1. Fuel Tank Inerting Joint Airbus/FAA, A320 Flight Tests
Presented by
Dr. Ali Tehrani
Systems Fire Protection Group Meeting
Atlantic City, New Jersey
Nov. 2003
Fuel Tank Inerting Joint Airbus/FAA, A320 Flight Tests
SCS/SYS/N/17/3737_01.DOC

2. Aims and Objectives The main objectives of the flight test are to:
Demonstrate supply of inert gas to the centre tank, throughout the flight profile, using the FAA prototype system,
Assess the centre tank gas distribution over different flight phases,
Validate the in-tank gas distribution (O2 concentration) measured with those numerically modelled,
Assess performance of a typical ASM operating during different flight phases.
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3. Test Installation
The source of Nitrogen Enriched Air (NEA) was obtained using equipment loaned from the FAA,
Equipment was located in the cargo bay on an LD3 pallet.
Bleed air provided by tapping into bleed air duct,
NEA was introduced into the centre tank using a pipe normally used for ACT fuel transfer when ACT is fitted,
The outlet housing configuration of the transfer pipe in the centre tank was used to incorporate a NEA discharge nozzle,
Oxygen concentration in the centre tank was measured using the FAA sampling system OBUSS,
This allowed measurement of oxygen concentration from 8 locations in the tank,
Additional measurements of temperature and pressure were made in the centre tank and on the NEA generating equipment,
Cooling air was supplied from the cargo bay environment,
OEA (Oxygen Enriched Air) was discharged over board using existing drain mast.
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4. Outline of OBIGGS Equipment and Interfaces
Isolation Valve
Cooling Air
Bleed Interface
NEA Supply Interface
Check Valves
Cooling Inlet Interface
NEA Injection Line
Shut Off Valve
Centre Tank
Heat Exchanger
NEA Flow
Temp control valve,
cabin controlled
Fan
Filter
ASMs
Heater
High and Low Flow Valves
(In common valve)
Bleed Line
Bypass Valve
with pressure supply bottle
Bleed Air Isolation,
controlled via cockpit
FAA PALLET
Cooling outlet Interface
Waste Flow Interface
Discharge Line
Outflow Valve
Outside Aircraft
Waste Flow (O2 rich)
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5. OBIGGS as installed on Pallet
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6. Centre Tank Oxygen Sensor Location
Probe 1
Probe 2
Probe 3
Probe 4
Probe 5
Probe 6
Probe 8
Probe 7
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7. O2 Measurement Locations in Centre Tank
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8. SCS/SYS/N/17/3737_01.DOC
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9. SCS/SYS/N/17/3737_01.DOC
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10. Ground and Flight Testing
Ground testing of the system included a period of 50 hours “mini-endurance” tests to gain confidence in the system operation.
The flight testing phase included a number of 9 flights, exploring system performance over a range of;
Tank fuel quantities
Climb and descent rates
Different OBIGGS operational configuration
Total flight test time was approximately 20 hours.
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11. Flight Test Data – Oxygen Concentration
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12. CFD results and Data Points, Ground Operation, Adjacent to Vent Inlet
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13. CFD Results and Data points, Ground operation, Tank Average
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14. Comparisons of Modelling and Data points – Tank Average
Measured Data
Oxygen Concentration
Predicted results
Time (Min.)
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15. Simulation of Ground Test (CFD)
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16. Conclusion
No major abnormal system operation was observed during different phases of the ground and flight test,
Variation in supply pressure appeared to have a dominating effect on the overall system performance,
Reasonably uniform O2 concentration observed within the tank during the climb and cruise,
Good agreement with numerical prediction of the gas distributions for steady states and flight phases.
Normal servicing of the aircraft was not hindered, but the maintenance crew were briefed on the operations associated with the potential hazards of nitrogen rich atmosphere.
Time taken to return tank to all air environment was approx. 30 Mins.
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17. Lessons Learnt
Thermal characteristic of the ASM needs further investigation.
Impact on reaching the optimum operating temperature
Operated in a conditioned cargo hold only investigated.
A variable flow system may offer some advantages,
Initial purging of the tank may impose additional ASM requirements post maintenance,
Function of the filter needs further investigation.
The filter used was oversized for this application.
The FRS concept proposed by the FAA was demonstrated to operate during the limited flight trials.
However,
significant development is still required for a fully commercial operational system.
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18. This document and all information contained herein is the sole property of AIRBUS UK LTD. No intellectual property rights are granted by the delivery of this document or the disclosure of its content. This document shall not be reproduced or disclosed to a third party without the express written consent of AIRBUS UK LTD. This document and its content shall not be used for any purpose other than that for which it is supplied.
The statements made herein do not constitute an offer. They are based on the mentioned assumptions and are expressed in good faith. Where the supporting grounds for these statements are not shown, AIRBUS UK LTD will be pleased to explain the basis thereof.
SCS/SYS/N/17/3737_01.DOC
Nov. 2003