TWA800's reconstruction

 Cargo Door Area

July 17, 2008 - FAA Announces New Safety Measure Prompted By 1996 Crash
UNITED STATES - It took 12 years, but the Federal Aviation Administration is finally ready to make a major safety change resulting from the investigation into the TWA flight 800 crash.

Investigators concluded that an explosion in the fuel tank of the 747 brought the plane down off Long Island, shortly after takeoff from JFK.

The FAA will make its announcement today at the hangar in Virginia where the wreckage of Flight 800 is stored.

USA Today quotes federal and industry officials who say the government will require that jet fuel tanks be upgraded so that heated gas vapor is flushed out of fuel tanks in flight.

The big center fuel tank in 747s is particularly vulnerable to these fumes. More than 3,000 jets are affected, but airlines will be given up to 10 years to make the upgrades. 

FAA Issues Fuel Tank Flammability Rule

Jul 16, 2008


The U.S. FAA--nearly 12 years after the inflight breakup of TWA Flight 800--has issued a final rulemaking aimed at eliminating the risk of catastrophic fuel tank explosions.

Airlines, already staunching the flow of red ink, now face budgeting in the cost of retrofitting aircraft with the systems in the next decade.

The rule, long-awaited by the National Transportation Safety Board, is aimed at preventing another TWA Flight 800 accident. On July 17, 1996, Paris-bound Flight 800, a Boeing 747-131, broke up in flight shortly after departure from New York Kennedy (JFK) Airport, and all 230 people onboard were killed.

Investigators determined that the breakup was probably caused by the explosion of flammable vapors in the center wing fuel tank. The source of the ignition was never determined, but investigators thought it likely that wiring in the fuel quantity indication system caused a short circuit.

Since that day, the reduction of fuel tank flammability has been on the NTSB's Most Wanted List of safety recommendations. The FAA issued 70 advisory circulars and 100 airworthiness directives aimed at mitigating risks, most of which aimed at reducing sources of ignition.

In May 2001, the agency issued SFAR 88 (Special Federal Aviation Regulation) aimed at preventing ignition sources, but did not issue a proposed rule until November 2005.

The July 16 final rule follows the proposed rule, with some exceptions. It would require Boeing and Airbus passenger aircraft with heated center wing tanks (HCWT) and manufactured before 2009 to be retrofitted with a flammability reduction means (FRM), such as a fuel tank inerting system, or ignition mitigation means (IMM), such as polyurethane foam. (A fuel tank inerting system replaces oxygen in a fuel tank with an inert gas, such as nitrogen, to reduce risk of flammability. For the full 223-page rule, go to

In addition, the rule requires that an FRM or IMM be installed on passenger and cargo aircraft with HCWTS manufactured in the 2009-2017 period. Boeing 717, 727 and certain 767 and 777 aircraft, as well as Airbus A321, A330-200 and A380 aircraft, are excluded.

Cargo aircraft are excluded from the retrofit requirement. However, If an FMM/IMM-equipped passenger aircraft is converted to cargo aircraft, the cargo operator would be required to keep the system operational.

The FAA estimates total compliance cost of the rule at $1 billion, $975 million for air carrier passenger aircraft and $37 million for production cargo aircraft, over a 35-year period.

The final rule indicates that 2,732 passenger aircraft would require retrofit, with kit costs ranging from $77,000 to $192,000, depending on aircraft type. Total retrofit costs would run $110,000 to 250,000 per aircraft, costs that, over time, would decline $10,000-17,000, according to the FAA.

In addition, 2,290 production passenger aircraft and 88 production cargo aircraft manufactured in 2009-2017 will be affected by the final rule.



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FAA Issues Fuel Tank Flammability Rule
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Investigators determined that the breakup was probably caused by the explosion of flammable vapors in the center wing fuel tank. The source of the ignition ...
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DOT Issues Final Rule On Fuel Tank Fire Suppression Systems
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The NTSB determined the airliner was brought down by an explosion caused by fumes in the 747's near-empty center tank. When it made that determination in ...
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The rule also requires airlines to retrofit 2730 existing Airbus and Boeing passenger planes over the next nine years with center wing fuel tanks with the ...
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from this link


DOT Issues Final Rule On Fuel Tank Fire Suppression Systems

Wed, 16 Jul '08

All New Planes Must Include Systems Within 2 Years

ANN REALTIME UPDATE 07.16.08 1300 EDT: Confirming earlier reports, on Wednesday the Department of Transportation issued a mandate requiring all new aircraft to include technology designed to significantly reduce the risk of center fuel tank fires within two years. In addition, passenger aircraft built after 1991 must be retrofitted with technology designed to keep center fuel tanks from catching fire.

"We want to do everything possible to make sure safety examiners wonít have to investigate another plane shattered by an exploding tank," said US Transportation Secretary Mary E. Peters during her announcement of the final rule, along with Acting FAA Administrator Robert Sturgell. "We canít change the past, but we can make the future safer for thousands of air travelers, and this rule does just that."

The Secretary -- speaking the day before the 12th anniversary of the crash of TWA Flight 800, which prompted the requirement -- said the new rule was needed to help avoid a similar incident. The rule requires aircraft to have technology to neutralize or eliminate flammable gasses from fuel tanks under the center wing of commercial passenger planes.

Peters noted in the wake of the TWA crash researchers with the Federal Aviation Administration developed a system that replaces oxygen in the fuel tank with inert gas, which effectively prevents the potential ignition of flammable vapors. Boeing also has developed a similar system.

"Todayís rule will add another layer of safety reducing the chance that the vapors in the tank will ignite, even if there is a spark," added Sturgell.

NTSB Chairman Mark Rosenker also lauded the DOT's action. "The NTSB congratulates the DOT and the FAA on this important safety achievement," he said. "From tragedy we draw knowledge to improve safety and today's announcement represents a significant step toward avoiding future aviation accidents of this nature."

Acknowledging strong protests over the past decade from airlines, which argued the system's cost was too expensive, Peters noted the prictag of installing the new technology would range from $92,000 to $311,000 per aircraft, depending on the aircraft's size. Peters (below) noted that's as little as one-tenth of one percent of the cost of a new aircraft.

US aircraft that will be retrofitted include approximately 2,730 aircraft -- including 900 Airbus A320 Family airplanes, 50 A330s, 965 Boeing 737s, 60 Boeing 747s, 475 Boeing 757s, 150 Boeing 767s and 130 Boeing 777s.

"I recognize that this is a challenging time for commercial aviation," Secretary Peters said. "But there is no doubt that another crash like TWA 800 would pose a far greater challenge."

Peters made the announcement while addressing accident investigators at the National Transportation Safety Boardís (NTSB) Training Facility in Virginia, where remains of the TWA Boeing are kept as an educational tool for safety investigators.

Original Report

0001 EDT: Using the wreckage of TWA Flight 800 as a backdrop, the Department of Transportation will announce Wednesday that nearly all commercial airliners operating in the United States must be fitted with fuel inerting devices within 10 years.

The FAA and National Transportation Safety Board announced the rare joint safety briefing Tuesday, but provided few details.

USA Today reports the DOT will make the formal announcement in the Virginia hangar housing wreckage from the Boeing 747-100 that exploded off Long Island on July 17, 1996, killing all 230 onboard. The NTSB determined the airliner was brought down by an explosion caused by fumes in the 747's near-empty center tank.

When it made that determination in 2000, the NTSB also stated most other large airliners were susceptible to such explosions, and recommended all jets be equipped with systems to stop fuel tank fires. That plan was sharply criticized by airlines, which said such measures would be prohibitively expensive.

A debate has raged ever since between government officials and airline representatives. A comparatively cheaper alternative to tank extinguishers was developed in 2002, in which tanks could be flooded with nitrogen to prevent explosive fumes from forming... but despite a 2004 FAA order calling for such systems to be installed within seven years, little has been done to enforce that rule.

The Office of Management and Budget reportedly approved the fuel tank rule last month, according to the paper. It will apply to all large airliners built after 1991 in commercial service.

FMI: Read The Final Rule