Tech Log The very best in practical technical discussion on the web

Twa 800

Old 27th Sep 2007, 03:13
  #1 (permalink)  
Thread Starter
 
Join Date: Apr 2005
Location: Australia
Posts: 33
Likes: 0
Received 0 Likes on 0 Posts
Twa 800

ARAP E-Mail on Tank Explosions

To whom it may concern,

At 1:00pmET today, the Discovery Channel presented its TWA800 "documentary". As a manufacturer of UL Listed steel fuel tanks, I was disturbed by the presentation of a "scientific test" which demonstrated that a Boeing 737 fuel tank under "similar conditions" would indeed explode if a spark were introduced to the tank. I am therefore compelled to write in the hope that someone with a vested interest might read this.

I sense serious defects with the test as presented. As a manufacturer of steel fuel tanks for both fuel oil and gasoline use, there are several basic axioms which guide our designs.* One basic tenet is that a properly designed and vented fuel tank will not explode, even when engulfed in fire. The issue with a fuel tank is not explosion-- it is rupture from overpressure from gases produced by boiling liquid. Provided that the tank is vented, it will not rupture. We don't worry about explosion as much as tank rupture from overpressure or tank structural failure from heat. Most important, however, is that a fuel tank fully engulfed will not explode because there is no oxygen in the tank.

All of the "air" has been displaced by heavier-than-air fuel vapors. Remember that these tanks are vented-- these are not pressure vessels. So the residual fuel that would always be present in the tank would give-off vapors which displace the air out the vent. The Boeing 747 fuel tank in question had not been emptied. Presumably it had been quiescent on the ground for many hours prior to flight. The fuel tank should therefore have been fully saturated in fuel such that all "air" had been displaced. Furthermore, as the aircraft climbed, and pressure dropped, the tank would have further evacuated-- fresh air would not have been drawn into the vented tank until the aircraft descended. As air pressure dropped, so would the boiling point, resulting in a greater concentration of vapors and displacement of oxygen. Therefore, a spark or even an open flame could not have ignited the vapors.

Perhaps this explains why aircraft fuel tanks are not exploding all the time-- and car fuel tanks as well. In fact, TWA800 is the only aviation case I have knowledge of and I am an interested person who follows these things (I am a private pilot with a life-long aviation passion).

The Discovery Channel presentation is defective:
1. The test tank was freshly filled and immediately tested, not allowing time for the atmosphere within the tank to saturate with vapors as would have been the case with the TWA800 aircraft.
2. The test tank had air circulation fans installed within, which would have both inhibited evacuation of air and introduced fuel droplets into the air. The 747 had no such mixing fans.
3. The test tank was tested at atmospheric pressure. The TWA800 event occurred at 15,000 feet or so, where pressure is greatly reduced.
4. The test tank was artificially heated by a salamander perhaps producing spot overheating. The TWA tank would have been both at uniform temperature and would have cooled substantially during the climb.
Furthermore, the flash point of Jet-A is well above 100F. The test was performed at approx 125F, presumably below the flash point of Jet-A. A flammable liquid can only ignite in free air when the flash point is exceeded.

Artificially introduced droplets were probably introduced in the test. In fact, the test appears to be so defective as to be contrived such that the test tank was indeed a "bomb" producing desired results.

I am disturbed that this is presented to the gullible public as fact and the final word. I believe that the facts of metallic tank construction weigh strongly against the "results of the scientific test" presented on Discovery. Those of us who manufacture steel fuel tanks know this.

I have no political ax to grind and am not a conspiracy nut. However, as an engineer, a pilot, a person of knowledge and a manufacturer of fuel tanks, I have severe doubts that the TWA800 tank exploded from an internally introduced spark. The reasons presented above substantiate those doubts.

I hope that this letter will help advance your search for the truth.

President
Simplex, Inc.
nick charles is offline  
Old 27th Sep 2007, 03:34
  #2 (permalink)  
 
Join Date: Aug 2005
Location: fl
Posts: 2,525
Likes: 0
Received 0 Likes on 0 Posts
TWA 800, in my opinion, was investigated from what they wanted the cause to be backwards to what could have caused it to happen that way. They decided the center tank exploded causing the disaster. Anything saying it wasn't a fault in the center fuel tank wasn't pursued seriously. Just my opinion.
bubbers44 is offline  
Old 27th Sep 2007, 05:45
  #3 (permalink)  
 
Join Date: Jan 2007
Location: USA
Age: 50
Posts: 52
Likes: 0
Received 0 Likes on 0 Posts
Twa 800

Everyone knows it was a missle.
expatpilot4life is offline  
Old 27th Sep 2007, 06:11
  #4 (permalink)  
PBL
 
Join Date: Sep 2000
Location: Bielefeld, Germany
Posts: 955
Likes: 0
Received 0 Likes on 0 Posts
nick charles,

there is extensive investigation, including reports from the American Chemical Society, in the TWA800 docket on the NTSB WWW site.

I also wrote a paper on the energy required for ignition, which you can find on my WWW site (EMI, TWA 800 and Swissair 111).

This is not the only documented incident of CWTs exploding on Boeing airframes. (I am using the word "explosion" here to mean a rapid burn, with significant overpressure, after ignition.) Those who favor some other theory have to explain how their theory accounts for those other instances also. (In the case of our missile-theory advocates, it most obviously does not account for those other instances.)

The NTSB, and the American Chemical Society, believe that it is possible to ignite vapors in a CWT with a result similar to that in TWA 800. This contradicts your suggestion (as I understand it) that you don't see how it is possible, so perhaps you should check out the docket materials to see where either they fail or you fail.

PBL
PBL is offline  
Old 27th Sep 2007, 11:39
  #5 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
With a center fuel tank you don'y really have to blow out the four sides to cause a serious problem with the aircraft. TWA800 proved this. The center tank is an integral structural body of the arcraft and like a wing if you take out a spar or two you are going to have a serious cascading problem.
lomapaseo is offline  
Old 27th Sep 2007, 19:49
  #6 (permalink)  
 
Join Date: Jul 1998
Location: Cornwall
Posts: 86
Likes: 0
Received 0 Likes on 0 Posts
"Perhaps this explains why aircraft fuel tanks are not exploding all the time-- and car fuel tanks as well."
No, not all the time, but I know of at least 2 C130's whose wings have blown up due to defective booster pumps arcing across a defective phase when being switched off/on.
And as for conspiracy theories, well, we all try to keep an open mind, but for those of us flying 747's in recent years, the raft of bulletins, changes to AFM's, drills, QRH's, all to ensure the integrity of the Centre Wing Fuel Tank by making sure the respective fuel pumps are covered in all conditions, all to make sure we don't get downed by a missile???!!!
Sorry, sarcasm and all that, but my meaning's clear.
Captain Sensible is offline  
Old 27th Sep 2007, 21:25
  #7 (permalink)  
 
Join Date: Apr 1999
Posts: 326
Likes: 0
Received 0 Likes on 0 Posts
Oh well, at least I tried!
Casper is offline  
Old 27th Sep 2007, 22:02
  #8 (permalink)  
 
Join Date: Feb 2005
Location: flyover country USA
Age: 82
Posts: 4,579
Likes: 0
Received 0 Likes on 0 Posts
But then -
What explains the PR 737 ground explosion in 1990 that preceded TW800? Wasn't it unequivocably the center tank?

And don't forget - early B-47's used to inexplicably blow up in the landing pattern after long training missions. The problem went away after changing out the DC fuel pumps (w/commutators) for AC pumps. (This from an ex-SAC pilot who lost a colleague or two in the 50s)

Last edited by barit1; 28th Sep 2007 at 01:02.
barit1 is offline  
Old 28th Sep 2007, 04:38
  #9 (permalink)  
 
Join Date: Dec 2006
Location: The No Transgression Zone
Posts: 2,483
Received 6 Likes on 4 Posts
Well, my 'conspiracy theory agrees 100% with the NTSB...

However, as an aside my uncle a retired Naval officer, informed me that during the time of flight 800 the Navy was testing a very high powered radar antenna {not entirely sure exactly what} installation.

He then informed me that they frequently 'lock on to civil airliners' for practice drills and calibration of such equipment [and just look around that area on sectionals and you know they do 'something secret' around that airspace] perhaps that was the initial trigger of the arcing condition perhaps an overvoltage/surge was the final dagger in the heart of flt 800

so while I agree that the ingredients for disater existed I do not rule out that there was maybe so "extra help" getting it started

Now, my uncle is very sane and knowledgeable about Naval operations [having served on many many ships in his 20 years of service] ...and he didn't say that that was definitely the cause but........
Pugilistic Animus is offline  
Old 28th Sep 2007, 17:23
  #10 (permalink)  

Aviator Extraordinaire
 
Join Date: May 2000
Location: Oklahoma City, Oklahoma USA
Age: 77
Posts: 2,394
Likes: 0
Received 0 Likes on 0 Posts
For now I am still going along with the official NTSB findings. However, I would consider a different solution, if it based on actual facts, not Internet unprovable theories.
con-pilot is offline  
Old 28th Sep 2007, 17:30
  #11 (permalink)  
PBL
 
Join Date: Sep 2000
Location: Bielefeld, Germany
Posts: 955
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Pugilistic Animus
However, as an aside my uncle a retired Naval officer, informed me that during the time of flight 800 the Navy was testing a very high powered radar antenna {not entirely sure exactly what} installation.

He then informed me that they frequently 'lock on to civil airliners' for practice drills and calibration of such equipment [and just look around that area on sectionals and you know they do 'something secret' around that airspace] perhaps that was the initial trigger of the arcing condition perhaps an overvoltage/surge was the final dagger in the heart of flt 800
No. This is the hypothesis that Elaine Scarry proposed in the NYRB. It has been definitively discredited by NASA and myself and Willie Schepper. Please read the NASA report in the docket, and read our paper.

PBL
PBL is offline  
Old 28th Sep 2007, 19:56
  #12 (permalink)  
 
Join Date: Jun 2005
Location: AEP
Age: 80
Posts: 1,420
Likes: 0
Received 0 Likes on 0 Posts
747 CWT Scavenge Pump

Attn. Nick /
xxx
Ex PanAm 747 pilot, then based JFK, I had many friends flying 747s with TWA. We often compared our procedures and discussed our airplanes and their differences, as I was often instructing in classrooms or simulators at the PA Academy in Miami... I now fly 747s in Argentina, manager pilot training, and when TW 800 crashed, no need to tell you, we were in contact about the facts and... theories.
xxx
No need to say, all ex-PanAm flight crews, like myself, immediately thought about "foul play", a bomb, a missile... after all, PanAm, as well as TWA, were considered by terrorists as the perfect targets representing the USA when overseas. It took me a long time, until the final report by the NTSB, to believe that TW 800 went down with a CWT explosion... Remember Lockerbie.
xxx
That the explosion occured at some 13,500 feet in the climb, is no surprise. TW 800 was dispatched from JFK to CDG, with wing tanks and reserves near full, but no extra fuel was required nor loaded in the CWT. The plane had landed in JFK arriving from Europe, with the usual residual fuel remaining in the CWT. And yes, that fuel was warm, because of the A/C packs used on the ground at JFK. How warm...?
xxx
An AFM 747 limitation is "maximum fuel temperature" for Jet A or Jet A-1 to be 54.5ēC in the tanks. The fuel is generally warmer in the CWT because of the A/C packs. You said that fuel cools off rather fast... well, it cools off (not so fast, but it does cool) in the wing tanks, not much in the CWT...
xxx
There is no "CWT fuel temperature" that we can read in the 747. We can read fuel tank temperature for tank nē1, or for each separate engine feed. here in Argentina, if the fuel gets very cold on our very long flights (minimum temperature for Jet A or A-1 limit is 37ēC in our limitations), we sometimes keep 2 or 3,000 kilos of fuel in the CWT until needed to be used to warmup the engine feed lines, if needed. I know that after 10 hrs in cruise, that fuel remains rather warm in the CWT, maybe 10 or 20ēC warmer than wing tanks.
xxx
However uneducated we pilots and flight engineers are in the 747, it is very likely that the CWT exploded when the F/E on the flight operated the "scavenge pump". Why...? With PanAm, as well as with TWA, our F/E's SOP performed after passing 10,000 feet in the climb, was to activate the scavenge pump to "suck the last drops" of an "empty" CWT and transfer that fuel into the nē2 main tank. Many of us believe that this, triggered the explosion, probably with a short in that electrical wiring or motor. So, 13,500 feet makes sense...
xxx
I know that UAL F/Es used to do same SOP, but at 18,000 feet in climb... and here in Argentina, we did that scavenge, to complete our "after takeoff checklist" at flap retraction at some 3 to 5,000 feet if our CWT was empty. No need to tell you that we no longer do such a procedure... If a few liters of fuel remain in the CWT, well, who cares...? -
xxx
A few years ago, smartass as I am, with my Zippo lighter, and filled it with a few drops of Jet A-1. I could never use it again, and had to buy a new one. Jet fuel is extremely difficult to light-up. At PanAm, we flew many military MAC flights contracts, and the Air Force often delivered Jet B fuel (JP-4). For that fuel, we had a lot of limitations, such as maximum pressure for fueling, and maximum temperature reduced to 43ēC...
xxx
Thank you for your input about steel tanks, it is appreciated. However good the "Discovery Channel" is, obviously it is for the general public.

Happy contrails
BelArgUSA is offline  
Old 28th Sep 2007, 20:51
  #13 (permalink)  
 
Join Date: Sep 2007
Location: texas
Age: 75
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Twa 800

It should be clear to the most myopic that there is something fishy in the whole "tank" issue. With eye witnesses seeing two trails heading towards the craft(Coast Guard officer in a helicopter) to investigations of rocket propellant on seats. Not to mention the idea that a jet can continue to rise after a catastophic explosion. NTSB is the same guys that told us that UA 93 nosed over into the ground in Pa. when parts and pieces were found miles away. The fuel tank is easier to sell and eliminates law suits against a friendly fire situation.
robertsgt40 is offline  
Old 28th Sep 2007, 23:28
  #14 (permalink)  

Aviator Extraordinaire
 
Join Date: May 2000
Location: Oklahoma City, Oklahoma USA
Age: 77
Posts: 2,394
Likes: 0
Received 0 Likes on 0 Posts
He's from Texas, ignore him.
con-pilot is offline  
Old 29th Sep 2007, 03:49
  #15 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
Ignore him yes, but I do expect the mods to clean up the extraneously bolded font
lomapaseo is offline  
Old 29th Sep 2007, 04:24
  #16 (permalink)  
PPRuNe supporter
 
Join Date: Dec 2003
Location: Planet Earth
Posts: 1,677
Likes: 0
Received 0 Likes on 0 Posts
Not a conspiracy person myself, but after reading about the investigation it seems very fishy, thanks BelArg for your experienced perspective.
Dream Land is offline  
Old 30th Sep 2007, 10:52
  #17 (permalink)  
 
Join Date: Apr 1999
Posts: 326
Likes: 0
Received 0 Likes on 0 Posts
Good thread. But can anyone explain why the FBI still (after 10 years) lists this investigation as "pending inactive," the one and only category that permits them to withold evidence? If it was, in fact, a CWT explosion and NO crime, why is the FBI STILL even involved?

Also, why does the FBI STILL withold the pathological evidence about foreign objects removed from the bodies of the victims? Even the official pathologist has not been informed!
Casper is offline  
Old 30th Sep 2007, 14:47
  #18 (permalink)  
IGh
 
Join Date: May 2007
Location: Castlegar
Posts: 257
Likes: 0
Received 0 Likes on 0 Posts
Examination of the victims' bodies

Just above, Casper posed a question and a comment:

"... why does the FBI STILL withold the pathological evidence about foreign objects removed from the bodies of the victims? Even the official pathologist has not been informed!"

Nobody doubted Dr. Shanahan's daily briefings regarding his examinations of the victims, nor any "objects removed from the bodies". He was honest and open regarding such medical evidence [AAR also cites the Medical Forensic Group Chairman’s Factual Report, dated October 17, 1997].

The AAR reviews this subject of medical exams on pg 85:

= = = \/ = = = EXCERPT from AAR 00-03 = = = \/ = = =

Exhaustive analysis of all available medical data on the victims of TWA Flight 800 by an experienced team of forensic pathologists, biomechanicists and criminal investigators failed to find any evidence that any victim was directly exposed to a bomb blast or missile warhead detonation. This finding makes it highly unlikely that a localized explosion occurred within the passenger cabin of TWA Flight 800.

-- All injuries found in the victims were consistent with severe in-flight break up and subsequent water impact.

-- Injury and burn patterns to the victims as well as some body locations suggest that there was a severe break up of the passenger cabin early in the crash sequence.

-- Fire propagated ...cabin zone located above the CWT ... after most occupants [of this section] had been ejected. The small number of passengers with burn injuries exhibited only superficial burns consistent with exposure to a flash flamefront.

= = = /\ = = = END EXCERPT from AAR pg 85 = = = /\ = = =
IGh is offline  
Old 30th Sep 2007, 22:04
  #19 (permalink)  
Thread Starter
 
Join Date: Apr 2005
Location: Australia
Posts: 33
Likes: 0
Received 0 Likes on 0 Posts
Just two questions.

If it was a CWT explosion and no crime was involved, why are law suits under the FOI Act still required to obtain information? - more than ten years after the event

And why does the FBI still list the case as "pending inactive?"
nick charles is offline  
Old 30th Sep 2007, 22:42
  #20 (permalink)  
 
Join Date: Jul 2002
Location: Trailer in BC
Posts: 313
Likes: 0
Received 0 Likes on 0 Posts
When I was new on the panel on the classic, I did everything possible ( not on purpose) to blow up the CWT and nothing!! I don't really believe the tank theory. The missle theory seems more likely as there were so many attempts to cover up info by the government and there were also several reputable eye witness's.
fesmokie is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.