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FAA Inerting System Flight Testing on an Airbus A320. William Cavage AAR-440 Fire Safety Research Federal Aviation Administration. Systems Fire Protection Working Group DTA - Grenoble, France June 21-22, 2003. Outline. Goals and Objectives OBIGGs Instrumentation System Center Wing Tank - PowerPoint PPT Presentation
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Systems Fire Protection Working Group
DTA - Grenoble, France June 21-22, 2003
FAA Inerting System Flight Testing on an Airbus A320
William CavageAAR-440 Fire Safety Research
Federal Aviation Administration
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
Outline• Goals and Objectives
• OBIGGs
• Instrumentation– System
– Center Wing Tank
– OBOAS
– Additional Parameters
• Analysis
• Data– System Performance
– Fuel Tank Inerting
• Summary
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
FAA OBIGGs Installation Drawing
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
FAA OBIGGs Installation Drawing
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
FAA OBIGGS Installation
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
Flow Meter
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
CWT Instrumentation
NEA DepositVent Location
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
OBOAS Mounted in A320 Test Aircraft
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
No.Airbus
Designator Date Description1 1969 8/18/04 Started with CTR TK not inerted (20% O2) and empty. 2 ASMs,
OBIGGS started 10 mins before take off. Low flow climb and cruise(39,000ft), high flow in descent (normal descent).
2 1970 8/19/04 Started with CTR TK inerted (9% O2) and empty. 2 ASMs, OBIGGSstarted 10 mins before take off. Low flow climb and cruise (39,000ft),high flow in descent (rapid descent).
3 1972 8/20/04 Started with CTR TK not inerted (20% O2) and empty. 1 ASM, OBIGGSstarted 10 mins before take off. Low flow climb and cruise (39,000ft),high flow in descent (rapid descent at beginning).
4 1973 8/21/04 Started with CTR TK not inerted (19% O2) and with 1.5t (23%) fuel allflight. 1 ASMs, OBIGGS started 10 mins before take off. Low flow climband cruise (39,000ft), high flow in descent (normal descent).
5 1974 8/22/04 Started with CTR TK not inerted (20% O2) and with 3t fuel normalusage. 1 ASM, OBIGGS started 10 mins before take off. Low flowclimb and cruise (39,000ft), high flow in descent (normal descent).
6 1976 8/27/04 Started with CTR TK inerted (10% O2) and with 3t fuel (46%) normalusage. 1 ASM, OBIGGS started 10 mins before takeoff. Low flow forentire flight (rapid descent).
Table of Airbus Flight Tests
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
Data Analysis• Calculation of bleed air consumed
)][21.0(
)][]([
2
22
Perm
PermNEANEABleed O
OOQQ
• Model of Ullage gas Oxygen Concentration
21.*)*()1()*()1()1()(22 TankTankOO VtUGOFVtUGOFmIGOFmtmtm
= Mass of oxygen in tank at time t = Mass flow rate of inerting gas (in terms of t)
IGOF = Fraction of oxygen in inerting gasΔρ = Change in Ullage Density due to Altitude ChangeVTank = Volume of Tank UllagemTank = Mass of Gas in Tankmair = Mass of air entering tank
)(2tmO
m
With: = NEA Oxygen Concentration = OEA Oxygen Concentration
NEAO ][ 2
PermO ][ 2
TankO mtmtUGOF /)1()1(2
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
0
2
4
6
8
10
12
14
16
18
20
0 20 40 60 80 100 120
Time (min)
[O2
] (%
vo
l)
0
10
20
30
40
50
60
Alt
(kf
t)/P
res
sure
(p
si)/
Flo
w (
scfm
)
NEA Line O2 (%)
ASM Inlet Pressure (Psig)
NEA Flow (SCFM)
Alt (kft)
Single Membrane Test
Switch to HighFlow Mode
System Performance Data
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
0
2
4
6
8
10
12
14
16
18
20
0 5 10 15 20 25 30 35 40 45 50
Time (min)
Flo
w (
scfm
) / [
O2]
(%
vo
l)
0
10
20
30
40
50
60
Pre
ssu
re (
psi
g)
NEA Flow (SCFM) NEA Flow (SCFM)NEA Line O2 (%) NEA Line O2 (%)ASM Inlet Pressure (Psig) ASM Inlet Pressure (Psig)
2 Membranes1 Membrane
One vs. Two ASM Performance Data
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
Bleedair Consumption Data
0
10
20
30
40
50
60
0 20 40 60 80 100 120
Time (min)
Flo
w R
ate
(SC
FM
)
NEA Flow (SCFM)
Bleedair Flow (SCFM)
Permeate Flow (SCFM)
Single Membrane Data
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
CWT Inerting Oxygen Concentration Data
0
5
10
15
20
25
0 20 40 60 80 100 120
Time (min)
[O2]
(%
vo
l)
0
5
10
15
20
25
30
35
40
45
Alt
itu
de
(kft
)
O2 Sample 1 (%)O2 Sample 2 (%)O2 Sample 3 (%)O2 Sample 4 (%)O2 Sample 5 (%)O2 Sample 6 (%)O2 Sample 7 (%)O2 Sample 8 (%)Alt (kft)
Single Membrane Test
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
One vs. Two ASM Tank Inerting Data
0
5
10
15
20
25
0 20 40 60 80 100 120
Time (min)
Oxy
gen
Co
nce
ntr
atio
n (
% v
ol)
One Membrane
Two Membrane
Average Tank [O2]
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
High Flow Mode Benefit Tank Inerting Data
0
5
10
15
20
25
60 65 70 75 80 85 90 95 100 105
Time (min)
Oxy
gen
Co
nce
ntr
atio
n (
% v
ol)
High Flow Descent
Low Flow Descent
Average Tank [O2]Single Membrane
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
Effects of Fuel Tank Inerting Data
0
5
10
15
20
25
0 20 40 60 80 100 120
Time (min)
Oxy
gen
Co
nce
ntr
atio
n (
% v
ol)
Empty Tank
Consumed Fuel Load
Average Tank [O2]Single Membrane
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
System Performance Data
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
AAR-440 Fire Safety R&D
Airbus Inerting Flight Test___________________________________
• FAA simplified OBIGGS concept validated– 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
Summary