Help! Boeing Gear Bay Fire Info Needed

[Aerobobby]

Hi,

I need to know the answer to this ASAP.

I am under the understanding that when Boeing have a gear bay fire, they are supposed to extend the gear to extinguish it.

Apparantly, there was an incident where extending the gear did not extinguish the fire?

Is this true, and if so, do any of you guys have the details of the incident?

Thanks a million!

[Flaperon777]

Nope,havent heard of this one.Unless the aircrart was on ground when it happened!!

[MrBernoulli]

And if extending the gear didn't extinguish the fire, what is your (rushed) point? Emergency procedures are attempts, using best practise as known at the time, to contain a problem. There are no guarantees that a procedure will work. You hope it will work, some may even expect it to work. But it is not guaranteed to work.

[Starbear]

I am not familiar with the actual incident but something which adds to the likliehood of it being true:

Given that most wheel well "fires" were probably heat from overheated brakes without flames and "fire" indications were removed as soon as gear was extended, the wheel well fire drill on some Boeings, used to call for the gear to be retracted, after a suitable cooling period of time following extension.

At some point in the fairly distant past, that drill changed to leaving the gear extended and land asap. Gear may still be retracted after the cooling period, if performance requires it.

It is not uncommon for specific incidents to be the cause for such changes in drills.

[Spooky 2]

To my knowledge there is no procedure that "recommends" a gear retraction after a gear fire warning. There is language that says if the gear has to be retracted, wait 20 minutes before doing so. Supposedly hot brakes alone will not trigger a wheel well fire alarm

Mexicana lost a B727 many years ago do to a brake/wheel fire. Don't recall the details but I'm sure once could do a little research and find the accident report.

[hetfield]

To frighten all the Boeing guys, there is NO Wheel Well Fire warning sys on AB.

AND....

the brake temp ind sys may be inop.....as well as tyre press sys, if installed.......

[lomapaseo]

Hi,

I need to know the answer to this ASAP.

I am under the understanding that when Boeing have a gear bay fire, they are supposed to extend the gear to extinguish it.

Apparantly, there was an incident where extending the gear did not extinguish the fire?

Is this true, and if so, do any of you guys have the details of the incident?

Thanks a million!

Very tough question in its wording. Perhaps we could make better sense out of our answers if you would parse your statements into sentences ending with question marks. I tried reading this several times and really didn't wish to go into a wide ranging discussion unless/until I understood what you are trying to ask.

On the surface your opening is a statement about Boeing procedures. Sounds like a standard procedure to me and no questions asked.

Then you move into a vague rumor about an incident where the Boeing procedure may not have had an effect and ask for the details.

Without knowing the specific incident I don't see how one can be specific about details.

So without stating details an answer could only be general.

Most causes of wheel well fire detection are hot brakes. Some of these if not attended to can result in the tire rupturing and damaging the wheel well resulting in flamable fluid release (hydraulic fluid or in some Boeing aircraft APU associated fuel). If a flamable fluid gets involved then the fire can progress into duct work etc (as it did in the Mexicana crash). Once in the ductwork progression moved all the way to the tail resulting in the tail separating in-flight.. The planes FDR revealed that previous flights had extended takeoff runs indicative of dragging brakes.)

So one answer to a possible question is what does extending the gear have to do with this? The answer is that it is a second line of defense in that it cools down an abnormaly hot brake before it causes a tire burst while stored in the wheel well. (the first line of defense is to not continue a takeoff roll out of spec)

If your questions are meant to go beyond my simplification then please clarify.

[galaxy flyer]

To frighten all the Boeing guys, there is NO Wheel Well Fire warning sys on AB.

AND....

the brake temp ind sys may be inop.....as well as tyre press sys, if installed.......

And they got this by the regulatory authorities how? Even the Challenger has gear bay warnings.

GF

[matkat]

In my distant past I was involved in an incident with a VC 10 en route Leuchars to Brize around xmas time 1988 (IIRC) we brought to attention of both the flight and ground eng. our concerns over a worn tyre it would appear that they did not take our advice and had a bit of the get it home syndrom, all was well until at top of climb the said tyre let go in the wheel well and took out the fuel lines for 2 engines with a subsequent emergency landing into Brize on a foamed runway:=

[galaxy flyer]

Matkat

But, the landing was at HOME!! :D

[Fargoo]

And they got this by the regulatory authorities how? Even the Challenger has gear bay warnings.

GF

It got by the regulatory authorities because it isn't required by the regulations.

[hetfield]

It got by the regulatory authorities because it isn't required by the regulations.Sad but true. Nothing learnt from:

http://208.37.5.10/ap/ap_sep93.pdf


"The Saudi report recommended that all transport aircraft be equipped with wheel well overheat and fire detectors, wheel well fire protection, brake temperature sensors, tire pressure sensors and corresponding indicators in the cockpit."
Wheel well overheat and fire detectors? My plane hasn't.
Wheel well fire protection? My plane hasn't.
Tire pressure sensors and corresponding indicators in the cockpit? My plane hasn't.
Brake temp indication may be inop acc. MEL.:ouch:

[gengis]

The 747-400 QRH: "8.36 FIRE WHEEL WELL... Condition: Fire is detected in a main wheel well."