Title: JIM HALL - REGARDING TWA FLIGHT 800 FINAL REPORT
Author(s): JIM HALL, CHAIRMAN, NTSB
Source: FDCH Political Transcripts, 08/22/2000
Place of Event: NEWS CONFERENCE TRANSCRIPT
AUGUST 22, 2000
JIM HALL, CHAIRMAN NTSB CHAIRMAN
[*] (JOINED IN PROGRESS) HALL: ... many private citizens
who made
valiant efforts in the immediate hours and days after
the aircraft
went down. I would also like to thank the Coast Guard,
the Navy, the
FBI, NOAA, and the many other state and federal agencies
that assumed
major roles in the search and recovery effort. I would
like to note
the encouragement and support we have received from the
White House
and Congress in providing the resources needed to conduct
what has
become the most extensive, complex and expensive investigation
in the
Safety Board's 33 year history.
From the beginning, the scope and dimensions of this investigation
have been extraordinary. The salvage effort, organized
by the Navy,
one of the largest diver-assisted salvage operations ever
conducted,
extended from July to November, 1996.
The Navy divers worked in very difficult and dangerous
conditions and,
for a time, their efforts had to be halted because of
the onset of the
Atlantic hurricane season.
When the diving operations were completed, there followed
months of
work by contracted fishing trollers that scoured hundreds
of miles of
the ocean floor.
In the end, we recovered the remains of all 230 victims,
and more than
95 percent of the aircraft. The reconstruction of the
93-foot segment
of the fuselage, including the center wing fuel tank,
was unique both
in size and scope. More than 30 people worked meticulously
for many
month to sort through innumerable pieces of wreckage and
assemble the
wreckage in an effort to better understand what happened
to flight
800.
The number of organizations, public and private, that played
a
significant role in this investigation is extensive. I
want to pause
for a few minutes, so you can see the almost 500 names
of those
entities and individuals that contributed to the investigative
process. I direct your attention to the screens in front
of you.
(BREAK IN AUDIO FEED)
HALL: ... to study the temperatures and environment inside
the
aircraft's center wing tank. We also conducted extensive
research into
the composition and explosive characteristics of jet A
fuel. In
addition, we conducted tests and computer simulation work
to study
flame and pressure propagation in the center-wing tank.
Earlier on in the process, investigators began looking
at what roll
electromagnetic interference from external emitters or
sources
internal to the aircraft may have played in the crash.
The investigation also included the most extensive radar
data study in
the board's history, including a review of several hundred
thousand
radar returns from nine radar locations in five states.
The investigative team also spent a great deal of time
organizing and
carefully analyzing the summaries of witness interviews,
the Federal
Bureau of Investigation provided to the board.
We will be reviewing the work done by the witness group
and many of
the others in the course of this meeting. All of the investigative
work undertaken as part of this investigation, was extremely
complex.
Because of the need for precision, and in some cases,
the danger posed
to those performing the test, the work had to be painstakingly
done to
make sure that it was done properly, safely and accurately.
And of course, it was not inexpensive. We are fortunate
to secure the
assistance of a broad array of institutions, including
the Department
of Defense laboratories at Wright Patterson Air Force
Base, and the
Navy's China Lake and Patuxent River facilities. Important
work was
also done at NASA's Langley Research Center and the Sandia
Laboratories, among others.
We also contracted with private institutions, such as the
California
Institute of Technology, and the University of Nevada-Reno,
and
various specialties to conduct research.
Experts from other countries, including the United Kingdom,
Norway and
Canada, also assisted us. And the French aviation authorities
participated under the terms of the Convention on International
Civil
Aviation.
Much has been learned over the course of the past four
years. And the
five board members seated before you will be examining
and discussing
the results of the staff's work during this sunshine meeting.
I must emphasize that, over the next two day, you will
observe some
extremely technical discussion about the issues raised
in the
investigation. In preparation for this meeting, the board
members each
read the 684-page report and the 177 pages of information
that were
provided in party submissions.
The extensive record of this investigation now approaches
some 15,000
pages, and is available to everyone in the board's public
docket. The
investigative group's factual reports can also be found
on our Web
page, the other supporting documentation is available
in CD-ROM
format.
During the course of this investigation, the board received
a great
number of suggestions and comments from many individuals
and
organizations on possible causes of the crash of flight
800, and
recommendations for possible lines of investigation.
Much of this commentary has been well-informed and we appreciated
receiving it. Safety board staff has reviewed all of this
material and
took those ideas that appeared to have a scientific basis
and offered
a reasonable line of inquiry into account as the accident
investigation progressed.
In the early months of the investigation, it became clear
that an
explosion of flammable vapors in the aircraft's center-wing
tank
initiated the break-up and subsequent crash of Flight
800.
In December, 1996, based on the board's conclusion, that
heated
flammable vapors in the aircraft fuel tank poses a serious
risk to
safe flight, the board recommended that the Federal Aviation
Administration study design changes to deal with this
problem and, in
the interim, they require operational exchanges to enhance
safety. In
April, 1998, the board issued another set of recommendations
focused
on aircraft wiring and the fuel quality -- quantity indication
system.
During this meeting, we will be assessing what has been
done in
response to those recommendations, as well as what remains
to be
accomplished.
More broadly, the flight 800 investigation has uncovered
and focused
the attention of the aviation community on some very important
safety
issues: fuel tank protection; the vulnerability of aircraft
wiring;
and a number of aging aircraft issues.
We will pursue each of these items in some detail over
the next two
days.
This is a lot of ground to cover, but before moving ahead,
I would
like to make one additional comment. I know that. at the
outset, many
believe that the crash of flight 800 was caused by a criminal
act and,
for many, the efforts of the times, the ongoing court
trials and the
aftermath of the World Trade Center bombings in New York,
and the
heightened concern about terrorism at the 1996 Olympic
games in
Atlanta, seemed to lead a certain credence to the notion.
Certainly, the nature of the event, and its rarity, led
some to
question whether the crash of flight 800 was really an
accident. As
many of you know, a substantial law enforcement investigation
was
conducted in parallel with the safety board's investigation.
After conducting a thorough investigation, the FBI suspended
its
investigation in November, 1997, indicating that no evidence
had been
found to indicate that a criminal act was the cause of
the tragedy of
TWA Flight 800.
Despite this finding, by our nation's law enforcement agency,
the
Federal Bureau of Investigation, some have urged the safety
board to
assume, in effect, a law enforcement role, to prove or
disprove, their
assertion that the crash of flight 800 was the result
of a bomb or a
missile. That is beyond this agency's mandate and authority.
Our focus is safety. Our people are aviators, engineers
and
scientists. I believe some of the best in the world. But
they are not
criminal investigators.
However, even though our law enforcement -- even though
our employees
are not law enforcement personnel, they examined every
piece of
wreckage, for any physical evidence that the crash --
that the crash
of flight 800 could have been caused by a bomb or amissile.
Had we found such evidence, we would have immediately referred
the
matter back to the appropriate law enforcement agencies
for their
action.
Let me state unequivocally, the Safety Board has found
no evidence. To
the families of flight 800, I would like to add this comment.
It is
unfortunate that a small number of people, pursuing their
own agendas,
have persisted in making unfounded charges of a government
cover-up in
this investigation. These people do a grievous injustice
to the many
dedicated individuals, civilian and military, who had
been involved in
this investigation. Some 75 NTSB members have participated
in this
investigation. I'll pause while their name are listed
on the screens
in front of you.
(BREAK IN COVERAGE)
BERNARD LOEB, DIRECTOR NTSB OFFICE OF AVIATION SAFETY:
And, indeed,
that massive effort symbolizes the extent to which this
investigation
has gone, and leaving no stone unturned.
Al Dickinson, the investigator in charge, will be discussing
the
on-scene portion of the investigation in his opening remarks,
so I
will not go into detail about that at this time.
What I am going to do is to summarize the significant findings
of our
investigation. This will be just an overview. More detailed
explanations will be provided by investigators during
their individual
presentations over the next two days. But I think an overall
summary
of what you will be hearing would be valuable to put things
in
context.
First, we knew almost immediately after the accident that
TWA Flight
800 had experienced an in-flight breakup. This was strongly
suggested
by the radar data. There was a loss of transponder returns,
and the
primary radar returns indicated that pieces had departed
the airplane
and were fairly widely dispersed in the ocean.
The wreckage recovery locations made it evident relatively
early in
the investigation that the in-flight breakup was initiated
by an event
in the area of the fuselage near the forward part of the
center wing
tank. Specifically, pieces from the forward part of the
center wing
tank and adjacent areas of fuselage were recovered from
the
westernmost portion of the wreckage field, the portion
of the wreckage
field closest to JFK Airport, from where Flight 800 took
off. This
first wreckage area is referred to as the Red Zone.
The recovery of the pieces from the Red Zone indicated
that they were
the first pieces to separate from the airplane. The nose
portion of
the airplane was found further to the east and what was
labeled the
Yellow Zone, indicating that this portion of the airplane
separated
later in the breakup sequence. And most of the remaining
wreckage was
found in the eastern-most portion of the wreckage field
farthest from
JFK, which was labeled the Green Zone.
Further, analytical studies of the trajectories of the
departing
pieces of the airplane were consistent with the wreckage
recovery
findings. This basic evidence, the radar data and the
wreckage
recovery locations, indicated that the airplane broke
up inflight and
that the breakup initiated in the area of the fuselage
near the
forward part of the center wing tank. On the basis of
this initial
information, we considered several possible causes for
the initiation
of the in-flight breakup: a structural failure and decompression;
a
detonation of a high-energy explosive device, such as
a bomb or
missile warhead; and a fuel/air vapor explosion in the
center wing
tank.
We found no evidence that a structural failure and decompression
initiated the breakup. A thorough examination of the wreckage
by our
engineers and metallurgists did not reveal any evidence
of fatigue,
corrosion or any other structural fault that could have
led to the
breakup.
As a side note, I would like to mention that there was
absolutely no
evidence of an in-flight separation of the forward cargo
door, one of
the many theories suggested to us by the members of the
public. The
physical evidence demonstrated that the forwardcargo door
was closed
and latched at water impact.
We also considered the possibility of a bomb or missile.
However,
high-energy explosions leave distinctive damage signatures
on the
airplane structure, such as severe pitting, cratering,
hot gas washing
and petalling. No such damage was found on any portion
of the
recovered airplane structure. And as you know, more than
95 percent of
the airplane was recovered.
Our investigators, together with many outside participants
from the
parties to the investigation, closely examined every piece
of
recovered wreckage. All of the participants agreed that
none of the
wreckage exhibited any of the damage characteristic of
a high-energy
explosion. That is, of a bomb or a missile.
Further, no missing portions of fuselage were large enough
to
represent the entry of a missile. You may have noticed
that some of
the photographs of the reconstruction show what appear
to be several
large missing areas, such as those that are shown on the
screen now.
However, almost all of the fuselage structure in these
areas is
actually attached to the adjacent pieces but has been
folded back or
crushed in such a way that it does not cover its original
area.
Therefore, these large gaps that appear to exist in the
reconstructed
fuselage do not represent areas of damage that could have
been caused
by a missile.
In addition, we found no localized area of severe thermal
or
fragmentation issues and no localized severe damage or
fragmentation
of the seats, as such as would be expected if a high-energy
explosive
device had detonated inside the airplane. The injuries
to the
occupants and the damage of the airplane were fully consistent
with an
in-flight breakup and subsequent water impact. In light
of all this
evidence, a bomb or missile strike has been ruled out
as an initiating
event of the in-flight breakup.
The FBI did find trace amounts of explosive residue on
three pieces of
the wreckage. However, these three pieces contain no evidence
of
pitting, cratering, hot gas washing or petalling, which
would have
been there had these trace amounts resulted from abomb
or missile.
Further, these trace amounts could have been transferred
to these
pieces in various ways. For example, in connection with
ferrying
troops during the Gulf War or during dog-training explosive
detection
exercises that were conducted on the accident airplane
about one month
before the accident.
There is also the possibility that the explosive residues
could have
been deposited on the wreckage during or after recovery
operations as
a result of contact with the military personnel ships
and vehicles
used during those operations. We don't know exactly how
the explosive
residues got there, but we do know from the physical evidence
I've
just discussed that the residues were not the result of
the detonation
of a bomb.
Unlike the other two scenarios I've just mentioned, a structural
failure or high-energy explosive, the third scenario we
considered, a
Jet A fuel/air explosion in the center wing tank, was
consistent with
the physical evidence. Specifically, as I've already mentioned,
the
wreckage recovery locations indicated that the first pieces
to depart
the airplane were from in and around the front of the
center wing
tank.
Based on these recovery locations and damage characteristics,
the
investigative group led by Jim Wildey, known as the Metallurgy
and
Structure Sequencing Group, determined that the earliest
event in the
breakup sequence was an overpressure inside the center
wing tank that
caused structural failure of its forward part. This overpressure
event
started the breakup sequence that ultimately resulted
in the
destruction of the airplane.
I would like to emphasize that all of the parties to the
investigation, as well as numerous outside experts and
researchers,
have agreed with the findings of the sequencing group.
Jim Wildey will
be explaining the breakup sequence a little later today.
The point I would like to make now is simply that the initial
breakup
sequence and early departure of pieces from in and around
the center
wing tank clearly indicate that the breakup was initiated
by an
overpressure inside the center wing tank. Given that there
was no
high-energy explosion in this or any other area of the
airplane, this
overpressure must have been caused by a fuel/air explosion
inside the
center wing tank.
However, questions were raised early in the investigation
about
whether the conditions necessary for a fuel/air explosion
could have
existed inside the accident airplane's center wing tank;
and also
whether a Jet A fuel/air explosion could generate sufficient
pressure
to break apart the fuel tank and destroy the airplane.
To address the first issue, the Safety Board conducted
flight tests at
JFK in July of 1997 using a 747 leased from Evergreen
Airlines.
Several test flights were conducted under conditions similar
to those
experienced by Flight 800. The fuel/air vapor inside the
center wing
tank was measured at various locations during the flight.
The
temperatures inside the center wing tank at the altitude
at which the
accident occurred, approximately 13,800 feet, ranged between
101 and
127 degrees Fahrenheit. Extensive work done by scientists
at the
California Institute of Technology showed that the Jet
A fuel under
the conditions experienced by Flight 800 would have been
flammable at
these temperatures. In fact, their work demonstrated that
fuel vapors
under those conditions may have been flammable at temperatures
as low
as 96 degrees. Dr. Joseph Kolly will be talking more about
this
research later today.
The second issue, whether an explosion of Jet A fuel could
generate
sufficient pressure to break apart the fuel tank and destroy
the
airplane, was also put to rest in the investigation. Laboratory
tests
and quarter-scale tests under the direction of scientist
at the
California Institute of Technology demonstrated the pressures
exceeding the structural limitations of the forward portion
of the
center wing tank were produced from the combustion of
a Jet A fuel/air
mixture similar to the one that existed in the center
wing tank of TWA
Flight 800.
(END AUDIO FEED)
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Source: FDCH Political Transcripts.
Item Number: 101814474880
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