744 Freighter Main Deck Fire Suppression
 

Having recently converted to freighters I am left wondering if the main deck fire drill would work in practice ...

It depressurizes the a/c to 25,000ft ... I presume to starve any fire of oxygen?

It scares me their is no fire extinguiser system like in the holds.

I wonder if Mr Boeing has tested the drill?

There's no main deck fire suppression system on the passenger variant either. Just you, some trolley dollies and about 3 minutes worth of BCF extinguishers. At least you can depressurize cabin on the freighter!!!

At least you know well before the fire 'takes hold' on a pax version, and have 12+ fire fighting trained trolley dollies!

On a frieghter their is no one down there, totally reliant on smoke detectors which might not trigger until the fire is well established ....

PS: You want to see some of the dangerous goods we carry on freighters ....

It's the smoke that affects crew and pax first. The advice to switch off the 2 packs and allow the aircraft to depressurize to 25,000ft, is to minimise the oxygen flow and suppress the fire, however, you still have, statistically, only about 15-18 minutes to land the aircraft (either on land or by ditching), if the source of the smoke/fire cannot be extinguished. As for dangerous goods on freighters, perhaps you should ask security agents what items they discover in pax hand luggage! These are, of course, undeclared and ill-packed dangerous goods.

Care to name your source on that?

The lack of any attempt at cargo fire fighting main or lower deck on a range of freighters is a distinct worry. Thing is there is so much stuff that could burn you'd end up offloading most of the payload to lift enough BCF.

the magic 17 minutes you have left till you die comes from a simple averaging calculation. in one case control was lost after 9 minutes, in another it took 25, so some smart guy came up with (YES!) 17 minutes.
and one of the situations i think about a lot.
if you ditch it, they will blame you for sinking a still-flyable plane in the ocean.
because you can't proof to them that you would have lost control some minutes later.
and if you don't ditch it, the report will state you were "too mission-minded/target-fixated"...

The source is from an article written by Bill Melvin of International Civil Aviation University. He mentions the SAA 747 Combi as "lasted twelve minutes" and the Swissair 111 (MD11) which "disappeared from radar within this time". Also in the same Safety magazine is a transcript of Fedex 1406 which diverted into Stewart International Airport, Newburgh, landing 18 minutes after a cargo fire warning (all crew members survived).
Personally I wouldn't care what any management felt about my decision to land as soon as possible, following a cargo fire/smoke warning. Perhaps you have different priorities or logical thinking? At least if you survive, you live to 'fight your corner'!

Go here http://www.smartcockpit.com/pdf/flig...nfactors/0009/

Open the file, its a pdf ... How To Deal With An In Flight Fire, by Bill Melvin ... thought provoking reading.

I personally would do the drill, then go and have a look wearing oxygen mask/smoke hood to see if it was a real fire ... if it was, then consider ditching ... the situation 'mid Africa' at night 500 miles from an airfield poses an interesting dilema.

Having a "lookee-see" on a 2-man crew freighter may impose a very high workload on the remaining pilot, and what exactly would you achieve? On a fully-loaded freighter, the space to determine where the source of the smoke/fire, is very limited and vision will not be too good with the smoke mask/goggles on. Better to seek a near landing site and proceed at high speed, while communicating your plight with all and sundry. After all, if Boeing consider 25,000ft to be the cabin altitude at which the fire will be suppressed, how long would you stay at that cabin altitude before commencing a rapid descent into thicker oxygen, which may cause the fire to flare up again?

Skiesfull - Mid atlantic their are times when we are 1.5hr flying from ANY tarmac.

I aint going to sit their for 1.5hrs wondering if it the warning is false or real having done the drill ... It I go down the back and its ablaze then ditching becomes the only option ....

I suspect the 25,000ft de-pressurisation drill is just to satisfy the certifaction requirments ... people climb Everest at >20,000ft and light fires?

Noblues
It is,as always, your call on the day. You should have an extra large Halon extinguisher and extension applicator on the main deck to carry to the source of the fire and try to extinguish it. I hope that such a scenario does not occur to you wherever you may be flying - it is one that is all too often out of the pilot's control, especially on a 2-crew flight.

Er you are aware that the main deck on the 757 is 14 pallet positions long and there is no access beyond the first one. Unless you have a 30 METER extension applicator and one which could drill through the floor to the belly holds as well then its a non starter.

Daysleeper,
The post is about the B744 freighter, not the B757! Back to sleep!

... the concern, though, is very valid. Many, if not all, freighter pilots have just the same sort of concern .. I know I did in a previous life ..

Dive & depressurize.

Read up on Class E cargo compartment.

The 744F QRH depressurises first (using the main deck cargo fire switch) then is slightly ambigous about when to decend to FL250. It maybe be prudent to stay at higher levels where their is less oxygen?

JT
I totally agree - it is a very uncomfortable thought, not only across the Atlantic but anywhere not built up, including Oz.
Noblues
Definitely not - don't hang around at altitude unnecessarily, you may suppress the fire but not completely extinguish it. Treat any warning for real, survive it and let the experts determine the cause of the warning. Carrying an oxygen bottle with a smoke mask and then trying to carry a 32 lbs weight Halon extinguisher and extension applicator is not an easy task, and will take you away from the important job of landing at the nearest suitable airport, or ditching if absolutely necessary.

Interesting document on automatic fire detectors in aircraft cargo departments.
http://www.fire.nist.gov/bfrlpubs/fire01/PDF/f01116.pdf
From the introduction, they state that only 1 in 200 warnings are real.
Not to say any warning should be ignored, but statistically its reassuring.

but what
 

skyefull,
good point to a short haul operation, but what do you do on a akl--lax flt???
I'd rather have some quick glance down than to ditch a perfectly good 744 for no reason. It might even take the commander to suffer since any normal F/O could land it without me if there's no real fire and I'll trip over at anybchance without the real thing-in the line of duty at the end of my days!!!

It's your call, as I've said before. A glance down the tops of the freight from the stairs, may be enough to convince you that it has been a false warning, but I'll bet anything that you and your crew member will wonder if it really was false! Follow your airline's advice/SOP's regarding Main deck and lower-lobe fire warnings - but it will always be your call on the day.Happy landings!