Dan's Papers - Long Island
Flight 800's Center WingTank
Pilot Who Flew The Plane Before Fateful Flight
Questions Official Conclusions
By Jerry Cimisi
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 psi.
"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 discrepancy."
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 you’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 wing.
"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 be located."
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.
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