FAA R

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FAA RD Efforts Leading to Fuel Tank Inerting
General Aviation Technology Conference
Exhibition Wichita, KS April 21, 2004
Steve Summer Project Engineer Federal Aviation
Administration Fire Safety Branch, AAR-440
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The FAA is considering a Notice of Proposed
Rulemaking for later this year that would help
prevent fuel tank explosions by requiring that
new systems those that would reduce the
flammability of fuel tank vapors on the ground
and in flight be installed on those Boeing and
Airbus models whose air conditioning systems
could cause heating of center-wing fuel
tanks. -FAA Press Release, 02/17/04
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Background - Accident History

• 17 accidents between 1959 and present
• Three accidents in recent history
• 1990 737-300 Manila, Philippines, 8 Fatalities
• 1996 747-100 New York, United States, 230
  Fatalities
• 2001 737-400 Bangkok, Thailand, 1 Fatality
• Accident Similarities
• Heated Center Wing Tank (CWT)
• Hot day
• Long ground operations with packs running
• Empty (residual fuel) tank
• Explosion occurred on the ground/shortly after
  take-off
• Exact ignition source was never located

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Background Fuel Tank Protection

• For an explosion to occur, the fire triangle must
  be satisfied
• Sufficient fuel vapor
• Sufficient oxygen
• An ignition source
• Past attempts to preclude ignition sources from
  fuel tanks has had limited success
• Inerting looks to eliminate the risk by reducing
  the oxygen concentration

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Inerting Requirements

• Ignition tests conducted at the FAA to
  determine the Limiting Oxygen Content (LOC)

• Controlled parameters
• Pressure (altitude)
• Fuel temperature/flammability
• Oxygen concentration
• Ignition source

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OBIGGS System Development

• Hollow fiber membrane technology uses the
  selective permeation properties of certain
  materials to separate air into two streams, one
  nitrogen rich and the other oxygen rich.
• Materials are woven into hair-sized membranes and
  bundled by the thousands into a canister called
  an air separation module (ASM)

• Pressurized air is forced through the membrane
  fibers, allowing fast gases to escape through the
  membrane wall and the nitrogen rich stream to
  pass through

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FAA OBIGGS
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Complete OBIGGS Development and Validation of
Concept
Fire Safety Oversaw Construction of System,
Installed it in Full-Scale 747SP Ground Test
Article and Tested Capabilities
Concept was Validated and System Capabilities
Predicted
Fire Safety Tested System with Airbus on an A320
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Ongoing System Validation Furthering of Concept

• December 2003/May 2004 FAA/NASA 747 SCA Flight
  test
• FAAs OBIGGS system installed in aircraft pack
  bay 4
• Further concept study as well as operational
  variations tested

• Continuous CWT and wing tank flammability
  (hydrocarbon data being taken in-flight for first
  time)

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Summary

• FAA RD used existing technology in an innovative
  way to develop a near term, simple,
  cost-effective solution fuel tank flammability
  reduction
• System utilizing the FAA methodology can be
  developed using commercial aviation grade parts
  available immediately
• Industry involvement in the RD process (IASFPWG)
  has enhanced the FAAs RD work
• Continued development of the basic concept by
  industry has the potential to yield even smaller,
  more efficient systems in the near future.

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FAA Fire Safety Branch Websitewww.fire.tc.faa.gov