- It is no surprise to anyone on either side of the TWA
Flight 800 controversy that the National Transportation Safety Board declared
at its final, just concluded hearing that the doomed plane that exploded
four summers ago was brought down by an electrical spark which had ignited
vapors in the empty or near empty center wing fuel tank.
- Unfortunately, the NTSB said, its investigators have
not been able to locate the spark or wire that originated the explosion.
- Among the many who contest the NTSB scenario is the last
pilot to fly the 747 and live to talk about it.
- In a phone interview some days after the NTSB hearing,
now retired TWA pilot Al Mundo, who had brought the plane into New York
from Athens late on the afternoon of July 17, 1996, explained not only
the fuel system of the plane, but detailed his reasons why the center
wing fuel tank would not have been the initiating cause of the explosion
or explosions that destroyed Flight 800.
- "We had left Athens that Wednesday morning,"
said Mundo. "The center wing tank would have been full."
- The center wing fuel tank is just that: a tank of fuel
that is directly in the middle of the plane, beneath the passenger cabin.
- Before going into the reasons why the fuel in that tank
would not have been full on arrival in New York, Mundo explained the fuel
system of the 747.
- "There are four main tanks of fuel, and two reserve
tanks, to feed into four engines. If you're sitting in the cockpit, from
left to right, you have on the edge of the left wing, the number one
reserve tank. Then, in sequence, you have the number one main tank, number
two main tank, number three main tank, number four main tank, then on
the tip of the right wing, the number four reserve tank."
- Mundo went on to say that the fuel flow of the plane
is maintained so that the weight of fuel throughout the wing span will
be balanced. Fuel is normally fed from each tank to its corresponding
engine, although, said Mundo, when the combined fuel in the number one
main tank and its reserve, and the number four main tank and its reserve
equals 25,000 pounds (the fuel is measured in pounds, not gallons), cross
feeding fuel procedures are initiated.
- "We turn on both of the center wing tank fuel pumps.
The center wing tank has two pumps, which work at twice the capacity of
the other four main tank pumps; their fuel flow is at fifteen pounds
per square inch (psi), the center wing tank pumps put out fuel at thirty
- "The cross feed valves are open, which allow fuel
from the center wing tank pumps to go to the number one, two, three and
four engines. We shut off the pumps from the number one main and its reserve
and the number four main and its reserve. We leave the pumps on from
two and three as back up, though because they are working at a rate only
half that of the center wing tank, it's the center wing tank that is supplying
fuel to the engines. At that point the two and three main tank feed is
there as a backup. Anyway, at this point the center wing tank is supplying
fuel to all the engines.
- "Eventually, as the center wing tank burns down
to about 3,000-4,000 pounds of fuel, the fuel begins to feed from the number
two and three main tanks."
- When the fuel quantity in the center wing tank gets low,
a light for each pump begins to blink on the flight engineer's panels.
"When the light gets steady," said Mundo, "you turn off
the pump for that light.
- "Then you turn on the fuel/water scavenge pumps
in the center wing tank to drain any liquid remaining. "
- With the feed from the center wing tank now turned off,
all four engines are being fueled from the number two and number three
main tanks. At the point where there are about 25,000 pounds of fuel
in each of the main tanks (again, with number one main and reserve tanks
and number four and reserve tanks totalling 25,000 pounds each), so there
is an even balance across the wing. Cross feeding is terminated so that
main tank one and its reserve will be going into its respective engine,
number two into its respective engine and so forth.
- Mundo went on: "When the plane landed in New York,
the center wing tank guage in the cockpit would have read zero pounds.
It is possible that the underwing center wing tank fuel gauge could have
read 300 pounds, which would be about fifty gallons. This is not an unusual
- In the first few days after the Flight 800 investigation
Mundo asked a TWA official what exactly the fuel use log had shown in regards
to the quantity of fuel in the center wing tank upon arriving in New
York. "He told me," Mundo said, "that the log, which is
placed in the Flight Document Envelope and normally kept for ninety days,
could not be found. This was an abnormality."
- He added that whatever level of fuel existed in the center
wing tank at that time would not be entirely composed of fuel. "All
fuel contains some water. It's the same with the gas in your car. Fuel
is 6.7 pounds per gallon; water is heavier, 8.34 pounds, so the water
goes to the bottom of the tank. This combination of water and fuel is
what the scavenger pumps transfer to the number two main tank."
- Mundo said, "When 747's undergo a heavy maintenance
check, and the nose wheel strut is deflated which tilts the plane downward,
all the liquid in the center wing tank fuel goes to the front of the
tank where it is drained out. The amount drained is usually close to fifty
gallons or around 300 pounds."
- In sum, the center wing tank of the plane that was about
to become Flight 800 was empty or nearly empty before leaving New York
in the late afternoon prior to its evening takeoff to Paris.
- Because of prevailing winds, planes usually carry more
fuel when going west than when going east. "And then," said Mundo,
"you also have to consider the distance youâ ¬!"re
travelling. Athens to New York is a lot farther than New York to Paris."
- Now we get to one of the crucial points of the NTSB theory
about the volatility of the center wing tank. Mundo said, "There
is the assumption by the NTSB that the fuel was heated by the air conditioning
packs below the plane to a temperature that caused the fuel and fuel vapors
to reach an explosive level."
- This is an assessment with which the majority of the
media concur. A New York Times article from Wednesday, August 23, the day
after the NTSB hearing began, stated, "the nearly empty tank, which
had been heated to an explosive state while the twenty-five year old
jet sat baking in the sun for nearly three hours before taking off."
- Mundo said, "I left two of the packs running, as
was common practice." He added that with the flight time between Athens
and New York at about ten hours, "for at least nine and half hours
the metal of the tank was, at the altitude we had been flying, exposed
to temperatures that were about minus fifty-five degrees Celsius. Now
metal will cold soak when your car is outside through the night in January
you know it takes the metal some time to warm up.
- "This is something they should have tested, but
they didn't, exactly. The NTSB flew a plane across the continental United
States, trying to duplicate the conditions of the Athens to New York
flight, but in the summer the air over the land would be warmer than over
the North Atlantic and of course the plane would not be in the air for
as long as on an Athens to New York run. Nobody knows exactly what the
temperature in the fuel tank was when Flight 800 took off from New York.
Commander Donaldson took a reading from a 747 at Kennedy the summer after
the accident, and he found the temperature of the fuel drained from the
center wing tank which had been on the ground an equivalent amount of
time as 800 was, to be a degree above the ambient [outside] tempertaure."
(Retired Navy Commander William S. Donaldson has been a longtime critic
of the government's investigation of Flight 800.)
- "Flight 800 took off for Paris at about 8:15 p.m.
on the evening of July 17, 1996. A nearly empty tank has more fuel vapor
than a tank that is full. Government investigators speculate that the
vapor-ridden center wing full tank was ripe for an explosion instigated
by the as-yet unfound electrical source.
- But Mundo pointed out that the center wing fuel tank
is vented to relieve the pressure inside the tank. "With an aircraft
in flight," Mundo said, "you have a Venturi effect over the
vent outlet. The more the speed, the less the pressure. When you're in
a car and someone's smoking and you open a window, the air pressure outside
is less than the pressure inside and the greater pressure inside pushes
the air outside; the smoke will be sucked out of the car. The air rushing
outside the plane would create a great suction that should have decreased
or eliminated any buildup of vapor in the tank." _____
- Former TWA pilot Al Mundo then talked about another aspect
of the electrical spark theory: on Good Friday, 1995, when he was flying
the plane that would become Flight 800 in July, 1996, the aircraft was
struck not once but twice by lightning.
- The plane did not explode.
- "We were descending into Rome. We were at about
13,000-11,000 feet. There were two strikes of lightning, about three minutes
apart. There was a loud bang, and a yellow flash; initially there was
no indication of anything wrong in the cockpit."
- But a photoelectric cell activated an inerting gas whose
purpose was to smother any fire or smouldering that could be caused by
an electrical spark. This was done on the first lightning strike.
- Mundo said, "Upon landing it was discovered there
was not only substantial damage to the right wingtip, it was also found
that an electrical charge had gone all the way into the wing area, causing
circuit breakers in the cockpit to pop and the wheel brake temperature
indicators to register full scale when the brakes had scarcely been used.
It is quite evident from this that a strong surge of electricty went through
- "The damage incurred was extensive. The plane was
out of service for a week," said Mundo.
- But despite the damage that had been inflicted by the
two lightning strikes, the plane was able to land safely. The inference
is obvious: if the plane that expolded fifteen minutes out of JFK in
the summer of 1996 was brought down by an electrical spark igniting the
center wing fuel tank, why didn't two lightning strikes, which would certainly
supply infinitely more voltage to the electrical system of the plane than
the theorized stray spark, cause the aircraft to be blown apart?
- Early on in the Flight 800 investigation, Mundo learned
that there had been sooting found on the right wing vent system. "It
seemed strange to me that if the explosion was initiated by the center
wing tank, why would there not be sooting on both sides of the wing?
I contacted personnel in the investigating team and suggested they check
those records from the 1995 flight to determine if the sooting came from
the lightning strikes. I was later informed that the records could not
- Mundo was questioned by investigators "about five
days after Flight 800," he said, but the extent of the questioning
was solely on the character of the Athens to New York Flight. The former
pilot continues to feel that government investigators have not pursued
the obvious lines of inquiry raised above or, if they have, such tests
or studies have not been made public.
- © 2000 William S. Donaldson III. All rights reserved
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