FAA Fix For Fuel Tank Explosions
 

The Federal Aviation Administration said today that it hoped to propose a rule this fall that would require the airlines to cut the risk of fuel tank explosions like the one that destroyed T.W.A. Flight 800.

The rule would take effect in 2006, 10 years after the T.W.A. Boeing 747 crashed off Long Island, killing 230 people, and would have a seven-year phase-in period. It would cover about 3,800 big jets registered in the United States and built by Boeing and Airbus. The agency is in discussions with European regulators, but has reached no agreement with them


For years after they understood the broad outlines of the T.W.A. accident — ignition of the fuel tank by an electrical spark — regulators have discussed a variety of approaches. They talked about altering jet fuel so that it would be less prone to turn to vapor, the form in which it is flammable, or pumping inert nitrogen into the empty space in tanks when planes are on the ground. Both were rejected as too expensive.

But in December 2002, the F.A.A. demonstrated an onboard system that takes compressed air from the plane engines and uses it to remove some of the oxygen from ordinary air, thus raising the level of inert nitrogen, if only fractionally. That nitrogen is then pumped into the fuel tanks.

"We're taking this step because we have found a practical solution," the F.A.A. administrator, Marion C. Blakey, said. "Once planes are equipped with inerting technology, we can close the book on fuel tank explosions," she added. "It's a major moment in the safety of aviation."

The safety fix is also notable for the extent to which the agency used in-house engineering to figure out how to solve the problem.

Airlines could still oppose the F.A.A. solution, however, because of the costs. Installation would probably cost $140,000 to $220,000 per plane, officials said, plus another $14,000 annually for operating costs, which is high but not a record for the agency. And $14,000 would represent only a small fraction of the annual operating cost of an aircraft.

Depending on the size of the plane and its fuel tanks, the system will weigh 100 to 200 pounds, and will require some extra fuel use by the engines to provide compressed air, according to John Hickey, director of the F.A.A's aircraft certification service.

Boeing has said it will use inerting technology in its new 7E7, which is still being designed. The F.A.A. intends to require it on American-registered Airbus A-380's. A prototype of that plane is supposed to fly later this year.

Ms. Blakey, asked why some planes would not be equipped with a preventive system until 2013, or 17 years after the accident, said that the installation could only be done during major maintenance. But she pointed out that the F.A.A. had already issued scores of orders for inspecting or replacing wiring or other electrical components, to reduce the risk of tank explosions. The F.A.A.'s original strategy for guarding against fuel tank explosion was to exclude any possibility of spark, but Ms. Blakey said that with three fuel tank explosions in the last 14 years, the agency did not believe that that approach was reliable.

"We all know that one accident of this type, one accident of any type on board an aircraft, is simply one too many, both for the families of victims and for our airlines," she said. "Reducing commercial fatal accident rates is our No. 1 objective."

But she added that fuel-tank explosions were occurring at the rate of roughly one every five years, raising the possibility of another before a fix is installed.

Flight 800 was initially thought to have been downed by a bomb or a missile, and aviation engineers took some time to come to full recognition of the fuel tank problem. At the time of the explosion of Flight 800, when the Boeing 747 left Kennedy International Airport for Paris on a hot July evening in 1996, many experts believed that it would be difficult for the tanks to explode, because the fuel/air mixture had too much fuel or because the fuel was cold and would not readily turn to a vapor, the form that burns or explodes.

But extensive tests by the National Transportation Safety Board after the crash determined that the fuel/air mixture was often within the range that could sustain an explosion. In the case of Flight 800, the plane was delayed on the ground, with its air conditioners running, giving off their heat to the center fuel tank. As the fuel warmed, its propensity to turn to vapor increased.

Because the plane was not fully loaded and was making a relatively short flight for a 747 with the prevailing winds, it did not need to carry a full load of fuel. As a result, the ground crews had not filled the center tank; it had a few inches of fuel at the bottom, and a lot of air. As the plane climbed into thinner air, pressure in the tank dropped, allowing more fuel to vaporize.

The Safety Board said it could not identify the source of the spark, but examinations of the wreckage, and of other old 747's, found a variety of wiring problems.

One part of the above caught my eye ..."The F.A.A. intends to require it on American-registered Airbus A-380's".
Bloody yanks .... grrrr....
Seems they have no way of competing with massive sales for this wonderful a/c so they try to damage it in other ways.
( Not invented here syndrome again?)

Actually, since the FAA is concerned that this might be an issue, they want to protect the A-380, to make sure it will never suffer from such an accident.

See, you can slant it anyway you like. Not every thing the yanks do needs to be taken as a personal insult or be part of a larger conspiracy.

Great, now that we've earmarked all that $$$$ to save about one aircraft every seven years, the operators won't have the money to waste on unimportant stuff like CFIT system upgrades etc.

way to go public

Those pesky fuel tank explosions
 

"We're taking this step because we have found a practical solution."

A solution to what? What 747 ever suffered a fuel tank explosion *before* or *after* TWA800?

<<The Safety Board said it could not identify the source of the spark>>

The source of the spark was a frickin' SAM.

Man oh man. What a long way to go for a cover-up. And guess who foots the bill? Boeing and the airlines.

Brilliant. Kick 'em while they're down.

zerozero, poor sad person, said....

"<<The Safety Board said it could not identify the source of the spark>>

The source of the spark was a frickin' SAM.

Man oh man. What a long way to go for a cover-up."

Aviate 1138 says.....

In the Americans against Terrorism Paranoia way of life, surely had there been one shred of evidence that the mythical missile had ruptured Anything on Flight 800 then we would have heard by now. After all it could have been used as more 9/11 propaganda to invade Iraq couldn't it?

Zerozero name, zero intelligence. 100% paranoia.

Aviate 1138

Isn't politics amazing.

Here we have an aircraft exploding in flight, and the investigators put it down to a fuel system weakness, but the aircraft type is allowed to continue to fly.

We have another, smaller aircraft from the same manufacturer which has had a number of crashes which are so far unexplained but the finger of suspicion is pointing at the rudder trim or yaw damper system (can't remember which), but that model is also allowed to continue to fly.

Then we have that large three engined aircraft suffering a catastrophic fire off Canada, crashing into the sea, identified as a fault with the IFE, but what about the aircraft design which allowed the fire to spread so quickly with such disastrous consequences, but what the heck, let's allow the aircraft to keep flying anyway.

But Concorde, which crashed as a rusult of an EXTERNAL factor, ie, runway debris, is grounded for over a year, and eventually killed off.

As I said, isn't politics a curious thing?

I would have thought the reason for retiring the Concorde was more to do with economics rather than politics?

Just a guess though...

I doubt it Weasil.

Unlike B.A, Air France were losing their shirt on Concorde operations, so with a merger with KLM on the table, and Concorde operations costing them a fortune, whats an Air France board to do?

Scrub the Concorde, a decision that EADS (formerly known as Airbus) were more than happy with.

That will make the books look a bit better for the KLM merger negotiations.

With Air France grounding Concorde, and the manufacturer withdrawing support, BA had no choice but to follow suit.

I'm sure it was politics, but anyway, I was talking about the various decisions taken about whether to ground a particular aircraft type or not. It's more than a little curious how these decisions have gone over the years.

The grounding of the Concorde following the Paris crash was the straw which broke the camels back, after 9/11.

Zero intelligence. 100% paranoia
 

Aviate 1138--

Hey man, I won't sink to personal name-calling ok?

But if you were familiar with my other postings (I can forgive such an omission) you would realize that I'm quite critical of Bush Jr and his disasterous foreign policy. In short, I'm not searching for "more 9/11 propaganda to invade Iraq" because I'm of the opinion it's an unjust war to begin with.

Furthermore, TWA800 crashed *five* years before Sept. 11, 2001.

But more to the point, I never claimed terrorism--you did.

No group has ever claimed responsibility for that act. That fact along with the allegation of a cover up can only suggest one thing. I'll let you come to your own conclusions.

As for the "one shred" of evidence that's missing to point towards missle fire, well my friend, there's a ton of information out there and some of it is right here on pprune.

A simple search on TWA800 will reveal more than you asked for including testimony from some high ranking Army officers that actually witnessed the explosion, breakup and fall to earth.

In sum, thanks for allowing me the opportunity to expound on some important points and to explain that I was suspicious even in 1996 when I heard that the FBI was investigating along side the NTSB from the start.

Yes, that was several years before the average fat, dumb, ugly American became fat, dumb, ugly and paranoid.

Here we go again - conspiracy theories rise like the Pheonix from the ashes (no pun intended - a lot of people died).

The engineers have identified a fix or a least a system to minimise the risk. Everybody concerned with aviation should be looking to promote safety once the risk is identified and quantified.

Saying that, this is going to cost the industry MILLIONS.

Why should it cost the industry millions? The customers aren't interested in safety, they just want to pay a hundred and fifty bucks to fly from New York to Sydney with a 48 inch seat pitch, VOD entertainment and free booze all the way. Something's got to give and if the travelling public are to be protected from every minute risk at tremendous cost, then its the travelling public that ought to pay. And so they did until something called "De-Regulation" reared its head.

De-Regulation was a political gimmick, supposedly meant to remove the restrictive practices that kept fare prices high and open up free competition to the benefit of the public. Many of those allegedly restrictive practices were the industry's way of paying for meeting tightly controlled airworthiness standards. But if we are to be regulated tightly enough to eliminate every possible cause of an accident then we need those so-called artificially inflated fare prices to pay for meeting the regulations. Joe Public will never pay for his own safety unless he is obliged to and as long as he wants cheap travel he should be prepared to accept the increased risk.

I don´t want to enter the debate whether inerting is reasonable or not...
But when it comes to the A380, this aircraft should be "safe" of this system: The Air Generation Units will be located -forward- of the -wing- tanks; and on the passenger aircraft, there won´t even be a centre tank, let alone a heated one.
FedEx (and EK?) has ordered freighters, yes. But then again: No "heated" centre wing tank...

I guess they´ll have to find another way to slow down the A380...

J.V.

Part of the TWA investigation took part in a lab, where they tried to ignite a similar tank under ideal conditions. After weeks of attempting to get an explosion, they quit.

Wunnaful, just wunnaful.

Im not going to promote the whole missle/bomb or any other unexplained incident that brought down TWA 800, but there is one thing that has me wondering. When looking at the wreckage, especialy the rear part of the aircraft, that was supposed to have dived into the sea at over 450mph, it all looks rather undamaged. Looking at photos of another aircraft that dived into the sea in the same way (DC-9 that crashed into the Mediterrainean, i'll try get the photo) the fuselage is crumpled, much the same way as a flattened peice of carboard. The TWA fuselage doesn't seem to have this damage, yet from the reconstruction videos the aircraft dives straight into the ocean. There are large portions of the aircraft skin that retains it's shape. So did the aircraft dive into the ocean at sped or not? I just can't believe the there isn't more crumpling of the fuselage. Any thoughts, or explainations?

I don't recall the details of all the radar returns, but the aircraft did break up above the sea while in the so called dive and many of the pieces simply fell to the sea thereafter.

Just a thought re TWA 800! Under Annex 13, a law enforcement agency may parallel any investigation UNTIL it has been established whether or not a crime has been committed. IF the crash was indeed caused by an explosion in the centre tank, why does the FBI (who should have withdrawn) STILL refuse to release radar data and satellite photos?

Radar data germain to the accident is released by the NTSB. Other data including satelite images is either not germain to the accident based on other evidence or is classified since it would reveal capabilities that were not designed for aircraft accident reconstruction.

All such data that was pertinent was made available to the investigators. Data generated outside the official report as well as priveledged data is considered private by agencies/organizations other than the NTSB

zerozero ..if you suspect it to have been a missle, then it must have been something bigger than a shoulder launched SAM. And if that's the case, then a lot of people (sailors) are keeping quiet about it.

this thread is mighty misleading.
 

The first post in this thread is from a NY Times article by Matthew Wald dated 17 Feb 2004.

http://www.freerepublic.com/focus/f-news/1080052/posts

The FAA has since announced that this initiative (and many others) is to be shelved until the following decade (at which time it will be announced that it's irrelevant as the affected airplane types are no longer operating and because there's no-one left in the agency who can recall why they were going to do it in the first place)..

So this thread is mighty misleading.