Starlionblue From Greenland, joined Feb 2004, 13606 posts, RR: 68 Reply 1, posted (4 years 4 months 2 weeks 21 hours ago) and read 2691 times:
< speculation >
- Different material composition compared to fuse.
- Far enough away from source of fire that the fire services managed to keep the fire from reaching the wings.
- Fire started in fuse tank, not wing tanks.
< /speculation >
Tact Is For People Who Aren't Witty Enough To Be Sarcastic
SlamClick From United States, joined Nov 2003, 9996 posts, RR: 79 Reply 3, posted (4 years 4 months 2 weeks 20 hours ago) and read 2651 times:
It appears also that the CFR crews were able to contain the fire, they were just unable to put it out until after it had consumed most of the fuselage. Possibly they were also able to keep it from burning into the tanks.
I was wondering much the same thing as I watched the video of it burning. The fire seemed to be mostly confined to the cabin area. And we thought they made the upholstery out of fire resistant materials!
Happiness is not seeing another trite Ste. Maarten photo all week long.
Flightopsguy From United States, joined Jan 2005, 324 posts, RR: 0 Reply 5, posted (4 years 4 months 2 weeks 17 hours ago) and read 2571 times:
Usually the center tank is emptied first. But I really don't know the 340. Could the ignition source have been the overheated main gear brakes? Ever see the max brake energy trial films? The brakes actually glow white and as the perf book sez "may catch fire".
VC-10 From United Kingdom, joined Oct 1999, 3636 posts, RR: 50 Reply 6, posted (4 years 4 months 2 weeks 17 hours ago) and read 2567 times:
The trim tank will empty of any fuel it contains during descent as the a/c passes through FL 245 or FMGS <75mins to destination. This fuel will transfer either to the wings, if there is space, or the centre tank if the wings are full. As mentioned the Centre Tank will empty first followed by the Inner Wing Tanks with the Outer Tanks tranferring to the inners when Inner Tank qty reaches 3.5 Tonnes.
Fokker Lover From , joined Dec 1969, posts, RR: Reply 7, posted (4 years 4 months 2 weeks 14 hours ago) and read 2512 times:
Contrary to what the NTSB wants you to believe, there isn't enough oxygen in the fuel tanks to support combustion. I wouldn't expect them to burn (or explode for no reason) unless they were ripped open.
Skydrol From Canada, joined Oct 2003, 681 posts, RR: 15 Reply 8, posted (4 years 4 months 2 weeks 14 hours ago) and read 2507 times:
Quoting Fokker Lover (Reply 7): Contrary to what the NTSB wants you to believe, there isn't enough oxygen in the fuel tanks to support combustion. I wouldn't expect them to burn (or explode for no reason) unless they were ripped open.
That's interesting. I always thought aircraft fuel tanks were vented, I was not aware they are made inert.
Bhill From United States, joined Sep 2001, 522 posts, RR: 0 Reply 9, posted (4 years 4 months 2 weeks 14 hours ago) and read 2507 times:
Not to be a smart ass, but the physics dictated they did not get hot enough..either because of the lack of fuel or O2..seems the fire fighters made sure that either they kept it cool enough or put enough foam on to starve the O2 supply..suffocation..works the same way in humans on the mitochrondial level
Fokker Lover From , joined Dec 1969, posts, RR: Reply 10, posted (4 years 4 months 2 weeks 13 hours ago) and read 2495 times:
Quoting Skydrol (Reply 8): That's interesting. I always thought aircraft fuel tanks were vented, I was not aware they are made inert.
You are correct they are vented to atmosphere to equalize pressure. That doesn't mean that the oxygen comes rushing in though. Open up a freshly drained tank and use a sniffer. You'd be surprised at how low the oxygen percentage is. We enter tanks at 19% up to 21%, Above 21% the explosion hazard increases. Below 19% you go to sleep and die. I've sniffed out tanks that were 2% oxygen when I opened them.
Go to sleep maybe, but you won't die. A dip from 21% to 19% translates into an effective altitude increase of about 7000 feet from current (based on partial pressures)...Unless you're in Denver or are a chain-smoker, that shouldn't pose too much of a problem.
Also, when we exhale, the oxygen content of our breath is still about 19% or so...how would something like CPR work if it wasn't? You can easily keep someone alive with that amount of oxygen in the air.
SlamClick From United States, joined Nov 2003, 9996 posts, RR: 79 Reply 13, posted (4 years 4 months 2 weeks 4 hours ago) and read 2355 times:
Quoting MrChips (Reply 11): when we exhale, the oxygen content of our breath is still about 19% or so...how would something like CPR work if it wasn't? You can easily keep someone alive with that amount of oxygen in the air.
Two answers:
1. When we do CPR we are not holding the air in our lungs long enough to transfer the oxygen. It is just a quick intake and explusion.
2. You said it yourself - partial pressure of oxygen. We will breathe into the patient at more than one atmosphere. Result is more than enough oxygen to revive them.
You are spot-on about the slightly reduced pressure. People live in places in the Andes or Himalayas with only a little adaptation for the reduced atmospheric pressure. They are not a separate species.
Happiness is not seeing another trite Ste. Maarten photo all week long.
Fokker Lover From , joined Dec 1969, posts, RR: Reply 14, posted (4 years 4 months 2 weeks 3 hours ago) and read 2339 times:
Quoting SlamClick (Reply 13): People live in places in the Andes or Himalayas with only a little adaptation for the reduced atmospheric pressure.
Absolutely true, but they don't have to be concerned about volatile organic compounds(VOC's). Being in a confined area there are more issues than just lack of oxygen. Plus jet fuel doesn't ignite as easily as you would think.
All EPA guys, please close your eyes. I once dumped a quart of jet fuel on the concrete and tried to light it. It took a real damn effort to finally get it to burn.
Fokker Lover From , joined Dec 1969, posts, RR: Reply 15, posted (4 years 4 months 2 weeks 3 hours ago) and read 2331 times:
I also forgot to ad that 19% is our safety cut off point for not wearing a forced air breathing system. I'm sure that there is a margin of error built in there. A lot of the times we wear the masks just to keep cool and combat the fumes which are nauseating. No matter what the meter is reading.
777236ER From United Kingdom, joined Aug 2001, 12706 posts, RR: 58 Reply 16, posted (4 years 4 months 2 weeks 3 hours ago) and read 2317 times:
Re. oxygen,
21%, normal concentration. 17%, respitaion volue increased, muscular coordination diminished, more effort required for attention and clear thought. 12-15%, shortness of breath, headache, dizziness, quickened pulse, fatigue upon exertion, loss of muscular coordination. 10-14%, faulty judgement. 10-12%, nausea and vomitting, exertion impossible. 6-8%, collapse and unconsciousness, but rapid treatment can prevent death. 6-3%, death in 6-8 minutes. 2-3%, death in 45 seconds.
SlamClick From United States, joined Nov 2003, 9996 posts, RR: 79 Reply 17, posted (4 years 4 months 2 weeks 2 hours ago) and read 2312 times:
Quoting Fokker Lover (Reply 14): All EPA guys, please close your eyes. I once dumped a quart of jet fuel on the concrete and tried to light it. It took a real damn effort to finally get it to burn.
I read once that Sir Frank Whittle once stood in a big puddle of jet fuel with a lighted cigar to demonstrate how much safer than avgas it was. That true?
Happiness is not seeing another trite Ste. Maarten photo all week long.
Avioniker From United States, joined Dec 2001, 1098 posts, RR: 17 Reply 18, posted (4 years 4 months 1 week 5 days 6 hours ago) and read 2037 times:
Fokker Lover,
Your choice of moniker showing a love for an aircraft that kept too many mechanics too busy aside;
I'm delighted to see that someone remembers why the engineers in the 40's and 50's knew that it was perfectly safe to run wiring through fuel cells because they couldn't possibly cause combustion.
Anyone who remembers their Jr. High science classes (as were taught in the 50's and 60's before they needed a bigger, more important sounding name like "Middle School") knows that any hydrocarbon based fuel in an enclosed area will expand exponentially to fill the area until pressure is equalized and displace the lighter air and oxygen making combustion virtually impossible.
One of the demonstrations used in the Air Force's POL school was attempting to ignite JP4 in a bucket with any type of open flame. The deeper the bucket the more difficult to achieve combustion. We were encouraged to throw lit matches into a 2.5 gallon bucket with one gallon of JP4 in it. They went out before hitting the liquid fuel. The only time we could get the vapours to iginte was when we threw the match while it was still flaring immediately after being struck.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
While certain hydrocarbons will produce a mixture too rich or too poor to burn at usual temperatures when in an enclosed space, it is not as simple as "enclosed hydrocarbons do not burn".
KhenleyDIA From Sweden, joined Feb 2005, 397 posts, RR: 0 Reply 20, posted (4 years 4 months 1 week 5 days 2 hours ago) and read 1943 times:
Another thing that I didn't see pointed out is that if there was a fire inside the plane, it would have been hard to reach. The contents inside the cabin of the plane burn REALLY well and can take a while to put out. Not to mention, access to the plane at first was difficult, at best. Since all people were out, no point in endangering other lives to save a ruined airplane.
KhenleyDIA
Why sit at home and do nothing when you can travel the world.
Kaddyuk From Wallis And Futuna Islands, joined Nov 2001, 4125 posts, RR: 39 Reply 21, posted (4 years 4 months 1 week 5 days 2 hours ago) and read 1912 times:
Quoting Starlionblue (Reply 12): Wing fuel is always used last since it decreases wing bending moment and thus decreases stress on the wing.
Nope, Wing Fuel costs nothing to carry. Because Mr Newton says so.
Because the wings are the carrier of the fuse, if you are going to add weight to an aircraft (through more fuel) add it to the wing tanks. that is why wing tanks are bigger than the centre tanks and also why airlines avoid filling the center tank before the wings.
Whoever said "laughter is the best medicine" never had Gonorrhea
Litz From United States, joined Dec 2003, 1553 posts, RR: 0 Reply 22, posted (4 years 4 months 1 week 5 days 1 hour ago) and read 1890 times:
Quoting SlamClick (Reply 3): I was wondering much the same thing as I watched the video of it burning. The fire seemed to be mostly confined to the cabin area. And we thought they made the upholstery out of fire resistant materials!
Fire resistant yes ... Fire proof no ...
The materials are designed to delay catching on fire (and releasing all those noxious "burning synethic materials" vapors) long enough to allow a reasonable time for passenger evacuation.
And in this case, that worked just fine ...
Once the modern materials do catch, however, they burn just as ferociously as you might imagine an airplane fire could be ...
Quoting Mrocktor (Reply 19): The only time we could get the vapours to iginte was when we threw the match while it was still flaring immediately after being struck. Smile
Betcha that was more the heat from the phosphor on the matchhead, then it was the actual flame ... still shows how hard it is to get nonvaporous jet fuel to ignite.
I'd be very interested to find out from passengers or investigators if there was a fuel fire indeed on that plane (should have been a very strong jet fuel odor, in that case), or if that was merely either friction, brake or maybe hydraulic fluid that touched the fire off (or a broken fuel LINE, maybe to an apu) or something ...
BuyantUkhaa From Mongolia, joined May 2004, 2501 posts, RR: 3 Reply 23, posted (4 years 4 months 1 week 4 days 20 hours ago) and read 1801 times:
Quoting Kaddyuk (Reply 21): Because the wings are the carrier of the fuse, if you are going to add weight to an aircraft (through more fuel) add it to the wing tanks. that is why wing tanks are bigger than the centre tanks and also why airlines avoid filling the center tank before the wings.
Err... are you familiar with the concept of the bending moment? The lift forces the wing to bend up, which to some extent is counteracted by the fuel in the wings. This is especially important for planes with rear-mounted engines, as wing-mounted engines also compensate for the bending moment generated by lift.
Quoting Kaddyuk (Reply 21): Nope, Wing Fuel costs nothing to carry. Because Mr Newton says so.
Well, I'd say most airlines would profoundly disagree with Newton here...
Starlionblue From Greenland, joined Feb 2004, 13606 posts, RR: 68 Reply 24, posted (4 years 4 months 1 week 4 days 18 hours ago) and read 1766 times:
Quoting Kaddyuk (Reply 21): Quoting Starlionblue (Reply 12):
Wing fuel is always used last since it decreases wing bending moment and thus decreases stress on the wing.
Nope, Wing Fuel costs nothing to carry. Because Mr Newton says so.
Because the wings are the carrier of the fuse, if you are going to add weight to an aircraft (through more fuel) add it to the wing tanks. that is why wing tanks are bigger than the centre tanks and also why airlines avoid filling the center tank before the wings.
How can you say "nope" and then agree with me But then you go off on a tangent I'm afraid.
As I said, wing fuel is used last because it decreases wing bending moment. However, the fuel cost of carrying fuel doesn't change regardless of where it is placed. Weight is weight.
Wing tanks are typically bigger than fuse tanks because:
- They decrease wing bending moment.
- They don't take up precious cargo space.
Tact Is For People Who Aren't Witty Enough To Be Sarcastic
Abbs380 From United States, joined Mar 2005, 120 posts, RR: 0 Reply 25, posted (4 years 4 months 1 week 4 days 10 hours ago) and read 1697 times:
I cant agree on all points. But on every large a/c I have worked the center tank fuel is the first to go, the most outboard fuel is the last to go. Its has gotten to the point now that on an A-300, if it is down for more than 6 hours, you have to transfer the outer tank fuel into the inner tanks. This is because outer tank fuel is used last, and could conceivably not be used for months if an a/c only flew short trips.
26 Okie: First of all let me qualify here before I get flamed because I do not know the exact circumstances that were going on with the Fire Dept. whether the
27 SlamClick: Well hell! If it costs nothing to carry fuel in the wing tanks then lets put some wings up there, full of fuel - use them like gas stations in the sk
28 JDD1: Click on the following to get a description of the A340 fuel system from the Airbus' FAST magazine. http://www.content.airbusworld.com/S...es/html/acr
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But then you go off on a tangent I'm afraid.
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