Associated Retired Aviation Professionals
Post Office Box 90, Clements, Maryland 20624 USA

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 

"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 

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 

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 

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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