Posted on 02/17/2004 2:40:05 PM PST by ZGuy
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.
Like I said earlier, a bomb, maybe. A missile, NO. Take away all the "eyewitnesses" and the missile theory goes poof! I have yet to read an eyewitness account of any airliner crash where they get more than a small amount of the facts straight. Also, these people were not anywhere near the actual crash. They were miles away seeing an event that at the time they had no idea what it was. Even when eyewitnesses are within spitting distance of a crash, (AA 587) they cannot agree on what actually happened.
The so called "facts" of the missile theory are great, as long as the facts that rule out a missile are ignored. The problem with conspiracy theories, is one can be created to fit any event. If it was a U.S. Navy ship, it would be impossible to keep the entire crew quiet for all these years. Someone would leak it to the press that their ship fired a SAM at the same time TWA800 went down. Also, there were not any SAM equipped ships within range of TWA800 unless we have a secret, ship launched version of the Phoenix missile.
The guidance radar for the SA-6 is separate from the launcher. Both are mounted on armored, tracked vehicles. Both the radar and the launcher are heavy and complex. You can't just unscrew them from the top of an armored car and bolt them to the deck of a boat.
"Yeah, an SA-6 is big and heavy. But so was the boat and explosives that almost sank the Cole."
The Cole was hit by a Zodiac boat. Even if you could bolt an SA-6 launcher to a Zodiac, you'd sink the whole thing with the missile launched. Furthermore, the SA-6 system cannot fire on the move. It must be stationary. You could set up the whole system on the deck of an aircraft carrier and it wouldn't work. That is why we don't just strap patriot missile systems to cargo ships and call them guided missile cruisers.
I'm afraid you are a little confused. The SA-6 missile relies on semi-active terminal guidance to guide it to impact. That means that a ground based radar must illuminate the target with radar energy that the missile then homes in on. The missile itself does not have an active radar. Very few missiles do. In fact, I think the only ground launched anti-air missile that does is the ground launched variant of the AMRAAM missile.
"The Cole was hit by a fiberglass hull boat that contained hundreds of pounds of high explosive."
Almost every eyewitness and official account describes the boat as a Zodiac. Some Zodiacs have a fiberglass hull, but regardless, they are small and couldn't carry a truck, nevermind a missile system.
Yes, but a surface to air missile doesn't guide on any radar energy. The target tracking radar that guides a missile like an SA-6 provides an incredibly powerful and very narrow beam of radar energy with specific frequency, pulse width and modulation. The missile only "sees" that radar illumination.
I agree that it is incredibly unlikely that anything was launched from land the night TWA800 went down. No SAM system is portable enough and descrete enough for that to happen without thousands of people on Long Island being aware of it.
No. It doesn't.
"There is no technology that would radar illuminate a plane in a narrow beam like a searchlight over that great a distance."
Yes, there is. The Navy's Aegis system, the Army's Patriot system, and the Russian SA-10 are all easily capable of doing that.
If you read this please note the paragraph stating:
"The SA-11 GADFLY system also can be fitted with a supplementary electro-optical sighting system for use in a severe jamming environment, which would overwhelm the normal semi-active radar homing system -- in which case the missile uses radio-command guidance."
There are many other SAMs with similar capabilities, and all could fit on craft smaller than a WWII PT boat, which is what I would think would be an ideal platform for this type of attack.
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