04-21-04GATC—Wichita, KS FAA R&D Efforts Leading to Fuel Tank Inerting General Aviation Technology...

04-21-04GATC—Wichita, KS

FAA R&D Efforts Leading to Fuel Tank Inerting

General Aviation Technology Conference & ExhibitionWichita, KSApril 21, 2004

Steve SummerProject EngineerFederal Aviation AdministrationFire Safety Branch, AAR-440


“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


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


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

Fuel

Oxygen

Ignition


Inerting Requirements

Controlled parameters:• Pressure (altitude)

• Fuel temperature/flammability

• Oxygen concentration

• Ignition source

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


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


FAA OBIGGS


Complete OBIGGS Development and Validation of Concept

0

5

10

15

20

25

0 20 40 60 80 100 120

Time (min)

Oxy

gen

Co

nce

ntr

atio

n (

% v

ol)

0

10

20

30

40

50

Alt

itu

de

(kft

)

Flight Test Data

Model Data

Altitude

Single Membrane Test

Fire Safety Oversaw Construction of System, Installed it in Full-Scale 747SP

Ground Test Article and Tested Capabilities

Fire Safety Tested System with Airbus on an A320

Concept was Validated and System Capabilities Predicted


Ongoing System Validation & Furthering of Concept

December 2003/May 2004: FAA/NASA 747 SCA Flight test• FAA’s 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)


Summary FAA R&D 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 R&D process (IASFPWG) has enhanced the FAA’s R&D work

Continued development of the basic concept by industry has the potential to yield even smaller, more efficient systems in the near future.


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

04-21-04GATC—Wichita, KS FAA R&D Efforts Leading to Fuel Tank Inerting General Aviation Technology...

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