November 15 th - 18 th, 2004 FAA Fire and Cabin Safety Conference Lisbon, Portugal Auxiliary Tank Testing and In-Flight Facility Development Michael Burns Fire Safety Research Federal Aviation Administration William J. Hughes Technical Center

2 Background Three major accidents involving center wing tanks (CWT) –March 2001, Thai Airways International, Boeing –July 1996, TWA flight 800, Boeing –May 1990, Philippine Airlines, Boeing FAA seeks it’s flammability reduction rule since 1997 –Two unsuccessful industry rulemaking advisory committee working groups FAA developed a demonstration fuel tank inerting system Installed and operated on several test transport aircraft –Uses air separation modules (ASM) and a dual / variable flow methodology Unique methodology allowed for simple, lightweight, reliable onboard nitrogen generation

3 Center Wing Tank Inerting Research Recent CWT testing with NASA, Airbus and The Boeing Company –FY01- FY04 testing and validation of CWT inerting methodology –In-flight measurement of fuel tank flammability Excellent results but little work has been done to study the affect of auxiliary tank operations on CWT New research facility at FAA WJH Technical Center –Construction scheduled for winter, 2005 Facility being designed to study fuel tank inerting and flammability –Real-time CWT operational simulation, full-scale testing, and model validation

4 Center Wing Tank Inerting Facility

5 Center Wing Tank Inerting Facility – cont. Initial use to further study the affect auxiliary fuel transfer has on an inert CWT –Ullage oxygen concentration changes due to fuel transfer –Purge cycle effects once the auxiliary tank is empty –Auxiliary tank refueling effects Facility will house a full-scale CWT and auxiliary fuel tank –Simulate altitude as well as engine fuel burn –Thermocouples, pressure transducers and gas sample ports for gas analysis to allow for testing –Measure nitrogen generating system parameters

6 Facility Overview

7 Facility Overview – cont. Approximately 26’ x 40’ Interior Communication & Signal Raceways Pumps (3) –Vacuum Hi-capacity pump with closed loop cooling system Capable of simulating a 40,000 foot altitude (approx. 2 psia) –Fuel (P 1 ) – Electronically Controlled, Modulating Engine fuel burn simulator Variable frequency drive fuel flow controller simulates taxi, take off, climb, cruise & descent Fuel flow meter with digital output Capable of flowing 85 GPM maximum fuel flow. –Fuel (P 2 ) – Fixed Used to refuel the CWT / aux. tank when required Plumbed to a 10K gallon fuel vault

8 Facility Overview – cont. Control Room –Environmentally controlled –Houses all the controls, analyzers, computer and data acquisition equipment –8’ x 8’, mounted on a raised concrete slab Safety Features –Spill Protection – Containment pit with sump Foundation contains curbing that is approx. 14’ x 24 x 18” Approximately 500 cubic feet of volume to contain any accidental spillage of fuel –Fire protection –Over pressure relief panel system

9 Facility Overview – cont. Vacuum pump evacuates chamber Altitude controller –PID Controller –Modulating Valve –Pressure Transducer

10 Facility Equipment 737 CWT Tank origin –Salvaged from an Air Canada aircraft in March 2003 Tank Dimensions / volume –Approx 12’ x 14’ x 3’ (or 500 CuFt in volume) Reinforcing the CWT –Exterior bracing was applied around the tank structure and fastened to the tank wherever possible –Columns were installed in each bay internally to offset compression forces exerted on the tank while applying a vacuum

11 Facility Equipment – cont. 737 CWT

12 Facility Equipment – cont. 737 CWT Vent configuration –Internally the tank is vented in the most forward bay as well as the aft bay –The left & right vent stringer was modified with a flange connection –These 2 connections will be joined together with plumbing and routed to the facility vacuum system Engine burn simulation – fuel feed tubing –Facility tubing will be tied into the fuel boost pump feeds on the tank

13 Facility Equipment – cont. 737 CWT Left Fuel Feed Tubing (Bay 3) Right Vent Tubing (Bay 2)

14 Facility Equipment – cont. Auxiliary Fuel Tank Tank origin –US Airways surplus auxiliary fuel tank Tank Dimensions / volume –Approx. 8’ x 4’ x 3’ –Approx. 475 Gallons of fuel Single tank configuration –Also known as a “Master Fuel Cell” –Contains a dry bay that houses all the valving associated with the system Cabin Tube –The fuel cell is pressurized during flight using cabin pressure –In facility, shop air used to simulate normal tank operation

15 Facility Equipment – cont. Auxiliary Fuel Tank

16 Instrumentation 737 CWT / Auxiliary Tank Thermocouples –All thermocouples are “T” type –25 total installed throughout the CWT –4 total installed throughout the Auxiliary Fuel Tank Gas sample tubes – (FAS, OBOAS) –All sample tubing is made up of PFA material and ¼” in diameter –6 total mounted throughout the CWT –2 total mounted throughout the auxiliary fuel tank NEA Inerting Manifold –Single injection nozzle made of PFA tubing

17 Instrumentation – cont. 737 CWT / Auxiliary Fuel Tank CWT location of penetration fittings –NEA –Thermocouples –Oxygen / FAS Sample Return Fitting –Hi Level Float Valves –Auxiliary Fuel Tank Transfer / Vent Flange –Oxygen / FAS Sample Fittings (6)

18 Instrumentation – cont. 737 CWT

19 Instrumentation – cont. Auxiliary Fuel Tank

20 Future Work Facility will be a key tool for continued fuel tank inerting and flammability research –Study the affect varying surface temperatures have on flammability –Potential industry tool to validate new inerting systems and methodologies –Use facility to validate a variety of models for studying fuel tank inerting and flammability

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