# Presentation: 725227

## FAA Inerting System Flight Testing on an Airbus A320

- William CavageAAR-440 Fire Safety ResearchFederal Aviation Administration

## Outline

- Goals and Objectives
- OBIGGs
- Instrumentation
- System
- Center Wing Tank
- OBOAS
- Additional Parameters
- Analysis
- Data
- System Performance
- Fuel Tank Inerting
- Summary

## Testing Goals and Objectives

- Validate the simplified inerting concept and develop/expand upon existing system performance models
- Examine system sizing requirements
- Validate in flight inert gas distribution assumptions
- Examine potential operational effects on the ability of a system to maintain inert conditions in a fuel tank

## OBIGGS - System Architecture

- Uses Air Separation Modules based on HFM technology
- Excepts hot air from aircraft bleed system
- Cools, filters, and conditions air
- Air is separated by ASMs and NEA is plumbed to output valves to control flow
- OEA is dumped overboard, H/X cooling air deposited in cargo bay near outflow valve
- System configured  to operate in high and low flow modes
- Prototype system controlled by control box in cabin that is connected to system with cable
- Install system in test aircraft cargo bay for simplicity sake

## FAA OBIGGs Installation Drawing

## FAA OBIGGs Installation Drawing

## FAA OBIGGS Installation

## Instrumentation and Data Acquisition

- Various thermocouples and pressure transducers used to evaluate system performance
- OBIGGS system flow meter and 2-channel oxygen analyzer for NEA and OEA analysis
- Eight sample locations within the Center-Wing Tank (CWT)
- FAA Onboard Oxygen Analysis System (OBOAS) utilized
- Aircraft parameters measured
- Airbus data acquisition system utilized
- Full-up flight worthy DAS

## System Instrumentation Diagram 

- Static Pressure

- Temperature

- Spare [O2]

- Static Pressure

- Temperature

- OEA [O2]

- Temperature

- Static Pressure

- Temperature

- Temperature (FAA Reader)

- Static Pressure

- Temperature

- NEA [O2]

- Penetration
- Hole

## Flow Meter 

## CWT Instrumentation

- NEA Deposit

- Vent Location

## OBOAS Mounted in A320 Test Aircraft 

## Test Plan

- Operated system in two flow mode for a series of tests with a 39,000 ft cruise altitude and a high rate of descent (4k ft/min)
- Descended to 3,000 feet for operational purposes
- Nine total tests, 6 relative to FAA testing goals and objectives
- Used OBIGGS in both a single ASM configuration and a 2-membrane configuration to evaluate sizing requirements
- Testing proved the FAA system concept, acquired system sizing data, and examined the effects of several operational conditions
- Studied effect of fuel on an inert ullage
- Studied effect of the high flow mode on the inert ullage
- Studied effect of bleed air on the membrane performance

## Table of Airbus Flight Tests 

- Table of Airbus Flight Tests

## Data Analysis

- Calculation of bleed air consumed

- Model of Ullage gas Oxygen Concentration

- 				=   Mass of oxygen in tank at time *t*
-   			    	=  Mass flow rate of inerting gas (in terms of *t*)			*IGOF*  	=   Fraction of oxygen in inerting gas
- 			Δρ	=  Change in Ullage Density due to Altitude Change
- 			VTank	=  Volume of Tank Ullage
- 			*m**Tank*   	=  Mass of Gas in Tank
- 			*m**air*   	=  Mass of air entering tank

- With:	       =  NEA Oxygen Concentration
-  	       =  OEA Oxygen Concentration

## Results -  System Performance

- System performed as expected with predictable ASM dynamic charactaristics
-  Easily predicted with static measurements
- 2-membrane system configuration gave approximately double the NEA
- Less at altitude probably due to OEA back pressure
- Bleed air consumption greater then expected
- Aircraft bleed air pressures were higher then expected at altitude
- ASM degraded during the ground and flight testing (~ 100 hours) giving about a 14% reduction in productivity
- Not much more then normal expected “break-in” of ASM

## System Performance Data 

- System Performance Data

## One vs. Two ASM Performance Data 

- One vs. Two ASM Performance Data

## Bleedair Consumption Data 

## Results -  Tank Inerting

- CWT inerting accomplished easily
- No stratification observed, ullage acted in a very homogenous manner
- Two ASM inerting gave very little benefit compared to a single ASM
- Different system “tuning” could change that
- High flow mode effective at helping maintain a low resulting ullage oxygen concentration during descent
- Fuel load had very little effect on measured ullage oxygen concentrations for both static and consumed fuel loads
- Simple model effective at predicting resulting ullage oxygen concentration given a system performance and mission profile

## CWT Inerting Oxygen Concentration Data 

## One vs. Two ASM Tank Inerting Data 

## High Flow Mode Benefit Tank Inerting Data 

## Effects of Fuel Tank Inerting Data 

## System Performance Data 

## Summary

- System performance predictable
- Bleed air consumption significant
- ASM performance degradation needs to be studied further
- Fuel tank inerting
- Inert gas distribution accomplished easily
- System tuning needs to be studied further to say true benefit of 2 ASMs versus 1
- Two flow mode beneficial
- Fuel load effected resulting ullage oxygen concentration very little
- Ullage inerting easily modeled given a system performance