reply 17):
Care to share an example, as I know of no engine that has the system you are describing. Certainly there is no fire protection for gear boxes.

I suspect he means: under the cowling.

The fire detection system covers all the areas under the cowling. Same with the fire protection/extinguishing system, all areas under the cowling are covered. The internal engine is not covered/protected.

The only example I can recall where the internal engine is monitored for fire was on the JT9. The #3 Bearing...the hottest area in the lubrication system...breather went through a fusible tube, overboard. If the temperature of the breather air exceeded the melt point of the tube, it would melt and vent that hot breather air under the cowl. The fire loop would pick up the elevated temperature. The flight crew goes through the process, that eventually leads to the flight crew shutting down the engine and, hopefully, extinguishing the fire.
When seconds count, the police are minutes away.
It’s hard to win an argument with a smart person, but it’s damn near impossible to win an argument with a stupid person. ~B. Murray
Ego Bibere Capulus, Ut Aliis Sit Vivere
 
User avatar
HAWK21M
Posts: 30067
Joined: Fri Jan 05, 2001 10:05 pm

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 9:00 am

Detectors yes through fire loops to provide flight deck/cockpit indications....normally the extension of the LG is called for during such occurrences.
I may not win often, but I damn well never lose!!! ;)
 
mmo
Posts: 2054
Joined: Thu Apr 18, 2013 3:04 pm

RE: Wheel Well Fire Extinguishers

Sat Aug 29, 2015 7:59 pm

Quoting fr8mech (Reply 18):
I suspect he means: under the cowling.

The fire detection system covers all the areas under the cowling. Same with the fire protection/extinguishing system, all areas under the cowling are covered. The internal engine is not covered/protected.

Well, the poster is a native English speaker, so I can only go by what he wrote. And I learned a loooong time ago, not to assume anything about what is written.

It did get my attention, because several years ago, I had an engine fire, non-extinguishable, that required an immediate return after takeoff. The culprit was the accessory drive which had run dry. The casing is constructed out of magnesium and it caught on fire. So, I know for a fact, there is no agent present in that area! That was on a JT9-7Q.
If we weren't all crazy we'd all go insane!
 
Max Q
Posts: 8286
Joined: Wed May 09, 2001 12:40 pm

RE: Wheel Well Fire Extinguishers

Sun Aug 30, 2015 6:48 am

Quoting PGNCS (Reply 11):
I'm not trying to nitpick, but I just can't recall...did the 727's with nosewheel brakes have fire detection in the NLG well? For some reason I thought I remembered that, but it has been a LONG time.

Five years on that aircraft in two different seats and I never heard of a nose landing gear wheel fire detector.
The best contribution to safety is a competent Pilot.


GGg
 
mmo
Posts: 2054
Joined: Thu Apr 18, 2013 3:04 pm

RE: Wheel Well Fire Extinguishers

Sun Aug 30, 2015 8:14 am

Quoting Max Q (Reply 21):
Five years on that aircraft in two different seats and I never heard of a nose landing gear wheel fire detector.

When the nose gear brake system was removed, part of the task was to remove the nose gear wheel well overheat loop.
If we weren't all crazy we'd all go insane!
 
Max Q
Posts: 8286
Joined: Wed May 09, 2001 12:40 pm

RE: Wheel Well Fire Extinguishers

Sun Aug 30, 2015 9:09 am

Quoting mmo (Reply 22):
When the nose gear brake system was removed, part of the task was to remove the nose gear wheel well overheat loop.

Ok, makes sense, learned something else about my favourite jet.
The best contribution to safety is a competent Pilot.


GGg
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Mon Aug 31, 2015 1:45 am

Quoting Max Q (Reply 21):

Quoting PGNCS (Reply 11):
I'm not trying to nitpick, but I just can't recall...did the 727's with nosewheel brakes have fire detection in the NLG well? For some reason I thought I remembered that, but it has been a LONG time.

Five years on that aircraft in two different seats and I never heard of a nose landing gear wheel fire detector.

OK...I'm trying not to get a big head here, but I can't believe I taught you of all people something about the 727!

ANYTHING is possible!  
 
Max Q
Posts: 8286
Joined: Wed May 09, 2001 12:40 pm

RE: Wheel Well Fire Extinguishers

Mon Aug 31, 2015 5:47 am

Quoting PGNCS (Reply 24):
OK...I'm trying not to get a big head here, but I can't believe I taught you of all people something about the 727!

ANYTHING is possible!

You did so let me ask you a question, how many pieces of wood are there in the 727 ?!
The best contribution to safety is a competent Pilot.


GGg
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Mon Aug 31, 2015 6:54 pm

Quoting Max Q (Reply 25):
Quoting PGNCS (Reply 24):OK...I'm trying not to get a big head here, but I can't believe I taught you of all people something about the 727!

ANYTHING is possible!
You did so let me ask you a question, how many pieces of wood are there in the 727 ?!

I believe the answer is six if I recall correctly, but I'm open to correction from a 727 guru of your stature!  
 
User avatar
tb727
Posts: 2206
Joined: Thu Jun 30, 2005 1:40 pm

RE: Wheel Well Fire Extinguishers

Mon Aug 31, 2015 11:19 pm

Quoting PGNCS (Reply 26):
I believe the answer is six if I recall correctly, but I'm open to correction from a 727 guru of your stature!

Also what's the only letter of the alphabet not on any of the panels?
Too lazy to work, too scared to steal!
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Tue Sep 01, 2015 12:48 am

Quoting tb727 (Reply 27):
Quoting PGNCS (Reply 26):I believe the answer is six if I recall correctly, but I'm open to correction from a 727 guru of your stature!
Also what's the only letter of the alphabet not on any of the panels?

Well first off I am NOT the 727 expert...is 6 the right answer for the wood question?

As for letters on the panels, I have no idea, so I will just take the seemingly obvious route and say Z, though I'm doubting it would be that easy...(I'm debating if something is labeled HZ vs. CPS, but not quite curious enough to look this up myself!)
 
User avatar
tb727
Posts: 2206
Joined: Thu Jun 30, 2005 1:40 pm

RE: Wheel Well Fire Extinguishers

Tue Sep 01, 2015 2:31 am

Quoting PGNCS (Reply 28):
Well first off I am NOT the 727 expert...is 6 the right answer for the wood question?

I've always heard 6 too. FE desktop, wood blocks in the fuel dump panel, block of wood on the left side of the FE panel, nosewheel doors which brings me back to the wheel well fire extinguishers. I do remember looking up there and seeing remnants of a loop on a freighter once, possibly even a loop because I remember asking the question about them. I'll dig through my pics to see if I ever took any up in there.

The letter is J...I think, lol. That was more directed at Max Q, I'm losing it!

I've heard from some of the more seasoned FE's that a good way to get a wheel well fire warning was to forget to shutdown the APU for flight, not too long after gear retraction I guess you get it. I'm pretty sure it is supposed to shut down automatically but it may be the quick manner in which it does that will still get a lot of heat in there.
Too lazy to work, too scared to steal!
 
Max Q
Posts: 8286
Joined: Wed May 09, 2001 12:40 pm

RE: Wheel Well Fire Extinguishers

Tue Sep 01, 2015 2:11 pm

Quoting tb727 (Reply 29):
I've always heard 6 too. FE desktop, wood blocks in the fuel dump panel, block of wood on the left side of the FE panel, nosewheel doors

That's one more than I knew of, outstanding !

Quoting tb727 (Reply 29):
I've heard from some of the more seasoned FE's that a good way to get a wheel well fire warning was to forget to shutdown the APU for flight, not too long after gear retraction I guess you get it. I'm pretty sure it is supposed to shut down automatically but it may be the quick manner in which it does that will still get a lot of heat in there.

Well, I did that once (reached back and shut it off without anyone noticing) and didn't get a fire warning. It seemed to be running quite happily though and I think it was over 10k before I noticed it so I don't think it would shut down automatically.


Of course you couldn't (theoretically) start it once airborne but it would keep running if you forgot.


Just as an aside I had a very occurrence on a B727 in cruise while I was an FE.
I noticed a flicker of movement to my right and to my amazement saw the APU starting up by itself, I pointed it out to the Captain and shut it down using the fire handle.


Maintenance couldn't explain it but I had a few odd happenings on that aircraft, of course our maintenance was abysmal in those days.
The best contribution to safety is a competent Pilot.


GGg
 
User avatar
tb727
Posts: 2206
Joined: Thu Jun 30, 2005 1:40 pm

RE: Wheel Well Fire Extinguishers

Tue Sep 01, 2015 3:31 pm

Quoting Max Q (Reply 30):
Well, I did that once (reached back and shut it off without anyone noticing) and didn't get a fire warning. It seemed to be running quite happily though and I think it was over 10k before I noticed it so I don't think it would shut down automatically.

I'm not surprised, I am pretty sure nothing is really "automatic" on that plane!
Too lazy to work, too scared to steal!
 
PGNCS
Posts: 2260
Joined: Sun Apr 15, 2007 5:07 am

RE: Wheel Well Fire Extinguishers

Tue Sep 01, 2015 8:14 pm

Quoting tb727 (Reply 29):
That was more directed at Max Q, I'm losing it!

Well I'm glad, because I am totally outclassed in 727 general knowledge by you two!

I was thinking of the JATO-equipped 727's of course...yeah, that's it...that's the reason I didn't guess "J"!  

Who is online

Users browsing this forum: afterburner, milhaus, Starlionblue and 30 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos