sitemap Text of Second Letter to NTSB from Donaldson

Text of Second Letter to National Transportation Safety Board

"This fuel is so safe a maintenance employee could have taken a smoke break
standing in the residual fuel of TWA's tank, ... and put out his lit match in
the fuel without consequence at temperatures up to .... 126°F!"

CDR. William S. Donaldson
September 18, 1997

Mr. James E. Hall

Chairman, National Transportation Safety Board

490 L'Enfant Plaza East, SW

Washington, DC 20594

Mr. Hall:

I appreciate you response, however it is obvious either I've failed to communicate or that you and I have different understanding of the fundamental elements of science that apply to this incident.

Subsequent paragraphs will demarcate these elements and provide the proof that you requested.

First, I feel compelled to address the more emotional aspects of your reply.

In your response you dismiss my allegations by distancing yourself from the flawed tests you had touted in official safety recommendations.(NTSB Safety Recommendation A-96-174 through 177, 13 Dec 96) You also dismiss the media hyperbole your agency fully promoted and encouraged. You voice dismay at personal insult and allege I am doing the same to the Myriad Federal Participants. You wrap yourself in the flag (by citing a two year Army career started before the end of the draft). You repeat the Administration's Mantra," we have no evidence of a Criminal Act", (as if it was a bank fraud investigation). Then you impune a retired senior Naval Officer's motives and suggest I don't enjoy good mental health! How typical of this administration, it's absolutely Carvellian!

Understand the tone of my letter you express concern for was the result of hundreds of uncompensated man-hours of careful study balanced against the intimate knowledge of jet aircraft piloting, maintenance, and mishap investigation assimilated during a twenty-five year military career. Also be assured somehow during that span my "delusional state of mind" as you put it, must have been in remission, that is unless the 19 personal and 5 unit awards hanging in my den are figments of my imagination!

Mr. Hall my correspondence wasn't about personal malice and it certainly wasn't an effort to denigrate Federal employees. It was about leadership and duty, specifically your leadership and duty.

Believe me there nothing I am doing that will adversely impact the personnel within NTSB beyond your tenure. However even the slightest hint of political interference by you or your mentor with their work product subverts the whole Federal effort. Aviation professionals depend on proven science and engineering for their very lives. I believe you have led the NTSB onto the Horns of a dilemma. You may have fooled the media and enough congressional staff to get through this, but you don't pass muster with professionals. The funding of research grants and flight testing are but futile attempts to prove an impossible premise; the assumption that explosive atmospheres composed of air and hot Jet A-1 fuel vapors in B747 center wing tanks occur during normal aircraft operations. THEY DO NOT!

There are two ways explosive atmospheres can be created in B747 fuel tank ullages.

(1) Fuel vapor/air if a highly volatile fuel like JP4 or JetB is used and

(2) Fuel mist/air when a low volatile fuel like Jet A-1, JP5 or JP8 is in use but it has to be coupled with extreme agitation or shock to the tank.

There is no question a fuel air explosion occurred in FL800's CWT ullage, in fact it is the very power of the over pressure that points unflinchingly at mechanical misting of residual fuel as the internal primordial event.

Jet A-1 like all petroleum based fuels is a variable blend of may complex hydrocarbons the most accepted molecular weight is given at 168 and the chemical formula is stated as C12H24. (Air Force Tech Assist team, San Antonio, TX)  Accordingly a mole of Jet A-1 vapor is nominally six times as dense as the equivalent mole of air (molecular weight 28).

I will call your attention to the flammability range (Percentage By Volume) of Jet A-1 vapor contained at enclosure (1). (Pg. 71, Table 8, Handbook of Aviation Fuels Properties, CRC Report 530, 1988)  This table also depicts the minimum temperature (closed cup flash point) where a flame introduced into the cup of heated fuel will ignite the minuscule amount of vapor at the surface of the fuel. Because C12H24 produces a very heavy vapor molecule, at aircraft operation temperatures, if it exists at all, it stays very close to the surface of the liquid fuel and does not mix well with air. In other words the table tells us at 53°C or 127°F just enough molecules of C12H24 are energized to break the surface tension, leave the liquid and mix in a 6:994 ratio (.006 Vapor, .994 Air) with air in a thin layer just above the surface. It also means this fuel is so safe a maintenance employee could have taken a smoke break standing in the residual fuel of TWA's tank, reached down and put out his lit match in the fuel without consequence at temperatures up to and including 126°F!

You have stated, approximately 600lbs of residual Jet A-1 were contained in TWA FL800's CWT at the time of the mishap. You have also insisted that fuel was heated to produce an explosive atmosphere in the CWT ullage. The problem with this is C12H244 vapor molecules are very heavy and will not profuse throughout a tank except at Very High Temperatures.

In liquid state Jet A-1 is lighter than water but in vapor form the individual molecules are 8 times as heavy as water vapor molecules. This is why at normal temperatures water vapor mixes uniformly with air but C12H24 doesn't. Liquid fuel can neither burn or explode, only fuel vapor or mist can combine with oxygen in Air!

Note enclosure #2 (Pg. 43, F1617 Handbook of Aviation Fuels Properties) typical distillation curves for Jet A, JP4, and AVGAS. The figure shows a requirement to heat Jet A-1 to 178C or 352F to boil off the first full percent of Jet A-1! One percent of TWA's  residual Jet A-1 is 6 lbs. My calculations indicate a 2400 cubic ft tank at 13,700 ft altitude contains 27.5 lbs of oxygen (Little and Ives Complete Book of Science). In theory that would react with at least 10lbs of C12H24 in a high-energy fuel air explosion. 10lbs of Jet A-1 is 1.6% of TWA FL800's residual fuel.

Also note the 112C or 202F difference between Jet A-1 and JP4 required to vaporize that first one percent of each fuel.

This immense difference between the two totally different types of jet fuel is why No aircraft loaded with Jet A-1 has ever had or will ever have an internally ignited fuel tank explosion due to latent fuel vapor in the ullage.

I'm sure your advisors are well aware the Navy switched from JP4 to JP5 over 30 years ago followed by the commercial airlines turning to Jet A-1 and the Air Force from JP4 to JP8 (Jet A-1)

So how did TWA FL800's tank explode?   Note enclosure #3  (Pg. 76, Fig 35 Handbook of Aviation Fuels Properties)

At the 4100 meter level (FL800's Altitude) the flammability limits of Jet A-1 expand 76 percent driving the cold limit down 57° when the tank is severely agitated. This increase in flammability exposure is driven solely by mechanical misting of fuel into the ullage. The dotted line represents misting you could expect from Acrobatics.  So either the captain was demonstrating snap rolls to the passengers and your mystery ignition source ignited the tank or a military warhead detonated outside the tank misting the ullage and providing a high-energy fragment that exceeded auto- ignition thresholds inside the tank. I vote for the latter option. Warhead Engagements with aircraft frequently produce secondary fuel/air events which can be more detrimental to the target than the original blast.

Mr. Hall I am compelled to provide these cautions:

1. Stop trying to close this investigation with junk science sound bites! Your testimony before both Congress and the American people has been exceptionally misleading if not contemptuous in that:

A. You continue to liken TWA FL800 with aircraft mishaps that were fueled with JP4 or JetB. They are about as similar as a fuel oil hauler is to a dynamite truck! TWA FL800 stands alone! There are no peers!

B. You imply that if you can demonstrate FL800's CWT ullage was above LFL temperatures it would explain the explosion once your elusive ignition source is found. It would not! LFL-UFL boundaries only define when flame is possible at some point in the tank not explosive criteria. Your assumption would be true with lighter molecules such as propane or the lighter factions of gasoline that readily diffuse in air, C12H24 does not. In fact if a stable Jet A-1 tank could reach LFL temperatures and flame was introduced it would more probably be a contained event, burning it self out!

2. Stop ignoring major scientific impediment to your theory i.e.:

A. Properties of the Residual Fuel

The residual fuel in TWA FL800's tank was even less volatile then normal because it had been exposed to 1/5 atmospheric pressure for most of the prior Atlantic crossing. This did two things, it released any dissolved oxygen and allowed trace light hydrocarbon factions that might have been present to escape.

B. Heat Transfer Properties of Jet Fuel

Fuel is very difficult to heat. Heat transfers through Jet A-1 about 1900 times slower than aluminum, about 2 1/2 times faster than wool insulation, about equal to pine wood. (Little and Ives Complete Book of Science) So the reason you can hold onto a burning wooden match is one of the reasons TWA FL800's CWT never got close to LFL temperatures.

C. The Cold Soaked Aircraft

Everything on that aircraft not inside the heated pressure hull was exposed to 1/5 atmosphere pressure and minus 67°F at cruise altitudes for eight or more hours prior to turn around at JFK.

D. Cold Wing Tanks and Span wise Beam Heat Transfers

The beams that pass through the CWT also go through outer wing tanks full of cold fuel. If it were possible to heat the CWT enough to produce dangerous fuel vapors they would immediately condense on contact with these cool beams.

E. Temperature Lapse Rate Vs Declining LFL

See enclosure #4 (Pg. 76, Fig 35 Handbook of Aviation Fuels Properties). As the aircraft ascends the LFL drops because of declining atmospheric pressure on the fuel, however the temperature in the unpressurized ullage drops even faster because of the ideal gas law and the normal Adiabatic lapse rate.

The ideal gas law explains why a warm CO2 fire extinguisher discharges a freezing ice fog and why the temperature dropped rapidly in TWA FL800's CWT.

I've superimposed a lapse rate schedule (-3.5°F/Thousand Feet) over LFL figures. Notice two important points.  (1) the temperatures line already well outside the stable LFL line crosses the dynamic line prior to the event altitude!  Now notice the dynamic dotted line warning!  Only a high explosive warhead midair collision, ground impact or some other high-energy event could drive the dynamic line further to the left.   (2) notice also the temperature line verses JP4's LFL-UFL range. This explains the explosive atmosphere in the Iranian 747 that crashed while landing 21 years ago.  Had that aircraft had Jet A-1 aboard those pilots would have lived. It would have been just another routine lighting strike!

What really amazes me is your ability to spin this without any challenge from the media, how do they buy your hot fuel vapor theory without demanding temperature checks of B747 CWT ullages prior to routine flights from JFK to Paris everyday? For that matter why didn't you take fuel temperature samples of Paris bound B747's the first day you knew a fuel/air explosion had occurred on TWA FL800?  Temperature samples of B747 CWT residual fuel prior to take off would have immediately narrowed the investigation and provided surety of Flight Safety at no cost! Maintenance personnel take fuel samples from that tank every day to check water condensation. TWA crew chiefs have told me that fuel is always ice cold, even after 2 hour turnarounds at JFK!

3. Stop ignoring evidence of external explosions.

A. Eyewitness statements; (which by the way are evidence) of ascending objects and bright "white" flashes.

B. Physical Evidence;  Military warheads cause hundreds of P.S.I. over pressure, blowing in hatch gear doors, shearing off antenna, airscoops, even skin and major structure.  TWA FL800's nose gear doors (well forward of the CWT) were (1) found in the RED ZONE (came off very early) and (2) the hinges failed from the doors being pushed in. This is solid physical evidence, "One of the Smoking Guns."   Why do we hear about this only now, 14 months after the fact?

Mr. Hall I hope I have made myself clear this time, not withstanding that, my original protests and recommendations remain as before.


W. S. Donaldson

cc. Mr. Louis Freeh, Director, Fedral Bureau of Investigations

Mr. Barry Valentine, Acting administrator, Federal Aviation Administration

Senator Slade Gorton, Chairman, Subcommittee on Aviation

Representative John Duncan, Jr., Chairman, Subcommittee of Aviation

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