By LESLIE MILLER, Associated Press Writer
Wed Jul 6, 5:55 PM ET
WASHINGTON - Nearly nine years after a fuel
tank explosion caused the fatal crash of TWA
Flight 800, safety officials say little has been
done to reduce the flammability of vapors in
aircraft fuel tanks.
National Transportation Safety Board
executive director Dan Campbell said Wednesday
that while much more is known about how to
prevent fuel vapors from exploding, little has
"We're not significantly different than we
were in '96," Campbell said during a briefing
Boeing and the FAA disagree. Both point to
progress in designing safer systems, which are
based on an FAA prototype, as well as plans to
begin producing them next year.
FAA spokesman Greg Martin said the agency has
moved aggressively to eliminate the factors that
can cause jet fuel vapors to explode: sparks (or
flames) and a deadly combination of concentrated
oxygen and fuel.
"Although a rigid formal rulemaking process
takes time, we've moved aggressively to remove
both ignition sources and flammability levels,"
Boeing spokeswoman Liz Verdier said aircraft
manufacturers are working to reduce fuel tank
explosions even though they're extremely
"They're getting more and more rare because
the industry constantly works on safety,"
Campbell acknowledged that the FAA has
reduced sources of ignition that can cause fuel
vapor explosions. The FAA has ordered airlines
to make more than 60 changes to eliminate
potential ignition sources, such as faulty
In the past 15 years, there have been three
fuel tank explosions: the TWA accident,
resulting in 346 deaths, and two in Asia while
the aircraft were on the ground.
All 230 people aboard TWA Flight 800 perished
when the Boeing 747 crashed off the coast of
Long Island, N.Y., on July 17, 1996, en route to
The NTSB said a spark in the wiring ignited
vapors in the Boeing 747's partly empty fuel
tank. Air conditioning units underneath the fuel
tanks are believed to have heated the vapors
inside the tank — making them more vulnerable to
explosion — during the plane's two-hour delay at
New York's John F. Kennedy International
After the accident, FAA researchers developed
a system called "fuel tank inerting" that
reduces the oxygen in the fuel tanks, making an
explosion much less likely.
"We did not take 'no' for an answer when
initial technical reviews said that fuel
inerting systems would be too costly and too
heavy," said the FAA's Martin.
The system pumps air flowing from the plane's
engine into yard-long canisters. A ropelike
substance in the canisters filters oxygen and
water from the air. The result, a nitrogen-rich
mixture, is pumped into the fuel tanks. The
filtered-out water and oxygen is dumped off the
Campbell acknowledged that Boeing is
designing new planes with fuel inerting systems,
but said the safety board is frustrated with the
lack of progress on requirements for the
existing fleet to be retrofitted. The FAA
estimated that about 3,800 planes in the United
States will need to have the new systems
installed at a cost of between $140,000 and
$220,000 per aircraft.
But the Air Transport Association, the
lobbying group that represents major airlines,
said it's not possible to assess the
effectiveness of the fuel inerting systems
because the FAA hasn't yet approved any for
According to Boeing's schedule, 737s and 747s
with the systems will go into service in the
middle of next year, followed by 777s and 767s
in early 2007, Verdier said.
Shortly after the new jetliners go into
production, Boeing will be offering to retrofit
existing aircraft with fuel inerting systems,
Verdier said. Retrofits for the 757, which is no
longer in production, will be available sometime
in early 2007, she said.
The 787, a new long-range plane dubbed the
Dreamliner, has already been designed with a
fuel inerting system and will start flying in
2008, Verdier said.
Airbus, on the other hand, says its fuel
tanks are safer because they aren't near heat
sources and have no high-voltage wires running
"Should the rules change, we will continue to
work with the authorities, and evolve as
necessary pending FAA rulemaking," Airbus
spokeswoman Mary Anne Greczyn said in an
The NTSB's Campbell also criticized lack of
progress on moving air conditioning units away
from fuel tanks, which also reduces the
likelihood of an explosion.
In a small percentage of cases, airlines now
use ground units to cool planes before they take
off, NTSB investigators.