View Full Version : 744 Freighter Main Deck Fire Suppression
noblues
24th Jul 2007, 10:46
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?
Carnage Matey!
24th Jul 2007, 14:43
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!!!
noblues
24th Jul 2007, 16:14
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 ....
skiesfull
24th Jul 2007, 16:49
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.
Daysleeper
24th Jul 2007, 16:56
you still have, statistically, only about 15-18 minutes to land the aircraft
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.
FCS Explorer
24th Jul 2007, 17:48
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"...
skiesfull
24th Jul 2007, 18:55
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'!
noblues
24th Jul 2007, 20:23
Go here http://www.smartcockpit.com/pdf/flightops/humanfactors/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.
skiesfull
24th Jul 2007, 21:56
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?
noblues
25th Jul 2007, 09:43
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?
skiesfull
25th Jul 2007, 13:02
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.
Daysleeper
25th Jul 2007, 18:29
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
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.
skiesfull
25th Jul 2007, 18:37
Daysleeper,
The post is about the B744 freighter, not the B757! Back to sleep!
john_tullamarine
25th Jul 2007, 23:11
... 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.
noblues
26th Jul 2007, 10:24
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?
skiesfull
26th Jul 2007, 10:35
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.
noblues
26th Jul 2007, 14:34
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.
16down2togo
27th Jul 2007, 19:11
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!!!
skiesfull
27th Jul 2007, 19:31
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!
Brian Abraham
28th Jul 2007, 04:39
noblues - one you may be interested in.
On 28-Nov-1987, a South African Airways Boeing B747-244B Combi, registered as ZS-SAS, lost control and crashed into the Indian Ocean near Mauritius. The aircraft was destroyed. There were 19 crewmembers and 140 passengers aboard, all were fatally injured.
At 23:48 UTC, the pilot of the Boeing B747 reported an emergency descent due to smoke in the aircraft to FL140 and requested emergency services at Plaisance Airport. At 00:07 the aircraft crashed into the sea, 134nm northeast of Mauritius and was 13 hours later. Three minutes earlier the pilot had acknowledged an instruction from Mauritius approach control to report at FL50.
Analysis of recorders, all salvaged from the seabed at 4500m, indicated that the crew was alerted by the smoke detection system to a fire in the right forward pallet, in the main deck cargo compartment. Evidence of the presence of smoke was found in the passenger cabin and galley and in the passenger trachea. The aircraft crashed because of the fire damage to the controls, or crew incapacitation, or crew distraction or a combination of these factors. The crew may have not been able to deal with the fire.
FAA Airworthiness Directive 89-18-12 R1 has been promulgated.
Safety recommendations: installation of additional area microphones, increased recording time for the cockpit voice recorder and additional time sequence underwater locator beacons for the flight recorders.
http://en.wikipedia.org/wiki/South_African_Airways_flight_295 has some back ground and the controvesy surrounding the accident.
Portion of CVR at http://www.planecrashinfo.com/cvr871128.htm
Jon Lei
28th Jul 2007, 04:49
Hi all, just wondering..
1) Can the main deck depressurise on the 744F without the upper deck depressurising ( with the staircase fire resistant door shut) during a fire sw activation?
2) Simmilary, is it possible for the flight deck, equipped with a bullet proof door with no blow out panels, to remain pressurised in an event of a cabin decompression on the 744 pax version?
3) How many O2 bottles does the 744F have for the cockpit crew and upper deck occupants respectively?
4) Why does the 744F MTOW decrease when the fuel density is below 0.78?
5) Why does the 744F MTOW decrease when the ZFW increases beyond 276T?
Thank you in advance. Cheers.
JL
1. No.
2. Not too familiar with pax version, but doubt it.
3. Hmm. Think its 2 in the fwd belly?
4. It does? Thought that was on some converted classics.
5. 276T-288T is what is known as Extended (or Variable) ZFW. Its a trade off of carrying a higher payload against a lower take-off weight. Useful for shorter trips.
skiesfull
28th Jul 2007, 11:59
JonLei
2) No
3) If it's portable O2 bottles that you are referring to then I think it's one each for all (max) 8 occupants.
4) Didn't know there was a reduction - if there is it will be in Fluid Replenishment Manual (ground handling).
[edited: sorry, I was mixing up things...] We have 195 minutes of oxygen for evry occupant to cover some very high terrain in China with decompression i.c.w. few available options to divert. A main deck fire would not make things easier.
With a fire on the main deck or the lower cargo holds, I am not sure if we would see smoke in the cockpit without recirculated air. With only an EICAS warning, there's i.m.h.o. not enough info to justify ditching as mentioned earlier until the soles of your shoes start melting.
On our combi's we obviously do have a main deck fire extinguishing system.
Cheers...
BANANASBANANAS
2nd Aug 2007, 20:57
Interesting thread chaps.
Not sure if this is relevant to B744F ops but my previous airline (B763) had some literature which stated that from the moment an in flight cabin fire was declared to be out of control, structural break up could be expected after as little as 12 minutes. Now, if you are at 36,000 feet when the fire starts raging it just about leaves you enough time for a max rate descent and a ditching/crash landing.
Scary!
noblues
5th Aug 2007, 12:39
I dont think there is a right or wrong answer to this debate ....
The way I would deal with a main deck fire EICAS would be very different depending how far away I was from a usable runway.
A friend recently said to me that compared to PAX 74's we are at an advantage ... upon asking - why? He said everything on a 744F is checked for dangerous goods HAZMAT etc and packaged accordingly. In the hold of a PAX a/c all sorts could be in those suitcases ...
Also on a the main deck of a 744F their is very little wiring (ie. IFE) to spark off a fire ....
The weak link in cargo is the load controllers and shipping agents, trusting the packaging and loading UN instructions have been adhered to.
The "weak link" is anyone but the loadmaster/controller.
Any guesses to the reasons why?
:rolleyes:
noblues
5th Aug 2007, 21:07
The "weak link" is anyone but the loadmaster/controller.
Any guesses to the reasons why?
CR2 - Uhhmm, go on!
(The packaging shippers etc? The sender not correctly identifying the contents?).
skiesfull
5th Aug 2007, 22:02
NOBLUES
welcome to the world of the "Freight-Dog" - you gotta have faith!
Should you ever be unfortunate to have experience of a main deck fire warning and walk away from it, - be sure to let us know everything you did to survive.
I remember 15yr ago doing a mod on the Air India combie classics to install 10 fire ext bottles in the lower lobe aft cargo r/h sidewall, this was for main deck fire ext.