| This thread has been locked, it will not receive new replies. |
Posted on 06/01/2002 11:46:30 AM PDT by Asmodeus
This sounds very much like Clancy's book 'Executive Orders'
Damn, that guy is prophetic !
Right or wrong, none of these factors apply to CI611.
It makes contradictory nonsense. Do you believe Flight 800 was the victim of a bomb? Bill Donaldson alleged that it was the victim of a "missile(s) shootdown".
But spontaneous combustion of a fuel tank on an airplane that's been flown more than almost anyother in the history of aviation?
Nobody will know whether any of those is applicable to the China Airlines crash until a great many more facts are known.
But Flight 800 was not the victim of any of those. See the following.
FBI Chief Metallurgist Blows The Whistle On Kallstrom's Wild Goose Chase
Flight 800 was struck by a shoulder-launched SAM, probably a Stinger, probably a Stinger we gave to the Afgans to repell the Soviets. The 'evidence' given by the FBI and NTSB is not as compelling to me as the eye-witness accounts from so many people.
Tuor
And since when does jet fuel, which is like kerosene, explode from an ignition source? Works in a diesel engine when it is under high compression and thus extremely high temperature.
Gas vapor could possibly spark due to static discharge. However, I do not believe such a thing happened in this case. If the 747 was prone to this sort of problem, I have a suspicion that it would've shown up sometime prior to this in its 30 years of use.
One of the witnesses was on the radio last night, and she said she definitely saw a light source heading up towards the plane and strike it. The FBI *did* try to supress the evidence collected from hundreds of eye-witnesses. I've also heard that the Brits want the investigation re-opened (I think it was the Brits).
Tuor
Good point. The party line has been talking about jet fuel as it's high octane aviation gasoline. Maybe some folks out there remember being on a piston-engined airliner when it first started up and there was a heavy smell of gasoline in the cabin. The "no smoking" signs were lit for a reason!
But jet fuel is kerosene based. And jet-A is also carried as a semi-gel which is designed to counteract the vapor problem.
Here's a good article on kerosene fuels:
From http://www.geocities.com/vialls2/ignition1.html:
Concorde Ignition
Copyright Joe Vialls - 15 August 2000 - All Rights Reserved
... Later on in the report, the Primus stove is used as a prime example of how difficult it is to ignite kerosene based fuels like the Jet A1 in Concorde's wing tanks. Even if Jet A1 is momentarily ignited, sustained combustion of this fuel is far more difficult.
Nearly a month after the crash of AF 4590, investigators are still uncertain what led to the catastrophe in France. Wild media speculation has largely abated, though rumours still hang in the air about a piece of metal on the runway "cutting" one of Concorde's tyres, which then allegedly exploded, hurling a large chunk of rubber up through the wing section and causing the devastating fire. This simplistic story fails to take two known facts into account. So far Goodyear has refused to confirm the small fragments of rubber later found on the runway came from a Concorde tyre, and all eight wheels and tyres were located at the crash site. Though all eight were badly damaged in the crash itself, no pieces of wheel or large chunks of tyre were missing. In other words, media speculation is not supported by known existing scientific evidence.
Aviation crash investigators work under enormous pressure, with governments and airline operators demanding instant answers to extremely complex problems. Sometimes the pressure is so intense that investigators take the "soft option", i.e. go along with government or airline wishful interpretations of events, without first taking all possible causes for the crash into account, and excluding those known to be scientifically impossible. This is of critical importance, because as Arthur Conan Doyle once wrote so accurately: "When you have ruled out the impossible, then whatever remains, no matter how improbable, is the truth." Though none of us yet knows the exact cause of the crash, we do have some of the earlier details, certainly enough to discriminate between known facts and wild media speculation.
Everything was fine on 25 July when Concorde's brakes were released and afterburners lit on the runway at Paris Charles de Gaulle. We know all engines and afterburners remained OK for at least eighty-percent of the take off roll, or Concorde could not have achieved V1 (its go/no-go speed). Remember here that Concorde is not the "rocket" many people believe the aircraft to be. With a full fuel and passenger load en-route for New York, AF 4590 needed every single pound of available thrust from all four engines and afterburners to accelerate to V1. If for any reason the aircraft was sluggish before reaching V1, or had used too much runway when approaching this crucial decision point, take off would have been instantly aborted by the Captain.
Fine so far, from the bald facts above we know that Concorde was past V1 when #2 engine first failed. This fact is corroborated by two radio messages sent back-to-back by the Captain: "failure in number two engine" and "too much thrust". Cryptic though his comments may sound, they tell the whole story at that point. "Failure in number two engine" was extremely serious at that stage and the Captain dutifully reported the fact to the tower. "Too much thrust" or "too much speed" literally meant that aircraft velocity was already higher than V1 when #2 engine failed, making it impossible to safely abort the take off. As previously stated, had #2 engine failed before reaching V1, take off would have been instantly aborted, as per Pilot's Notes. So we have now established scientifically from operating procedures, and from known aircraft performance and the Captain's own words, that the problem started at some point between V1 and VR - the latter being the speed at which the aircraft rotated off the runway.
At this stage it is also critical to note that the Captain did not report an engine fire, which he certainly would have done if an engine fire existed and he knew about it. Nor did the fire sensors in #1 and #2 engine bays report an engine fire at any time. Fire warning Klaxons or bells on the flight deck have considerably more volume than a human voice, meaning they would be heard clearly in the background on the cockpit voice recorder, as they have been on several occasions in the past. Not on Air France Flight 4590. The Concorde CVR contains no sound of fire warning klaxons or bells at all. So we either believe that all of the fire sensors in engine bays #1 and #2 suffered a spontaneous failure, or we take the scientific view that the sensors failed to activate simply because there was no fire inside engine bays #1 and #2. In the absence of any hard evidence to the contrary, investigators are obliged to take the scientific view. Media claims that the tower reported a fire to the Captain "on the runway" are rubbish, or an unfortunate misinterpretation of events. The official sequence shows that the tower advised the Captain about the fire "fifty-six seconds after take off commenced", by which time Concorde was airborne and vanishing rapidly in the distance.
For all practical scientific purposes it is also possible to rule out a tyre failure before V1, again based on known operating procedures, aircraft performance, and an earlier incident with an Air France Concorde at Washington in mid 1979. When a tyre fails during the take off roll, the first manifestation is drag, which in the case of AF 4590 using only four high pressure tyres per main bogie, would have been massive. The failed tyre or tyres would have dragged the aircraft to the left, and more importantly reduced acceleration to the point where take off was aborted. In the Washington incident tyre failure occurred beyond V1, but was certainly noticed by both passengers and crew. The Captain immediately notified the tower, while a passenger later told the media on camera: "The vibration was incredible, it felt like we were driving over speed bumps at fifty miles an hour!" The Captain of AF 4560 at Paris Charles de Gaulle reported no such vibration at any time, though in isolation this does not prove a tyre or tyres did not fail beyond V1. Perhaps the Captain was simply preoccupied with #2 and then #1 engine failures. Perhaps he was, but "perhaps" is not a scientific term likely to impress any member of the investigation team.
For the discerning investigator, the Washington incident serves to clarify this latter point. When the Air France Concorde burst two tyres after V1 at Dulles In 1979, all four engines and afterburners maintained 100% thrust, allowing the Captain to just get the aircraft off the ground, dump fuel and then return for a landing. But according to the reports it was a very close call. Though not operating at Maximum All Up Weight (MAUW), the Washington Concorde slewed violently to the left, and was almost out of runway when it finally became airborne. Now superimpose these known data on AF 4590 at Paris Charles de Gaulle, which was operating right on Maximum All Up Weight and lost one and a half engines and afterburners between V1 and VR. The harsh scientific reality is that the massive drag of a burst tyre or tyres at that point, added to a known 25 to 37.5 percent reduction in engine thrust, would have prevented the aircraft from achieving VR and getting airborne. Instead, Concorde would have remained on the ground, eventually ramming the scenery at the end of the runway. End of story.
So to summarise at this mid point in the report, investigators know from existing data that Concorde AF 4590 lost #2 and then #1 engines between V1 and VR, but these engine failures were not caused by a known or reported fire in either engine bay. Because the aircraft managed to get airborne at MAUW with a 25 to 37.5 percent reduction in overall engine thrust, investigators also know that Concorde did not burst a tyre or tyres before V1, or between V1 and VR. As stated in reports posted on this web site immediately after the crash, the media managed to get everything back to front. The only realistic scientific possibility for the engine failures, is that the raging fire in Concorde's inboard port wing cut the fuel supply to #2 and then #1, causing both to fail because of simple fuel starvation. The two main questions facing investigators are therefore (1) how did the fire start, and (2) how did it manage to stay alight?
There are many who claim that the fuel was simply lit by the intense heat of the afterburners on #1 and #2 engines, but this fails to take into account the scientific reality that the fire in the inner port wing section is well forward of the turbine and afterburner engine stages, as shown clearly on the Japanese amateur photo. Fire cannot and does not run upwind, in this case head-on into the 200+ mph slipstream blowing from forward to aft over Concorde's wing section. Proof of this fact abounds on thousands of feet of video taken at various car race tracks. Out of interest I played a video of an Australian "V8 Supercar" race in which two of the cars collided, then spun apart again, finally coming to rest 110 yards from each other with a substantial raw fuel trail between them. The first car burst into flames, in turn igniting the highly volatile gasoline trail leading to the second car. According to my stopwatch, the flame front advanced from car one to car two at 57 mph, proving that any such scenario with Concorde was impossible. There are other examples of course, and older readers will recall how during World War Two, pilots frequently dived to increase airspeed and "blow the fire out".
Because flight and ground engineers are not experts in the complexities of fuel ignition and sustained combustion, I approached the research labs of two major Australian oil refineries for assistance. Most puzzling of all was that the Jet A1 Concorde was carrying in its wing tanks is probably the most stable fuel known to man. Basically kerosene with minor non-flammable additive packages, Jet A1 has a flash point of 38 - 40 deg C, but this has very little to do with a raging fire inside a closed wing section devoid of oxygen. Flash point is measured artificially under pressure in a chamber, and officially defined as: "The temperature at which the vapour above a volatile liquid forms a combustible mixture with air. At the flash point the application of a naked flame gives a momentary flash rather than sustained combustion, for which the temperature is too low."
So inside the wing, provided there was room in the compartment for a vapour cloud to form, and provided oxygen was present, ambient temperature might have been high enough to momentarily "flash" the vapour, but that temperature was far too low for the sustained combustion visible on the amateur photo, and on the later video of Concorde in flight. With this in mind I asked the lab scientists for their expert opinions on the minimum temperature required for sustained combustion. All were unanimously of the view that the 100% boil off temperature of Jet A1 (250 deg C) would be essential, and even then only if oxygen was present in sufficient quantity. For purists reading this report, the initial boiling point of Jet A1 is 150 deg C, 10% boil off is 170 deg C, 50% boil off is 200 deg C, and 100% boil off is 250 deg C. One scientist was clearly worried about the process of combustion, and kept asking me "But where did the oxygen come from?" Unfortunately I was unable to provide an answer.
In an attempt to simplify his explanation of the difficulties involved in lighting and sustaining combustion with kerosene, a lab technician at the second refinery reminded me of the old-fashioned Primus stove, which is why there is a picture of one at the top of this report. It is an excellent analogy, because the original fuel specification for the Primus stove was almost identical to Jet A1. So much so, that an enterprising camping equipment store owner in Vancouver nowadays buys Jet A1 in bulk, then repackages it and sells the resulting "camping stove fuel" at substantial profit.
To ignite the main kerosine fuel supply in a Primus stove, it is first necessary to fill the circular tray beneath the burner with methylated spirits, which is then ignited in order to pre-heat the fuel supply pipe running up through the middle from the kerosene tank at the bottom, to the outlet jet at the burner on top. Critically, the meths must heat the centre fuel supply pipe to a temperature which ensures the kerosine flowing through it is heated above its 100% boil off temperature of 250 deg C. When this is done, you simpy light the kerosine vapour at the jet, and oxygen is drawn in from atmosphere to provide sustained combustion at the burner. If you try to light the kerosene burner without first burning enough meths in the tray, the result will be failure. Hopefully most readers will recognise the importance of this analogy, and its direct relevance to the fire in Concorde's wing. In order to determine the root cause of the Concorde crash after take off from Paris Charles de Gaulle, investigators must work out which bays and components were involved, and identify the sources of fuel, flame ignition, oxygen, and 250 deg C temperatures. Not an easy task.
Joe Vialls, former member Society of Licenced Aeronautical Engineers & Technologists .
------------------------------------------------------------------------
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.