Nitrogen in Fuel Tanks

[Cusco]

I posted this on another Forum, but on reflection I figure I'm more likely to get a response here: Any help gratefully received


I was watching on Sky last night a spin-off to those awful 'Air Crash Investigation' programmes entitled something like 'Crashes that changed flying'

One section related to a 747 which was delayed fully loaded on the stand on a hot day for over 4 hours while a misplaced piece of baggage was found.

Shortly after takeoff it exploded killing all on board.

Turned out that while on the ground, the airconditioning plants, situated directly under the main fuselage fuel tank had quielty cooked up the (virtually empty) main fuselage tank and resultant vapour was ignited by faulty insulation in a fuel gauge sender circuit.

Now this is the bit I need help with: As a result of this a gismo was developed which has subsequently fitted to all passenger jets which filters oxygen out of the air via fine filtersso that the resultant remaining nitrogen can be fed into the fuel tank airspace, reducing explosion risk.

Filters out the oxygen? How does that work? I guess yer average coffee filter paper wouldn't work?

Any Commercial Jet engineers here could explain this to me/ tell me what this gismo is called? I've tried googleing without success and am fascinated to know how air can be broken down by filtration alone in a gadget small enough to shove in all airliners.

Thanks in advance.


Cusco

[MLT]

Google OBIGGS (On Board Inert Gas Generation Systems):

Honeywell's version:

On-Board Inert Gas Generation System (OBIGGS) - Honeywell Aerospace Engineering (http://www51.honeywell.com/aero/technology/trends3/solutions3/obiggs.html?c=13)

Parker's version:

http://www.parker.com/literature/Air%20&%20Fuel%20Division/AFD%20Static%20Files%20for%20Literature/AFD.fuel.tank.inerting.pdf

NASA OBIGGS Test:

http://www.fire.tc.faa.gov/pdf/04-41.pdf

In short, they work a bit like your cars catalytic converter.

[Cusco]

MLT:

Just what I wanted.

Thanks a million.

Cusco.

[hawker man]

Google SFAR88 this is what come out after the TWA 800 crash.
The Nitrogen system even has its own ATA chapter 47

[SNS3Guppy]

Presumably the original poster is talking about TWA 800.
Turned out that while on the ground, the airconditioning plants, situated directly under the main fuselage fuel tank had quielty cooked up the (virtually empty) main fuselage tank and resultant vapour was ignited by faulty insulation in a fuel gauge sender circuit.


No 747's have simply taken off and exploded.

"Air conditioning plants" don't cook up the fuel tank, or fuel for that matter.

In the B747, the center wing tank presently has minimum fuel quantities when fuel is to be placed in the tank, based on speculation from the TWA 800 investigation. These AD's only apply when fuel is to be used from the CWT, and even then they're only applicable to certain segments of flight.

TWA 800 was shot down. It did not simply "blow up."

Further, the fuel gauges in the 747 CWT and wings are capacitance gauges, passive, ant not implicated and not accused of being the culprit. The current "fix" Airworthiness Directive addressing the matter requires minimum quantities of fuel in the tank when the tank is used, and that's all...never any suggestion, inference, or hinting at a need to inert anything, address "fuel sender gauge circuits," or anything of the sort.

Nitrogen systems, such as those used in the C-17, can be troublesome. The system on the C-17 in particular was originally conceived not with the concept of daily routine operation, but the prevention of a flash or explosion following a weapons strike. It's intended to make the aircraft more survivable in combat.

This is not generally a necessity for the B747 in passenger or freight service, save for TWA-800, of course. Even then, whereas the heat source for the target was the packs, which are located beneath the center wing tank, filling the tank with nitrogen wouldn't have helped them.

In most flight operations, the CWT seldom gets used.

In 1976 an Iranian 747 crashed following wing failure, the result of an explosion caused by a lightening strike. The lightening has been determined a likely contributing factor, although other ignition points have also been cited, including a fuel pump. A key issue for the aircraft, however isn't just the lightening or fuel pump issues, but that the aircraft wasn't using straight kerosine fuels; it was using a cut fuel, JP4, which is both kerosine and gasoline combined. This is considerably more volatile than straight jet fuel. The incident is sometimes used as a reference in a call for inert gas in fuel tanks, but those using it as an example seldom remember to note that there's never been an explosion from lightening based on JetA (kerosine-only).

Now this is the bit I need help with: As a result of this a gismo was developed which has subsequently fitted to all passenger jets which filters oxygen out of the air via fine filtersso that the resultant remaining nitrogen can be fed into the fuel tank airspace, reducing explosion risk.


This is untrue, and there is no such device fitted to the B747, nor mofidication used which would accomplish such a thing.

SFAR 88 has nothing to do with inerting tanks. It was a special federal aviation regulation citing a requirement to inspect existing and future fuel tanks and systems for potential ignition sources, and to ensure that no such sources were available in the tanks.

[galaxy flyer]

TWA 800 was shot down. It did not simply "blow up."

Guppy

Any proof on that? Like an accident report or criminal investigation? That story is as realistic as the US Government causing 9/11.

Two Lockheed products had nitrogen inerting systems-the SR-71 and the C-5. The C-5 system removed dissolved oxygen in the fuel as it was boarded and used nitrogen to inert the ullage in the tanks. Two 750 pound nitrogen containers held liquid nitrogen for inerting and for fire protection in the pylons and dry bays.

GF

[SNS3Guppy]

I don't think there's any question that TWA 800 was shot down. I can tell you my personal beliefs, and I can't tell you certain things that I do know, given personal connections to the incident itself. I know very few who believe it was a fuel tank explosion, particularly among the Classic 747 crews and mechanics out there. I happen to be one of the 747 crewmembers which does not believe it was a fuel tank failure, and who does believe it was shot down. I also believe that asked candidly, you'll find that my point of view represents the majority of those with experience on type, and in particular among those with any association to the incident itself.

I can certainly point you to web sites which will address the situation...which you'll be quick to discredit, no doubt. You can certainly ignore the hundreds of witnesses who reported seeing a streak of light leave the surface and head skyward, then saw the explosion, and you can ignore the radar plots of a boat rapidly exiting the area, or the fact that commercial salvage and rescue was excluded by the US Navy...or the fact that recovery and investigation was handled not by the usual commercial and government sources but by the FBI and military.

You'll hear the nutcase conspiracy theories about a military coverup because of a military shootdown...which never held any water to begin with. You won't have to look far to see the truth, however, that TWA 800 was indeed shot down.

[GlueBall]

". . . TWA 800 was shot down. . . you'll find that my point of view represents the majority of those with experience on type."

I am an experienced nonmember of that "majority."

Notwithstanding that distant cousins of the 747 family, namely the 737 models have had dramatic center tank explosions right on the ramps at MNL & BKK. There is no "cover up" because the TWA800 entire center section fuselage is still well preserved [used by the NTSB for training purposes] and is available for re-inspections by missle theorists as you, SNS3Guppy. :ooh:

The ignition source originated from inside the CWT, and there is no external penetration evidence.

NTSB - TWA800 exhibits on the web (http://www.ntsb.gov/Events/twa800/exhibits_web.htm)

http://www.ntsb.gov/Events/twa800/exhibits/missileanalysis.pdf

[Fargoo]

I don't think there's any question that TWA 800 was shot down. I can tell you my personal beliefs, and I can't tell you certain things that I do know, given personal connections to the incident itself

Tinfoil hats on lads, they're coming for us :ugh:

[SNS3Guppy]

Interestingly, early in the investigation, officials at China Lake verified evidence of a missile attack. That the Navy was as heavily involved to the normal exclusion of all other recovery available has never been properly addressed; simply put, many were kept away for a very long time, evidence that others had was reclaimed and disappeared, and the matter conveniently was sewn up to show a center wing tank explosion.

Despite this, the "fix" has been to have a minimum of 17,000 gallons of fuel in the CWT if the fuel pumps are to be used. That's it. The big threat, and the fix is business is usual, with a little bit of fuel.

Smoke and mirrors. The US government simply didn't want to admit at the time that an aircraft had been shot down, and went to great pains to show the world that folks were safe within her borders.

The night it happened I remember seeing witness after eye witness interviewing on television, all telling chillingly identical tales of watching a streak of light go from the surface upward, and seeing the aircraft explode. All of a sudden those reports terminated, and were never discussed again. Go figure.

TWA 800 was shot down, and it was shot down in error when an El Al flight didn't get off the ground. Not a coincidence.

When the Clinton Administration undertook to cover the problem and show it as a mechanical failure, the terrorists found that they had to strike back with something that couldn't be covered up...and there was born the impetus that lead to the WTC attacks.

You're no different than many who are content to have the wool pulled over their eyes, but the truth is, TWA 800 was shot down.

[Fargoo]

Quote:
Now this is the bit I need help with: As a result of this a gismo was developed which has subsequently fitted to all passenger jets which filters oxygen out of the air via fine filtersso that the resultant remaining nitrogen can be fed into the fuel tank airspace, reducing explosion risk.
This is untrue, and there is no such device fitted to the B747, nor mofidication used which would accomplish such a thing.

As nitrogen inerting is soon to be mandated on new aircraft in the US, i'd say that statement isn't entirely true.
The nitrogen generation system (as fitted to the 777) is in fact an oxygen reducing system. It lowers the amount of oxygen in the centre tank to an "acceptable" level.

[Cusco]

Blimey!

The words 'opening ' 'of' worms' ' can' spring to mind.

I'll leave you conspiracy theorists to scrap amongst yourselves while I study the links on the Nitrogen gadget you all so helpfully provided.

Thanks and 'Bye

Cusco.

[leewan]

I remember watching a Discovery Channel programme on the TWA 800 crash a few years ago and all signs pointed to a cover up. Here are some reasons that i remember.
1. There was a mysterious radar blip heading towards the a/c seconds before the a/c disappeared from the radar screen.
2.A beach-goer at Long beach happened to take an innocent photo of someone and when looking closely at the photo after the film was developed, noticed a missile-like object with a smoke plume heading towards the sky around the same time the a/c crashed.( It was shown on the documentary) He gave it to the FBI and after a few weeks, their reply was, " It was not heading towards the a/c" or some dismissal like that.
3. There were traces of missile-launching rocket ingredients on the a/c fabrics. The official reply was they were remains from a bomb training exercise for K9s some time back.
4.Plenty of eye witnesses saw a flaming object heading towards the sky and then exploding into pieces. The NTSB's official video showed that what they saw was the a/c's aft fuselage with the wings climbing after the explosion and then disintergrating.The a/c fwd part and the aft part just after the leading edge actually managed to separate itself cleanly after an explosion ! What is even more boggling is that the aft part with the wings climbs with the fwd part missing. Aerodynamically, the drag from the missing nose will drag it down. That's what an aerodynamicist said on the interview.

I dunno what brought TWA 800 down, but I dun think it was a CWT explosion due to faulty FQIS.

[cessnapuppy]

If by 'causing' you mean hand training operatives and telling them what to do and blocking (both bureaucratically and directly) all actions both inadvertent or direct that would lead to the interception of the terrorists?

NO -hell no

If you mean being bumbling, inept, unable to link dots because of a disjointed and incoherent intelligence structure and poor hand off procedures* and information sharing policies (WHICH CONTINUES TO THIS DAY) the answer is a resounding YES


*Like the 400 Meters relay race, a 'hand off procedure' as with the baton is necessary because the CIA is precluded from operating of US soil.

What is even more boggling is that the aft part with the wings climbs with the fwd part missing. Aerodynamically, the drag from the missing nose will drag it down. That's what an aerodynamicist said on the interview
http://www.pprune.org/forums/images/smilies2/icon_rolleyes.gif what is even MORE boggling is the total ignorance of physics...
consider if you will that the 'aft part with the wings' is also the part with those noisy, THRUST PRODUCING hanging on things (engines). With the plane pointing up then separation or no, anything attached to those thrust producers (engines) will perhaps CONTINUE TO GO UP IRRESPECTIVE OF 'DRAG'

"aerodynamicist " my ass

If you are looking for a civilian shootdown, look at this Siberia Airlines Flight 1812 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Siberia_Airlines_Flight_1812)

[Blacksheep]

Who precisely is supposed to have shot down this aircraft? The Libyans perhaps? Or maybe it was Osama bin Laden? The USN or any other navy would never have been able to cover up such an accident, there would be far too many people to silence them all.

Then there is the inconvenient fact that several other Boeing aircraft have suffered fuel tank explosions - on the ground where investigation is possible. That's why we have all these inspections of the fuel tank wiring, including for chafing of the fuel pump wiring that runs through metal conduits within the tank. Wires have been found chafed through to the conductor and with signs of arcing on the conduits.

You may even be aware of the current Boeing FTRP Emerging Issue EM-09-00036 that affects Boeing B737, B747 and B767 aircraft as a result of a B737 opertor discovering chafed wires within a conduit just 21,000 flight hours after completing SB 737-28A1120?

This is an engineering forum where engineers discuss engineering matters, not conspiracy fantasies. :=

[leewan]

With the plane pointing up then separation or no, anything attached to those thrust producers (engines) will perhaps CONTINUE TO GO UP IRRESPECTIVE OF 'DRAG

Going by that logic, a/c will have to shut down their engines or jettison them all altogether in order to land or descend. :eek:


Basic aerodynamics states that in order for an a/c to climb, lift must be more than weight/gravity and thrust must be more than drag. I am not an expert aerodynamicist, but I'm pretty sure that an open cross section of a 747 fuselage( 3 decks) at a climbing speed will produce significant drag.

[cessnapuppy]

perhaps I was a wee bit lacking in self-moderation in my remarks earlier (which perhaps causes you now to harden your position)

Going by that logic, a/c will have to shut down their engines or jettison them all altogether in order to land or descend

Actually, what the pilots do, is
a) reduce thrust - kinda like shutting down the engines, but not all the way. Thinking of it as, taking your foot of the gas/throttle -but maintaining enough speed to maintain lift.

b) use the flappy things in the tail
c) lower the wheely rubbery things
d) do some things with the wings

Things called "spoilers" are also used. Contrary to popular opinion, 'spoilers' are not a row of people in the theater who shout out during the suspenseful bits

These all encourage the plane to go down, but under control.
(Forgive me if I get too technical.....)

[leewan]

Actually, what the pilots do, is
a) reduce thrust - kinda like shutting down the engines, but not all the way. Thinking of it as, taking your foot of the gas/throttle -but maintaining enough speed to maintain lift.

b) use the flappy things in the tail
c) lower the wheely rubbery things
d) do some things with the wings

Things called "spoilers" are also used. Contrary to popular opinion, 'spoilers' are not a row of people in the theater who shout out during the suspenseful bits

Yup, I know all of the above is needed to land the plane.

(Forgive me if I get too technical.....)

Not at all ! I actually prefer it that way. I work in the aviation engineering line, so your description of the landing procedure is way too simplified for my liking. :) Not to mention that i know it in the first place. I wrote the "shutting down engine for landing" statement in jest for your " continue to go up irrespective of drag" statement.
The fact that flaps and spoilers are used to increase drag and allow the a/c to descend contradict your bold(no pun intended :)) statement.

[TURIN]

Well if ever a thread should end up in JB this is it.

TWA 800 shot down, my arris.

No such thing as inerting systems, tosh.

BA's latest 777s have the inerting system fitted. Lots of safety awareness stuff going on regarding engineers working in the viscinity of such. Possibility of passing out due to lack of O2 and all that.

[hawker man]

All engineers now require fuel tank safety training level 2 for aircraft with a pay load above 7500lb or 30 passengers or more. Anything that can effect the fuel system is now considered cdccl = critical design control configeration limitation. This is an absoulte nightmare as far as certification is concerned.

[One Outsider]

Basic aerodynamics states that in order for an a/c to climb, lift must be more than weight/gravity and thrust must be more than drag.

Well Leewan, I suppose then that it should be easy for you to provide evidence for that claim.

Simple vectors and such, should suffice.

[SNS3Guppy]

All engineers now require fuel tank safety training level 2 for aircraft with a pay load above 7500lb or 30 passengers or more.


In the UK, you mean?

That wouldn't be 'all' engineers. Just some.

And yes, TWA 800 was shot down.

[hawker man]

Not just the Uk this is a EASA requirement but only for the Engineers who certify on the Aircraft that meet the 7500 pound or 30 passengers or more.

[violator]

Guppy

There are so many technical mistakes in your posts that is discredits you. In fact it's a poignant example of someone with a little bit of knowledge applying it too freely: making wild statements with clear factual errors.

"Air conditioning plants" don't cook up the fuel tank, or fuel for that matter.

The packs are a heat source near the centre fuel tank. Hence they patently do heat up the fuel.

Further, the fuel gauges in the 747 CWT and wings are capacitance gauges, passive

Capacitance probes, whether AC or DC, are not passive. They are active, energized with a hi-z current.

Even then, whereas the heat source for the target was the packs, which are located beneath the center wing tank, filling the tank with nitrogen wouldn't have helped them.

Ignoring your contradiction, of course inerting the ullage would have helped. Liquid aviation fuel doesn't burn, its vapour does. Hot fuel and an inert ullage is not flammable. Filling the tanks with nitrogen would have prevented the explosion.

In most flight operations, the CWT seldom gets used

Empty tanks are the worst case - the entire tank is vapour.

Despite this, the "fix" has been to have a minimum of 17,000 gallons of fuel in the CWT if the fuel pumps are to be used. That's it. The big threat, and the fix is business is usual, with a little bit of fuel.

To prevent dry-running. You don't seem to realise it's fuel vapour which ignites, not liquid fuel. No oxygen, no fire.

[SNS3Guppy]

The packs are a heat source near the centre fuel tank. Hence they patently do heat up the fuel.


Packs cause heat, and were most likely the heat source for the missile. Packs do not "cook up" the fuel, nor do the packs use up the fuel, nor has heating of center wing tank fuel by proximity of the packs been responsible for a CWT exploding. Accordingly, my statement was correct.

Capacitance probes, whether AC or DC, are not passive. They are active, energized with a hi-z current.


The capacitance probes did not, do not, and have not represented an ignition source, and are a passive source of fuel sampling (as opposed to float gauges or another electromechanical source). Accordingly, my statement was correct.

Ignoring your contradiction, of course inerting the ullage would have helped. Liquid aviation fuel doesn't burn, its vapour does. Hot fuel and an inert ullage is not flammable. Filling the tanks with nitrogen would have prevented the explosion.


No, in fact; it wouldn't. A missile strike in proximity to the fuel tanks would have caused plastic deformation of the fuel cell (which it did), and most likely expansive deformation of the wing tanks as well (which it did). Aside from the plastic deformation, rupture of the tank occurred, meaning that as fuel exits the cell, and vapor, the presence of nitrogen in the cell is irrelevant; it's going to burn and explode anyway. Accordingly, my statement was correct.

Everything burns, and everything vaporizes before it burns as part of the chemical process of pyrolysis. This is a given. With rupture of a fuel cell, however, nitrogen in the tank does noting to prevent a subsequent explosion. Nitrogen in the tank will suppress arcing from a contained ignition source, but this wasn't the case.

Empty tanks are the worst case - the entire tank is vapour.


Quite correct. However, you're responding to a statement that the CWT wasn't used, and not being used, the alleged ignition source, the fuel transfer pump, was deactivated and also not in use...meaning the source claimed to have triggered the explosion wasn't active or energized.

A tank which is vapor doesn't necessarily burn or explode until a combustible mixture is reached, and thus the notion that simply because the tank does not contain fuel makes it likely to explode is in error. Moreover, currently the 747 continues to fly with empty center wing tanks, and the only requirement to address this matter is that if any fuel is to be used from the tank, it have 17,000 lbs to start (a small amount of the total capacity of the CWT). Even with the "fix" of having 17,000 lbs of fuel in the CWT, there's a LOT of vapor still remaining. Doesn't seem anything at all has been fixed, does it? This is because there was never a need for a fix. The aircraft was hit with a missile.

To prevent dry-running.


No, this is not at all the case. In fact, the provision to stop using fuel via the primary jettison/override pumps when the fuel quantity reaches 3,000 lbs. belies your point. One simply stops transferring at 3,000 lbs using the jettison/override pumps,and finishes the last 3,000 lbs using the scavenge pumps (or one stops using the jettison/override pumps in the CWT when either pump low pressure light illuminates). It's important to understand that the CWT primary fuel pumps, the jettison/override pumps, don't empty the tank anyway...depending on the airplane, they'll drain it down to 2,600 to 4,000 lbs, and that's it. After that, the remaining must always be removed with the scavenge pump.

When 17,000 lbs of fuel are in the CWT, there's still plenty of vapor, to go around. My statement was correct.

Now...if there is really an explosion hazard in the CWT...isn't it remarkable that TWA 800 is the only one to have exploded out of hundreds of thousands of operating hours, and isn't it remarkable that it occurred in an aircraft not using CWT fuel, in which the ignition source wasn't energized, and isn't it particularly remarkable that if indeed this explosion hazard does exist, nothing has been done to fix it save for carrying a little fuel when the pumps are to be turned on? Not much of a fix for such a deadly threat.

The problem is, the problem didn't exist; TWA 800 didn't simply explode, pack heating not withstanding. it was shot down.

You don't seem to realise it's fuel vapour which ignites, not liquid fuel. No oxygen, no fire.


You don't seem to realize that although I fly professionally and have spent many years as a professional "engineer" (mechanic), I've spent a number of years as a professional firefighter...and yes, I really do understand that vapor ignites. You may not understand that fuel vaporizes rapidly, and with a breach of a tank and the admission of oxygen, there is indeed a fire. TWA 800 was shot down.

[TURIN]

You don't seem to realize that although I fly professionally and have spent many years as a professional "engineer" (mechanic), I've spent a number of years as a professional firefighter..

How many years have you spent checking your 'facts'?


At least two 737s have exploded on the ramp when cwt fuel vapour has exploded after prolonged and intense use of air con packs on the ground.

[hawker man]

http://www.caasd.org/atsrac/FAA_PI-Engineer_Workshop/2002/SFAR-88-Related-Operating-Rules-and-Special-lMaintenance-Requirements.pdf

SNS3GUPPY

Have a look at the link above i think you will find a few Aircraft have had fuel tank explosions either on the ground or in the air. Also look at all the trouble EASA have gone to just to reduce the risk.
http://www.easa.eu.int/ws_prod/g/doc/Agency_Mesures/Agency_Decisions/2007/R/2007-002-R%20Fuel%20Tank%20Safety%20Part-145.pdf

You will also find that every maintenance manual for Aircraft that fall into the catergory of this requirement has a warning on every maintenance task that it is considered CDCCL (critical design configeration control limitations) so a lot time and money has been spent on this and you say the problem does not exist. If you have access to a maintenance manual of a Boeing or Airbus take a look and you will see what I mean.

[violator]

Guppy,

Packs cause heat, and were most likely the heat source for the missile. Packs do not "cook up" the fuel, nor do the packs use up the fuel, nor has heating of center wing tank fuel by proximity of the packs been responsible for a CWT exploding. Accordingly, my statement was correct.

No one said that the packs use fuel or a designed to heat the tank, nevertheless they clearly do heat the tank and the fuel. Heat from the packs can quite easily raise the temperature of the centre tank above the LFL.

The capacitance probes did not, do not, and have not represented an ignition source, and are a passive source of fuel sampling (as opposed to float gauges or another electromechanical source). Accordingly, my statement was correct.

To the first point, cap probs can be ignition sources in two ways. Firstly, if they are poorly bonded a lightning strike can cause arcing. Secondly, they provide (through their harnesses) a route for high energy to enter the tanks.

They are clearly active! A potential difference is applied to them, a current flows. Simply because other in-tank components may work differently doesn't make them any less active.

A missile strike in proximity to the fuel tanks would have caused plastic deformation of the fuel cell (which it did), and most likely expansive deformation of the wing tanks as well (which it did). Aside from the plastic deformation, rupture of the tank occurred, meaning that as fuel exits the cell, and vapor, the presence of nitrogen in the cell is irrelevant; it's going to burn and explode anyway

But your original comment suggested that an inert ullage wouldn't have helped TWA800 had there been an ignition source in fuel because you implied that inert ullage wouldn't have prevented the liquid fuel from exploding. You used your point to try and show how fuel tank inerting systems are useless.

Nitrogen in the tank will suppress arcing from a contained ignition source, but this wasn't the case.


You're in no position to state what the case was or wasn't.

However, you're responding to a statement that the CWT wasn't used, and not being used, the alleged ignition source, the fuel transfer pump, was deactivated and also not in use...meaning the source claimed to have triggered the explosion wasn't active or energized.

Firstly, there is nothing preventing dry-running of 747-100 fuel pumps. Secondly, the FQIS was implicated, which (as we've established) is an energy source, is active and has no intrinsic safety barrier.


A tank which is vapor doesn't necessarily burn or explode until a combustible mixture is reached, and thus the notion that simply because the tank does not contain fuel makes it likely to explode is in error

No one said that. At the same temperature an empty tank full of vapour is a worse than a non-empty tank with the same vapour.

oreover, currently the 747 continues to fly with empty center wing tanks, and the only requirement to address this matter is that if any fuel is to be used from the tank, it have 17,000 lbs to start (a small amount of the total capacity of the CWT). Even with the "fix" of having 17,000 lbs of fuel in the CWT, there's a LOT of vapor still remaining. Doesn't seem anything at all has been fixed, does it?

This is due to two things. Firstly, SFAR88 should have eliminated any energy sources (such as short-circuiting in FQIS wire bundles). Secondly, the fuel level is to prevent pump dry-running, which is another potential energy source.

However, ignoring your attempt to make this point support your idea that TWA800 was shot down, it is relatively valid. 747 Classics don't have intrisically safe fuel systems and the 747 Classic FQIS still has 1e-6 pfh chance of introducing a high energy source (resulting in a catastrophic case). It wouldn't be certified today.

The aircraft was hit with a missile.

You've said nothing to support that theory. It's OK having an outlandish theory, but you have to provide some evidence. You haven't done that yet.

No, this is not at all the case. In fact, the provision to stop using fuel via the primary jettison/override pumps when the fuel quantity reaches 3,000 lbs. belies your point. One simply stops transferring at 3,000 lbs using the jettison/override pumps,and finishes the last 3,000 lbs using the scavenge pumps (or one stops using the jettison/override pumps in the CWT when either pump low pressure light illuminates). It's important to understand that the CWT primary fuel pumps, the jettison/override pumps, don't empty the tank anyway...depending on the airplane, they'll drain it down to 2,600 to 4,000 lbs, and that's it. After that, the remaining must always be removed with the scavenge pump.

When 17,000 lbs of fuel are in the CWT, there's still plenty of vapor, to go around.

I don't understand your points: 17 klbs of fuel in the CWT ensures that all pumps are covered and ensures that no dry-running can occur. It's not designed to reduce the amount of vapour in the tank, it's designed to mitigate ignition risks (dry-running fuel pumps).

Now...if there is really an explosion hazard in the CWT...isn't it remarkable that TWA 800 is the only one to have exploded out of hundreds of thousands of operating hours, and isn't it remarkable that it occurred in an aircraft not using CWT fuel, in which the ignition source wasn't energized, and isn't it particularly remarkable that if indeed this explosion hazard does exist, nothing has been done to fix it save for carrying a little fuel when the pumps are to be turned on?[/quote[

That low frequency of 747 fuel tank explosions isn't surprising, it's to be expected. Boeing calculated it to be a 1e06 pfh event, they have occured at about that rate.

'Not using CWT fuel' implies large ullage, which as we've discussed is the worst case.

The FQIS were indeed energised, they are active components. There is no intrinsic safety on FQIS harnesses. There is nothing to automatically prevent pumps dry-running - there are obvious ignition sources.

Ensuring there is 17 klbs of fuel in the CWT prevents the pumps dry-running, SFAR88 ensures the FQIS doesn't introduce ignition sources. 747 Classics are dinosaurs with few flying, as usual cost overrides safety, which is why few (if any) will be fitted with a fuel tank inerting system. 787 and A350 will have full fuel tank inerting systems.

[quote] You don't seem to realize that although I fly professionally and have spent many years as a professional "engineer" (mechanic

That seems to be the problem, you're a pilot not an engineer. Your entire theory is bad science. You use a little knowledge to try and cement a poorly-thought through theory that cannot be tested. You erroneously use vague examples to support your ideas. You ignore evidence that doesn't support your ideas.

[cessnapuppy]

this is taking on the characteristics not of a reasoned debate but of religious proselytizing. There will be no 'convincing' done here as the facts are convincing in and of themselves. All not convinced wont ever be.

[TURIN]

Good though, innit?:D

[Peter Fanelli]

TWA 800 was not shot down by a missile, it was brought down by a meteorite.
Picture such an object entering the earth atmosphere just over the horizon from the perspective of someone on the beach of Long Island and there you have your flaming object apparently rising from the surface and striking the aircraft. By the time it got to the aircraft it may have been quite small but still hot enough to have provided an ignition source and now it's just laying on the ocean floor looking a lot like any other rock.

That's my belief anyway, ever since I had a close encounter with a meteorite myself while flying early one morning in Australia. And I don't mind telling you it scared the crap out of me at first.

Flame away.

:ooh:

[SNS3Guppy]

That seems to be the problem, you're a pilot not an engineer.


Come again? I am an engineer. I believe I made that clear.

I am also a pilot.

I also happen to have had a number of years professional experience as a firefighter, as previously mentioned.

MITRE CAASD || File not found (http://www.caasd.org/atsrac/FAA_PI-E...quirements.pdf)



This report addresses 17 cases of fuel tank explosions, 3 of which are of unknown origin. Four were from wing fires, of which TWA 800 is not implicated. Four were electrostatics, also not relevant according to the official report which blames wiring, or the official fix, which blames the pump. 2 were lightening strikes, which was not the case for TWA 800, and are irrelevant. 2 claim pumps or wiring related to the cause...that's two out of seventeen. One was a small bomb...if we're to believe that it was wiring or a pump, we can discount the bomb incident. 1 was maintenance action. What this leaves of the 17 cited fuel tank explosions is only two that are relevant, and three unknowns. So much for the 17.

HOWEVER...12 hull losses are cited for military aircraft, consisting of B52 and B707 airframes...and every single one occurred with cut fuels, specifically JP4. No cases of explosions using only jet fuel...all had gasoline in the mix.

On the civil side is a B707 in Maryland, fueld with JP4. A DC8 in Toronto, using JP4. The Iranian 747 previously identified, and using, of course, JP4. A b727 is cited as having exploded while using Jet A, but of course it was destroyed by a bomb.

A 737 in Manilla is cited for unknown causes, and was using Jet A. TWA 800 is cited...but involves conjecture as to the ignition source. A B737 in Bangkok exploded, this time with Jet A1, but no known ignition source.

Nearly every case of an explosion involved Gasoline cut fuels (as has been the case with every recorded in-flight explosion following a lightening strike...go figure), and the few that didn't were either a bomb, or can't be identified.

What this really means is there's no evidence of any significance in that report of aircraft with Jet A in the tank exploding due to a CWT heated by packs, with faulty wiring. In fact, there's no evidence. Baseless conjecture, at best.

What's the common thread among nearly all the mishaps given? JP4. The remainder involve unidentified ignition sources and one identified bomb.

TWA 800 wasn't using JP4.

You're in no position to state what the case was or wasn't.



Nobody is. However, it's irrelevant, as TWA 800 was shot down.

At the same temperature an empty tank full of vapour is a worse than a non-empty tank with the same vapour.


Actually that's not true, particularly if there's an explosion and the tank is breached. The additional volume of the empty tank occupied by the small extra amount of vapor mixture won't contribute nearly as significantly to the explosion and conflagration as a partially full tank will after rupture; the partial fuel load then vaporizes and adds immensely to the energy of the explosion and the ensuing fire.

However, unless either situation reaches a combustible mixture, the quantity of fuel in the tank is irrelevant with respect to an explosion.

Firstly, there is nothing preventing dry-running of 747-100 fuel pumps. Secondly, the FQIS was implicated, which (as we've established) is an energy source, is active and has no intrinsic safety barrier.


Well yes, actually, there is...firstly a flight engineer who turns off the CWT pumps and sees a bright amber low pressure light telling him to do so, and secondly...while the FQIS was "implicated," this has occurred with little more than ancillary "evidence."

You've said nothing to support that theory.


Well, of course, there are witness reports. A few documented here, among the hundreds of reports which saw the missile leave the surface, streak upward, and the saw the explosion...

TWA Flight 800: EYEWITNESS STATEMENTS TO POLICE (http://whatreallyhappened.com/RANCHO/CRASH/TWA/WIT/wit.html)
TWA Flight 800: STATEMENTS BY EYEWITNESSES (http://whatreallyhappened.com/RANCHO/CRASH/TWA/STATEMENTS.html)
The Flight 800 Investigation (http://www.twa800.com/eyewitnesses.htm)
TWA Flight 800 Eyewitness Quotes (http://www.flight800.org/eye2.html)
Witness sketches get no sunlight at 'Sunshine Hearing' (http://www.flight800.org/sketch.htm)
Review of the Official TWA Flight 800Witness Reports (http://www.flight800.org/witness-review.htm)
TWA Flight 800 Eyewitness Evidence (http://www.flight800.org/eye.html)
Sketch located by independent researcher (http://flight800.org/levine.htm)
The Flight 800 Investigation (http://twa800.com/pages/wit649_debunks.htm)
http://twa800.com/witnesscd/Witness649.pdf

Relevant data from the Eyewitness Group Factual Report:

* Based on the data, 183 witnesses said they saw a streak of light, 201 said they saw one or more explosions, 100 said they heard one or more explosions, and 339 said they saw a fireball.
* Of the 183 who observed a streak of light, 102 gave information about the origin of the streak. Six said the streak originated from the air, and 96 said that it originated from the surface. Of the 96 who said it originated from the surface, 40 said it originated from the sea and 10 said it originated from land.
*One hundred and twenty-eight witnesses reported an immediate end to the streak, 85 described it ending in an explosion, 32 said it ended in a fireball, and 11 said it ended in a flash.



Several reports, very rapidly suppressed, identified traces of explosive residue among the wreckage, as well as input on trajectories and potentials. For example:
Flight 800 Petition: Section 3 (http://www.flight800.org/petition/pet_sect3.htm)
Flight 800 Petition: Section 2 (http://www.flight800.org/petition/pet_sect2.htm)
Flight 800 Petition: Section 1 (http://www.flight800.org/petition/pet_sect1.htm)
The Flight 800 Investigation (http://www.twa800.com/smoking-gun.htm)

There's that pesky nagging fact that it's never happened before, and it couldn't be duplicated, even by the investigators...

As late as March 15, 1997 NTSB was having difficulty proving the theory they had settled on months earlier. From a Newsday article: TWA Tests Inconclusive Attempt to ignite fuel fails. From the article:

" FEDERAL AIR-CRASH investigators, testing theories about mechanical failures that could have ignited the center fuel tank of TWA Flight 800, have managed to produce a buildup of static electricity on two parts from a similar 747's tank by spraying them with jet fuel. But so far the voltage has been insufficient to ignite fuel vapors, sources in the investigation said, making the tests inconclusive. The tests, conducted at Wright Patterson Air Force Base in Ohio, are part of the National Transportation Safety Board's increasingly complex effort to explore possible mechanical causes for the Flight 800 disaster.

Investigators have produced low levels of voltage through the experiments, but not enough to create a spark, a safety-board source said. The tests are being conducted under various conditions of temperature and humidity.

One aerospace engineer expressed doubt [that] a static discharge could have created a spark powerful enough to ignite vapors in the center fuel tank, particularly in the thinner air at 13,700 feet.

``The question is, how could a little spark make this thing go bang,'' said Paul Czysz, a St. Louis University aerospace engineering professor. ``Even if it discharged, is there enough energy in that discharge to cause the fuel air mixture to burn? And if it does burn, is there enough concentration of the burning to heat the air temperature high enough that you get a detonation wave?''


Now, of course, to explain themselves, the NTSB did in fact show a video of a CWT exploding (Explosion Dynamics Laboratory), implying that they were able to create a similiar situation. It was a 1/4 scale model, and they didn't simply use kerosine, but pumped hydrogen into their model, and propane, before setting it off...and they weren't able to achieve ignition through any combination of jet fuel and FQIS or pump useage. They used a dedicated ignition device, because it was the only way they could get the explosion to put on film. Still, the visual of a *simulated* CWT exploding is very emotionally moving...just a lie. What it really amounted to was little more than a "mythbusters" exercise, and was far from scientific.

Let's ignore the fact that the NTSB was never able to establish, let alone prove that an explosive fuel mixture existed in the CWT, and take it on faith that there was such a mixture present. Set aside that a competent FE missed two pumps on, and ignored the amber low fuel (indicating low fuel pressure from those pumps) lights. Ignore the lack of evidence of any ignition source. Let's ignore the hundreds of witnesses who saw a streak of light originate at the surface, and proceed to the aircraft where they saw an explosion. Let's ignore the fact that even the military ballistics report claims being inconclusive and not having adequte information, or that it was part of the government documentation (much of which changed from the early statements and reports, to it's final itineration). Let's ignore that such an event has never occurred before, or that the substantiation from reports such as the previously cited SFAR88 document can only cite irrelevant events using different fuel and circumstances, and that the report lumps in bombs, lightening strikes, and unknown causes in an attempt to link them to the TWA800 event. Let's ignore the witness drawings, the witnesses not allowed to testify, the evidence which was *misplaced,* and the recanted testimonies from some notable and authoritative sources (including weapons experts at China Lake). What we're really left with is a coverup of a shootdown of TWA 800.

[leewan]

TWA 800 was not shot down by a missile, it was brought down by a meteorite.

For a moment, I thought that was a sarcastic comment.:) ( Is it ?)
It must be very, very unlucky to be hit by one as the statistics would be exponentially great.

[TURIN]

Based on the data, 183 witnesses said they saw a streak of light, 201 said they saw one or more explosions, 100 said they heard one or more explosions, and 339 said they saw a fireball.
* Of the 183 who observed a streak of light, 102 gave information about the origin of the streak. Six said the streak originated from the air, and 96 said that it originated from the surface. Of the 96 who said it originated from the surface, 40 said it originated from the sea and 10 said it originated from land.
*One hundred and twenty-eight witnesses reported an immediate end to the streak, 85 described it ending in an explosion, 32 said it ended in a fireball, and 11 said it ended in a flash.

So, out of 183 "witnesses", and of the 102 who gave info, less that half say the missile came from the sea and less than 10 % say it came from land.

Where did the others think it came from? Little green men?

Eye witness reports are notoriously bad.

I "witnessed" a mid air collision between a hang-glider and paraglider many years ago and I could have sworn blind that I heard a shotgun go off. "They were being shot at" the conspiracy theorists would say.
What I heard was the hang-gliders leading edge tube (main spar) snap in half at the time of impact.

Eye witnesses prove very little but often add to confusion and stoke up improbable theories for those with an axe to grind.

I will not accept half baked beliefs against hard evidence. The aviation industry has spent millions introducing inerting systems and altered maintenance practices, not to mention redesigning fuel systems to comply with more recent regulation.

You (and others) say all this has been done to cover up a crime?

Nope.

[Cusco]

Well, guys: I'm beginning to regret having started this thread.

However thanks to all of your helpful links I now understand the principle and practice of 'inerting' fuel tanks on passenger jets and for that I'm very grateful.

I don't frequent PPRuNe very often and the main reason is the kind of stuff which has littered the rest of this thread culminating in the inevitable PPRuNe style name calling and sh*t throwing.

I have read the conspiracy theories with some interest and will leave you all to argue the toss.

Usually, when views are so entrenched in different sides of an argument no resolution or agreement ever ensues: It looks as if that's the way this thread is going.

Cheers

Cusco

[Peter Fanelli]

For a moment, I thought that was a sarcastic comment.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif ( Is it ?)
It must be very, very unlucky to be hit by one as the statistics would be exponentially great.
Nope, no sarcasm at all.
It never occurred to me that it could have been a meteorite until two things happened to me. The first was as I stated in my post my own close encounter with a meteorite while in flight at night.
The second was a few years ago I was driving to work at BWI and the traffic report was on and suddenly the reporter went crazy about what he was seeing in the sky. It was later revealed that a satellite had fallen out of orbit and re-entered the atmosphere that morning. The surprise for me was when I turned into the airport and could see the smoke trail for myself I was surprised that it was not close to vertical from sky to ground but almost horizontal and in fact from my point of view appeared to gain altitude as it burned up.
Thinking about the experience that day I came to the conclusion that maybe the "missile" that was reported striking TWA800 was in fact a meteorite.

If I'm wrong I'm wrong, but in the absence of any other firm evidence I'm prepared to believe it.


It must be very, very unlucky to be hit by one as the statistics would be exponentially great.


Would you like to hear about the time I ran into a screw in flight?

[subsonic69]

pls elaborate... im interested ( not being sarcastic in anyway )...

[cessnapuppy]

pls elaborate... im interested ( not being sarcastic in anyway )...
Me neither - this guy is a **** magnet...stay away!! LOL*

If I'm wrong I'm wrong, but in the absence of any other firm evidence I'm prepared to believe it.

That 'firm evidence' wouldnt include Viagra by any chance, would it??? ROFL








*A loose screw in the sky finds its way to you: not impossible, airlines dont just 'fly about in the sky' but travel on well defined 'air highways' so while that does narrow the available area for **** to be in, I dont get why this screw will hang around till you got there.

Did you keep the screw? Maybe connect it to any other flights in your area during that time frame?

[violator]

Come again? I am an engineer. I believe I made that clear.

I am also a pilot

You said:

I fly professionally and have spent many years as a professional "engineer" (mechanic)

So are you a mechanic, an "engineer" or an engineer? A mechanic is not an engineer.


Quote:
You're in no position to state what the case was or wasn't.

Nobody is

I think the NTSB are in a better position than any of us. But regardless of that, I'm glad you've accepted that you cannot rationally say that a missile hit TWA800.

Well yes, actually, there is...firstly a flight engineer who turns off the CWT pumps and sees a bright amber low pressure light telling him to do so, and secondly

A flight crew member acting correctly is maybe a 1e-6 pfh function, which is approx 1e-5 over a flight. A light bulb is about a 1e-5 pfh function. <1e-5 pfh doesn't support any case worse than a major safety case - dry-running of pumps in tanks is now a catastrophic safety case. This is the reason why older types have had automatic centre tank pump shut off retrofitted (737NG) and why centre tank minimum fuel procedures have been adopted.

secondly...while the FQIS was "implicated," this has occurred with little more than ancillary "evidence."

I'm glad you've accepted that FQIS was implicated. And as we've discussed on the 747-100 there is no intrinsic safety barrier preventing high energy from entering the tank through the FQIS harnessses.

Actually that's not true, particularly if there's an explosion and the tank is breached.

I didn't talk about a tank rupture, I talked about the explosion risk. A tank full of vapour and empty of fuel is a worse case than a tank not empty of fuel. More component failures may result an explosion, potential across more structure has the capability to arc.

The additional volume of the empty tank occupied by the small extra amount of vapor mixture won't contribute nearly as significantly to the explosion and conflagration as a partially full tank will after rupture; the partial fuel load then vaporizes and adds immensely to the energy of the explosion and the ensuing fire.

I really don't understand this point, you haven't shown that a missile hit TWA800 and there's no evidence that the tank was ruptured from the outside. The contribution of a full or not-full tank to a missile explosion is irrelevent until you've established there was a missile.

Let's ignore the fact that the NTSB was never able to establish, let alone prove that an explosive fuel mixture existed in the CWT, and take it on faith that there was such a mixture present. Set aside that a competent FE missed two pumps on, and ignored the amber low fuel (indicating low fuel pressure from those pumps) lights. Ignore the lack of evidence of any ignition source. Let's ignore the hundreds of witnesses who saw a streak of light originate at the surface, and proceed to the aircraft where they saw an explosion. Let's ignore the fact that even the military ballistics report claims being inconclusive and not having adequte information, or that it was part of the government documentation (much of which changed from the early statements and reports, to it's final itineration). Let's ignore that such an event has never occurred before, or that the substantiation from reports such as the previously cited SFAR88 document can only cite irrelevant events using different fuel and circumstances, and that the report lumps in bombs, lightening strikes, and unknown causes in an attempt to link them to the TWA800 event. Let's ignore the witness drawings, the witnesses not allowed to testify, the evidence which was *misplaced,* and the recanted testimonies from some notable and authoritative sources (including weapons experts at China Lake). What we're really left with is a coverup of a shootdown of TWA 800.

Neither the NTSB nor anyone can prove a theory. Vapour in the tanks was clearly above the lower flammability limit, it had the capability to support combustion. The temperature in the tank was 38-52 deg C. The lower flammability limit of Jet A was 35.8 deg C.

Dry-running fuel pumps was not necessarily the source of ignition, but the pumps rely on pressure switches, harnesses, light bulbs and a fallible human to shut them off. As Boeing themselves have documented, it's well above 1e-9 per flight hour.

FQIS is a potential ignition source.

TURIN has helpfully discussed the witnesses.

Now let's consider the facts: Boeing themselves have submitted systems fault tree analysis that shows that the probability of 747-100 FQIS introducing high energy into the tank is 1e-6 pfh. It needs to be 1e-9 fh. This alone is compelling evidence that the 747-100 was an unsafe, flawed design and that it was only a matter of time before a centre fuel tank explosion occured.

Idon't frequent PPRuNe very often and the main reason is the kind of stuff which has littered the rest of this thread culminating in the inevitable PPRuNe style name calling and sh*t throwing.

What name-calling? This is a technical debate, what's wrong with it?

[SNS3Guppy]

So are you a mechanic, an "engineer" or an engineer? A mechanic is not an engineer.



You may be getting wrapped around the axle with UK terminology and use of the term "engineer" and "mechanic."

But regardless of that, I'm glad you've accepted that you cannot rationally say that a missile hit TWA800.


I said no such thing. There is no question that TWA 800 was shot down and the matter covered up. There is great ambiguity in the NTSB report and the information contained therein, as well as other agency input, the exclusion of significant amounts of testimony, the recanting of testimony, public exclusion, and many other details surrounding the case which are far from typical of an NTSB investigation. I can rationally say that TWA 800 was shot down and the matter covered up. The NTSB cannot rationally say that the CWT exploded from the FQIS or a fuel pump or caused the mishap.

I'm glad you've accepted that FQIS was implicated. And as we've discussed on the 747-100 there is no intrinsic safety barrier preventing high energy from entering the tank through the FQIS harnessses.


You misunderstood.

The FQIS was "implicated" in that it was alleged to have been a source of ignition, with no proof whatsoever beyond an allegation. Moreover, the NTSB and contracted specialist parties were 100% unable to duplicate a scenario in which this could possibly have happened. It's never happened before, there's no proof that it's happened before, and when they put on their little demonstration for the cameras, the simulation in a specially built tank with a specially built ignition source (not found in the aircraft) failed 100%...until they filled the tank with hydrogen and propane...also not found in the tank. In other words...their efforts to duplicate the explosion in any way, shape, or form...failed.

I didn't talk about a tank rupture, I talked about the explosion risk.


Which is entirely dependent upon a combustible mixture being present in the tank. The presence of vapor doesn't guarantee an explosive mixture. The tank was ruptured, however, and caused deformation of the adjacent inboard wing tanks, as well.

The contribution of a full or not-full tank to a missile explosion is irrelevent until you've established there was a missile.


As it is until one has established the contribution of an ignition source...which hasn't happened, either. There have been 26 shootdowns of commercial aircraft with surface to air man portable missiles...but no fuel tank explosions using Jet A which can be pointed directly to either the fuel pump or the FQIS...and there's nothing available to which the NTSB or any other party can point, that shows the FQIS or pump(s) or associated wiring as implicit in the event, save for allegations without foundation or evidence.

On the other hand, although stripped from the reports and excluded from the opportunity to testify, hundreds of witnesses saw a missile leave the surface arc upward, and strike the aircraft, followed by an explosion. Nobody saw any arcing in the fuel tank.

FQIS is a potential ignition source.


As is a missile.

Me neither - this guy is a **** magnet...stay away!! LOL*

That 'firm evidence' wouldnt include Viagra by any chance, would it??? ROFL


Well...we've certainly attracted a professional to the discussion. Thanks for the contribution. One can only wonder what nuggets of brilliance might emerge if the poster were older than say, 14 years of age.

So, out of 183 "witnesses", and of the 102 who gave info, less that half say the missile came from the sea and less than 10 % say it came from land.

Where did the others think it came from? Little green men?

Eye witness reports are notoriously bad.


Eye witness reports notoriously conflict, they are not necessarily "bad." The conflict is critical to understanding perspective, and the reasons they conflict often give valuable insight into what has taken place. What's different is just as important as what is the same.

There weren't simply 180 witneses...there were hundreds, on the order of nearly 800, who saw the event. These witnesses were not in the same location, and did not see it from the same vantage point, or necessarily see it at the same beginning moment or ending moment. One may fully expect that what they saw will be relayed in differing terms. What is interesting about many of the witness statements, however, is that their comments, and in fact their drawings illustrating what they saw, portray the first sighting of the event as originating at the surface...not in flight. Moreover, the witnesses included pilots (commercial and military), professionals, and others with a unique perspective on the matter.

Witness reports were quickly dismissed by investigators as these were very damaging to the case being built. The government worked very hard to cover up what had happened and to build an alternate theory...any alternate theory, while grasping at straws. Even the CIA video produced kept flashing on the screen "Not a Missile" to reinforce the concept that it wasn't a missile. Anything but a missile...and the FQIS and fuel pump wiring would have to do..even in the absence of any proof. Or ancillary evidence. Or evidence of any kind.

You (and others) say all this has been done to cover up a crime?


You (and others) would be best to put words in your own mouth, and not mine. I didn't say that.

Cover up yes. Cover up a crime? That would depend on perspective. Is it a crime that so many people died? Yes. Is it a crime that the truth was withheld? yes. At a time when the US government did not want the US to be seen as vulnerable to a terrorist act, it was very much in their interest to paint the event as anything but. However, this was a precursor which lead to the attacks on 09/11...terrorists who found that even a major public event such as the shootdown of TWA 800 could be covered up knew that they needed to do something so grandiose and so public that there was no way it could be hidden...which occurred with the events of 09/11.

No such thing as inerting systems, tosh.


No one, other than you, has suggested any such thing.

Not just the Uk this is a EASA requirement but only for the Engineers who certify on the Aircraft that meet the 7500 pound or 30 passengers or more.


Whether it be the UK, CAA, or EASA at large, this is still not "all." Just EASA.

[violator]

You may be getting wrapped around the axle with UK terminology and use of the term "engineer" and "mechanic."

Do you have an engineer degree? Are you chartered?

The NTSB cannot rationally say that the CWT exploded from the FQIS or a fuel pump or caused the mishap.

There's more evidence of an FQIS flaw allowing the CWT to explode than there is a missile, therefore your argument is less rational than the one you scorn.


The FQIS was "implicated" in that it was alleged to have been a source of ignition, with no proof whatsoever beyond an allegation

Here your lack of scientific training lets you down, you cannot prove a theory. There is however clear evidence that 747-100 FQIS is an ignition source, from Boeing's own mouth indeed.

Which is entirely dependent upon a combustible mixture being present in the tank. The presence of vapor doesn't guarantee an explosive mixture.

But the mixture was flammable. CWT temperature was between 38 and 52 deg C. The lower flammability limit of Jet A was 35.8 deg C.

.but no fuel tank explosions using Jet A which can be pointed directly to either the fuel pump or the FQIS...and there's nothing available to which the NTSB or any other party can point, that shows the FQIS or pump(s) or associated wiring as implicit in the event, save for allegations without foundation or evidence.

When Boeing themselves state that the FQIS is an ignition risk with a failure rate higher than required to get certified today and that the pump can dry run at a failure rate that is higher than required to get certified today then I suggest that there is clear evidence.


Quote:
FQIS is a potential ignition source.
As is a missile.

As is a dragon! Which has the same level of evidence as your missile.

One can only wonder what nuggets of brilliance might emerge if the poster were older than say, 14 years of age.

You don't know my age, nor would it make any difference. You're repeatedly made statements which are bad science, ignored rebuttles and twisted facts. Despite your age you don't seem to have a firm grasp of systems engineering.

[SNS3Guppy]

You don't know my age, nor would it make any difference.


No, I don't know your age, and before you get your dander up, you may wish to go back and re-read the quote to which you're replying. It wasn't made to you. You'll note I didn't quote you...I quoted another poster, and it was that poster (cessnapuppy) to whom I responded. In my post, I responded to three different posters...you're in a bit too much rush to take offense and argue, and not in any rush to read or comprehend that which is written.

The poster who made statements such as "Me neither - this guy is a **** magnet...stay away!!" did not do so in a professional, or adult manner, and it was him or her to whom I responded.

Your comments thus far, for the most part, have been more professional, albeit somewhat condescending.

There is however clear evidence that 747-100 FQIS is an ignition source, from Boeing's own mouth indeed.


No evidence. Ancillary allegations without physical evidence, and an inability to recreate the conditions or the event, do not "evidence" make.

From the NTSB's own "mouth" too, as well as that of the FBI, the CIA, and many other letter-based organizations. This provides an appearance of credibility, which was always the intent of covering the actual fact.

Here your lack of scientific training lets you down, you cannot prove a theory.


Of course not. Then it wouldn't be theory. However, the notion that TWA 800 was brought down by a failure of wiring in the fuel quantity information system or the fuel pumps is not a theory; it's a very shaky hypothesis. Experimentation attempting to duplicate or recreate the situaiton failed, and there was never any physical evidence to back up that hypothesis. Accordingly, the story that the FQIS was at fault will never rise to the level of theory.

You really have no idea what kind of "training" I've received, what degree or accolade I might hold, or my qualifications on any given topic...though it really doesn't matter. TWA 800 was still shot down, and my qualifications or expertise on this matter or that won't change that fact a whit.

But the mixture was flammable. CWT temperature was between 38 and 52 deg C. The lower flammability limit of Jet A was 35.8 deg C.


I stated that we do not know if the mixture was explosive. Flammability isn't simply a matter of temperature. As we discussed at the beginning of the thread, an inerted atmosphere isn't flammable. Neither is one in which the mixture isn't in a combustible range. Without regard to the temperature in the CWT, we cannot say that it was explosive, or in a combustible mixture range. When the NTSB contracted with the Explosion Dynamics Laboratory to recreate the event and actually cause an explosion in the CWT (specfically, the 1/4 scale replica CWT they built for the tests), they were unable. They failed to do it. They finally had to use propane and hydrogen and a dedicated ignition source, none of which were present or found in the actual CWT, to cause the explosion which ensued...meaning they failed 100% in their effort. The explosion they caused had no bearing and no relationship to the actual event, and given the dynamics of the gasses used, and the change in scale to the tank, can't even be said to replicate the overpressure or deformation of the actual CWT on a realistic comparitive basis.

In short, while the media bought it, the NTSB (et al) were off in la-la land when it came to any semblence of a credible, realistic effort at trying their hypothesis regarding a CWT explosion. That is, they utterly failed to make their case.

Of course, when it came to considering the truth, anything which might threaten their case was excluded or dismissed out of hand.

Given your false assertion that I've ignored rebuttles (I didn't; I quashed them), used "bad science" (really?), and twisted facts (I provided them, and links, though you've been loath to address them), and your taking personal offense at comments made to others, suggests that further discussion will be without merit.

[galaxy flyer]

SNS3Guppy

While I usually like and respect your very good posts here, I have to disagree with your position. I cannot offer any technical information, just that for all these US agencies to "cover up" the shoot down of a commercial airliner requires LOTS of citizens and dedicated employees to compromise their ethical and professional standards. They would have to remain silent over a decade and during a time of war, a war created in your assertion by the very act of shooting down TW 800. I find all that hard to believe, despite lots of technical information and eyewitness testimony.

Shot Down? I still doubt it, not on the facts, but on the fact that conspiracies that big don't stay hidden. Might as well bring up the Grassy Knoll theory.

Lastly, you cannot state as fact it was shotdown, only that it is your opinion that it was.

GF

[SNS3Guppy]

I don't believe that many would be required to cover up a matte this large. Just enough to control the evidence and information. It was very tightly controlled, with some information never released, some not for two years, and even the salvage operation kept strictly under military control.

Operational security and compartmentalized access to certain information means it's not all that hard to control what's released and what wasn't. The strong propoganda effort dedicated to selling the concept that no missile was involved as overt and obvious. Even an amature magician would turn his head and cough at the poor misdirection offered by repeatedly telling the viewer "Not a Missile" on the animated production. The clear message? That they made their conclusion and publications not nearly so much to "explain" what had happened (they've never been able to do that, and can't, as long as the CWT wiring story remains the myth), but to divert attention from what really happened...TWA 800 was shot down.

[cessnapuppy]

However, this was a precursor which lead to the attacks on 09/11...terrorists who found that even a major public event such as the shootdown of TWA 800 could be covered up knew that they needed to do something so grandiose and so public that there was no way it could be hidden...which occurred with the events of 09/11

But 9/11 was an internal Govt plot to generate public opinion for the War!!

qWkWXBTsgsA

[Peter Fanelli]

*A loose screw in the sky finds its way to you: not impossible, airlines dont just 'fly about in the sky' but travel on well defined 'air highways' so while that does narrow the available area for **** to be in, I dont get why this screw will hang around till you got there.

Did you keep the screw? Maybe connect it to any other flights in your area during that time frame?







I had just blown my first instrument rating test and heading home when a hole appeared in the right side windshield(Seneca). It was assumed it had fallen from a Tobago also doing training at the same navaid above us. It wasn't until the windshield was repaired and the next pilot to fly it found a perfect impression of the screw in one of the right hand prop blades. Screw was not found in the cabin and is assumed to have bounced off and fallen into the sea, recovery not attempted.

[TURIN]

Quote:
No such thing as inerting systems, tosh.

No one, other than you, has suggested any such thing.


Quite right, my mistake. I misread an earlier post whilst under the influence.:O



After watching that Nat/Geo film I'm coming around to Mr Guppy's way of thinking. That piece of film is sooo bad it has to be fiction. ;)


However,

Quote:
You (and others) say all this has been done to cover up a crime?

You (and others) would be best to put words in your own mouth, and not mine. I didn't say that.

Cover up yes. Cover up a crime? That would depend on perspective.

Any sane individual would say that shooting down a civilian airliner is a crime, surely?

Even if it was an accidental shoot down it's still a crime. Isn't it?

TWA 800 was NOT shot down.

[galaxy flyer]

TURIN

Perhaps, not a crime, but an Act of War.

SNS3Guppy

Still skeptical. There have been, in my experience 5 transport category planes that have been hit by missiles, a C-5, a C-17, C-130, an A-300 and a HS 125. the the first four by SAMs of the type you speculate was used to shoot done TW 800, the HS 125 by two Atolls fired by a MiG over Africa. NONE were shot down to a hull loss. Admittedly, the Airbus was a close call with a wing fire; but the other three were easily landed. All five were shot in the heart of the missile's envelope; while the 747 was at the outer edges of the envelope. The C-5, despite having a fuel tank inerting system, was restricted to carrying stored fuel to keep its pumps submerged in the aftermath of the TW 800 event.

Based on the weak evidence of a shoot down and the numerous cases of transport category planes suffering fuel tank explosions, the probable case stands, legally and professionally. I know TWA vets can't stand the fact a 100,000 hour 747 might have been victim of old age, but it is a strong case.

I'd love more evidence, stand open to new evidence and still respect your opinions and postings as being authoritative and worthwhile. I just have a hard time with conspiracies.

GF

[SNS3Guppy]

Based on the weak evidence of a shoot down and the numerous cases of transport category planes suffering fuel tank explosions, the probable case stands, legally and professionally.


There's strong evidence of a shootdown, but no actual evidence of a fuel tank electrical problem causing an internal failure. Moreover, there have been no cases of fuel tank explosions on Jet A, as previously discussed, where the FQIS or pump wiring could be pinpointed as the cause. Previously in this thread we considered 17 separate fuel tank explosions...the majority on military aircraft using JP4 cut fuels...not Jet A. Refer to the previous thread.

There have been, in my experience 5 transport category planes that have been hit by missiles, a C-5, a C-17, C-130, an A-300 and a HS 125. the the first four by SAMs of the type you speculate was used to shoot done TW 800, the HS 125 by two Atolls fired by a MiG over Africa.


The C5 and C17 were manpads shots, both survivable, both landed safely following missile strikes.

I'm not sure that the aircraft shot down in air to air missions can be counted, as we're talking about an aircraft (TWA 800) shot down by a surface missile. If indeed you count civil transport aircraft shot down by surface missiles in total, there were 24 prior to the TWA 800 shootdown. A total of 35 civil aircraft had come under fire from missiles at that point, with 24 shot down, and 500 deaths. (A number more are likely to have been shootdowns, but aren't included due to inconclusive circumstances. This also disregards missile shots which missed).

An Ariana Afghan Airlines DC-10 was damaged by missile fire, but landed with no fatalities.

Two separate Angolan Airlines 737's were hit by surface missiles, a year apart. One was lost with all souls on board, and the other suffered no loss of life (though the aircraft was totaled).

A Congo Airlines 727 was shot down will all on board dead.

Air Rhodesia #825, a Vickers Viscount was shot down with a SA7. It burst into flames. Some survived.

Air Rhodesian #827, also a Vickers Viscount, was shot down by a Strela 2 missile, with no survivors.

Three Transair Georgia Tupolevs, TU134's and TU154's, were shot down by surface to air missiles, killing all aboard.

Lionair #602, an AN-24, was shot down with a man portable missile, with all on board lost.

Siberian Airlines 1812 was shot down by a SA5 missile, with all killed.

The European Air Transport A-300, hit by a SA14 approaching Bagdhad, has already been noted.

A Transaviaexport IL75 was shot down by a missile with the loss of all hands.

An AerianTur-M AN26 was shot down by a man portable missile, with the loss of all but one crewmember.

Two SA7's were fired at an Arkia Israeli Airlines 757 missed, with no fatalities.

In a 1996 New York Times article by John Kifner, an observation by Stephen Sloan is notable:

There are believed to be hundreds of the missiles unaccounted for since the war in Afghanistan.

Writing on the changing nature of terrorism in a publication of the United States Army War College last year, one expert, Stephen Sloan, warned: "A Stinger missile aimed at a jumbo jet as it takes off or as it approaches a large metropolitan airport could cause tremendous casualties."


Just a few weeks prior to the TWA 800 shootdown, a missile launch was filmed on a private camcorder by a local citizen in New York. That video was given to the FBI. An attack on Khobar Towers with the death of 19 US citizens also occurred around the same time, precursors to the TWA shootdown. The US also received credible warnings of the shootdown, and ignored them.

In 1994, the Maryland State Police found a French Mistral man portable missile, complete with launcher, ready for use. The weapons were available, in country, and had previously been launched. We were in a time period where it was very much in the national interest (and policy) to provide an atmosphere of safety. Even in the presence of a terrorist event which was unable to be stopped, denying recognition of the event and promoting a sense of security was very much at the top of the bill for the Administration and those associated with it.

A 2004 report before Congress from Congressional Research Service cites 12 of the 29 allied aircraft shot down during gulf war 1 as being MANPADs shots. For our own covert support mission in Afghanistan the first time around, the Mujahedin shot down 269 soviet aircraft using MANPADs. Of the 350,000 to 500,000 man portable missiles believed to be logged into military arsenals world wide, present estimates place between a ridiculous low and an overconfident high of 5,000 to 150,000 missiles in terrorist hands.

The shoot down of TWA 800 isn't a far-fetched conspiracy theory. It happened. The conspiracy is in the propaganda effort to divert attention to an untenable hypothesis...and given that the efforts to support that hypothesis (wiring) fell short in tests and experiments...it doesn't even merit the status of a theory. The idea that TWA 800 was victim to internal wiring was never more than a glossy high-priced cover story which did us all a disservice by not emphasizing the truth...that TWA 800 was shot down.

I know TWA vets can't stand the fact a 100,000 hour 747 might have been victim of old age, but it is a strong case.


I disagree. There's no strong case, and there's been no evidence--none--among all the other airframes examined. Not even in the wreckage itself, though the easy out is that it wouldn't be, given the nature of the mishap.

I'm no more hiding from the truth, or trying to pretend that old airplanes break, than anyone else. I've personally piloted two large aircraft which subsequently broke up in flight (not while I was on board). Both aircraft were considerably older than the 747-100 operating as TWA 800. I knew everyone on board, and I'd flown both aircraft. I did a type rating in one, and took my initial FE checkride in the other. Three other aircraft I've flown experienced completely fractured spars. I'm well aware of what can happen to aircraft and the potential for mechanical failures. (I experienced an explosive depressurization myself earlier this year, attributed to a cockpit windscreen failure, fatigue, and age of the aircraft and window assembly). I get it. Things fail. But not this time...TWA 800 was shot down.

[TURIN]

Crikey!

Your middle name isn't Jonah by any chance?:eek:

In the interests of balanced posting..

TWA 800 was not shot down. :ok:

[bvcu]

Dont suppose it will ever be proved to everybodies satisfaction what caused TWA800 loss , but the facts are that as a result of trying various theories for ignition sources a lot of problems were found in the operational fleet. A lot of wiring faults and anomalies were found in gauging systems as a result of the inspections/SB's we had to carry out as a result. Fuel pump failures that had the potential for being an ignition source resulted in c/b resets in flight being generally stopped on most types . I recall 2 B767 pump failures on a modified safer pump being the catalyst for this as well where bearing failures had the potential to be an ignition source. Cant believe the expensive new inerting system on current 777 deliveries is there just for show !!!

[muduckace]

Sat on a 100 deg ramp in old 741/2's all day, just about every day for years with packs running and why the first incident on T/O over the drink after allmost 30 years of no issues?

I press the bull**** button.

Not all aircraft are equipped with tank inerting systems, civilian aircraft have devices that Wiki quote:

It is a catalytically based system that converts the fuel vapor and oxygen to inert gas and water. The system can reduce the oxygen level down to well below 1.0%. Additionally, by reducing the fuel vapor as well, the system adds extra protection from fuel tank explosions.

I understand some military aircraft actually pump nitrogen into their tanks.

I think the systems are worthless unless you are getting shot at, the TWA-800 also drove repetative wire inspections for most aircraft, this is not a bad idea.

[muduckace]

Just speculation.

Do you seriously believe that if a government had the ability to cover up a terrorist attack that could have resulted in fears coming close to those of 9/11/01 that they would not do it. I know I shure as well would have.

Just the effect on the aviation industry would make it worth it not to mention delaying a "war on terror". Keep it covert. The clinton admin had been after binladen and friends just lacked the sack to hit them when they had the chance.

[galaxy flyer]

muduckace

No, I don't doubt that if they thought they could cover it up, they would. I doubt that they can keep a conspiracy to cover it up going. A lot of people with professional reputations to protect had to go along with the cover-up, guys like Jim Kallstrom.

SNS3Guppy

No doubt, strong assertions and strong record of shotdown transport category planes. It would have been a manpad used on TW 800 would still have been a lucky shot--in the dark simply finding the target and getting a tone would be lucky.

Think of what history might have been if a "shootdown" had been out in the open, Iraq 8 years earlier, war in Afghanistan, etc. If you assertions are true, it should be pursued HARD.

GF

[Pugilistic Animus]

This is really interesting I'm going to just sit and watch:suspect:

[SNS3Guppy]

If you assertions are true, it should be pursued HARD.


It is being pushed hard. Multiple law suits, and a lot of hard efforts by some well placed people and organizations with some very established backgrounds. It is, however, a very steep, uphill battle.

[Pugilistic Animus]

I also saw that 'zoom climb analysis' and Iadmit it was very intriguing.
this 'accident' alway left me with lots of suspicion wrt the cause,...now having someone like Guppy say what I'd always suspected makes it even harder to believe that fuel theory

[violator]

Sat on a 100 deg ramp in old 741/2's all day, just about every day for years with packs running and why the first incident on T/O over the drink after allmost 30 years of no issues?

I press the bull**** button.

This is by far the most ridiculous and ignorant point raised.

I've been on countless 737s, before the rudder mods, and none of them crashed. Ergo, no problem?

I've never been hit by a drink driver, stabbed or shot. I've never had a hospital-aquired infection. I've never been to Antarctica. Therefore none of those things exist!

The fact is that Boeing themselves have shown, through safety calculation, that the system is not as safe as it should be and the capability for high energy to enter the tanks can occur at a rate more frequent than required for certification. The basis of safety engineer is statistical, if you don't understand that I'd suggest staying away from these threads. Comments like 'it's never happened to me, therefore it doesn't happen' are simply embarassing.

[bcgallacher]

To my knowledge there have been at least 2 similar incidents to 737 aircraft - centre tank explosions for which there has never been a certain cause - only a probable. I was involved in a small way with the incident in the Philippines - the aircraft was only about a year old and the explosion took place at the end of pushback before engine start.The bottom of the tank was not ruptured but the top let go resulting in 6 fatalities in the cabin.I was informed by the investigating team that they found no traces of explosives.The scenario in both the incidents was the same - empty centre tank heated by pneumatic ducting.
As far as the 747 incident is concerned common sense suggests it would be impossible to cover up a missile attack - it would be obvious to even the least experienced investigator.

[superliner]

It has been really interesting following this thread, and as a neutral and vastly inexperience observer I have to say I've changed my belief more than once. Anyway, to satisfy my curiosity I read through the Wikipedia page for this accident. There is one thing that I think makes it difficult to believe is this:
There was nothing unusual on the Cockpit Voice Recorder (CVR) tape until 20:29:15 when the Captain stated: “Look at that crazy fuel flow indicator there on number four. . . see that?"

Now I acknowledge that I virtually don't have any knowledge about systems, but from that point on on the CVR it took about two minutes for the tape to stop recording. Is that too long a time for an aircraft that has been hit by a missile to survive?