Systems Fire Protection Working Group Taj Mahal - Atlantic City, NJ November 4, 2003 FAA Concept OBIGG System Flight Testing on NASA 747 SCA William Cavage

Systems Fire Protection Working Group

Taj Mahal - Atlantic City, NJ November 4, 2003

FAA Concept OBIGG System Flight Testing on NASA 747 SCA

William CavageAAR-440 Fire Safety Research

Federal Aviation Administration

AAR-440 Fire Safety R&D

FAA-NASA 747 Inerting Flight Test___________________________________

Outline• Goals and Objectives

• OBIGGs Architecture

• OBIGGs Installation– Pallet

– NEA Deposit

• Instrumentation / DAS– CWT

– System

– OBOAS / FAS

– Data Acquisition

– Power Distribution

• Status



Testing Goals and Objectives• Prove the simplified inerting concept and validate/expand

upon existing system performance models

• Develop/validate system sizing data

• Validate previous in flight inert gas distribution modeling done by FAA

• Measure the progression of flammability in the CWT of a typical commercial transport airplane



OBIGGS - System Architecture• 400 deg F bleed air enters electrically controlled &

operated Shut-off Valve on OBIGGS Control Box

• Air goes through heat exchanger by a cooling air throttling valve to control temperature manually using a ASM air input temperature sensor– Some bleed air can bypass the heat exchanger if selected

• Conditioned air passes through dust/oil contaminant filter

• Air enters ASM and has OEA separated and dumped overboard



OBIGGS - System Architecture (cont’d)• NEA passes through high flow shut-off valve (Parker Box

operator) and High/Low flow metering valves

• System controlled by control box in cabin that is connected to system with cable routed through wheel well– Turns system on/off

– Select heat exchanger bypass on/off

– Select fan on/off

– Select high/low flow mode

– ASM input air temperature readout



Assembled FAA OBIGGs Drawing



OBIGGS - System Installation• System installed in aft, right side fairing area (empty pack bay)

• System is mostly assembled before installation in the aircraft– Total Weight = 165 lbs

• System attaches to fairing structure at six locations with specially design mounting brackets– Brackets designed by Shaw for canceled FAA joint flight test with Boeing

– 4 main brackets pick up existing fastener holes but two secondary brackets need to have holes drilled in stringer

• System wired to control box in cabin via a cable which attaches to the system 41-pin connector– Powers/controls system components



OBIGGS - System Installation (cont’d)• System interfaces with bleed system via a main bleed duct

manifold in that area– 4-foot segment from SCA is removed and FAA segment installed

– Needs to align precisely with system bleed air input fitting

• System cooling air passes in a scoop and out the outflow box– Two FAA panels with these parts already mated with aircraft



Top View of System Installed

Inboard AircraftStructure

Outboard AircraftStructure



Simplified OBIGG System Installation



Empty Pack Bay Before/After System Installation



OBIGGS - Deposit System• Install deposit “T” and dual isolation valves allows for

improved functionality of testing (counter-wire valves)– Install a “T” in system NEA deposit

– 1 side of “T” goes to outflow box via a normally closed isolation valve

– Other side of “T” goes to flow meter, check valve, and a second normally open isolation valve

• Install AN bulkhead fitting in replaced pack bay canted bulkhead panel– Route NEA from check valve to fitting with flexible hose



Deposit System Overview



NEA Deposit “T”



Flow Meter/Deposit Installation



NEA Diversion Valve Installation



• To deposit NEA in tank without permanent modification replaced purge door with “instrumentation panel” that passes the NEA, thermocouples, and gas samples (not FAS) into the tank from the wheel well adjacent to the pack bay– NEA fitting is 1” SwageLok Bulkhead Fitting

• NEA routed to deposit nozzle mounted in the top of tank in Bay 6 (aft, right bay) via a 1-inch flexible line– nozzle mounted in bracket attached to aircraft stiffener bracket

between strings at top of tank

• Also Blocked Half Vent System

OBIGGS - Deposit System (cont’d)


FAA-NASA 747 Inerting Flight Test___________________________________Install Instrumentation Port



Existing Stringer/Stiffener/Bracket Assembly



Install NEA Deposit Nozzle and Associate Hardware



Install Vent Blocking Plates



Instrumentation and Data Acquisition• Various thermocouples and pressure transducers used

– Evaluate system performance

– Measure tank flammability parameters

• OBIGGS system flow meter and 2-channel oxygen analyzer for NEA and OEA analysis

• Onboard Oxygen Analysis System (OBOAS) most critical measurements– 8-channel system analyzes 8 locations in tank

• Flammability Analysis System (FAS) will measure progression of CWT flammability in flight– 1 location in forward section of tank



CWT Instrumentation• Installation Instrumentation in the CWT of the NASA

SCA– Install Instrumentation Panel in Place of Purge Door

– Route and Mount Thermocouples

– Install Sample Port Float Valve Assembly and Route Lines as well as sample return lines

• Sub-Contractor (FFC) supported FAA installation– Highly experienced in this type of work

– Statement of Work gives more details



Route and Mount Thermocouples Front Spar

Spanwise Beam #3

Spanwise Beam #2

Midspar

Spanwise Beam #1

Rear Spar

237"

57"

42"

55"

42"

255"

26.5"

(STA 1000)

(STA 1241)

To LeftSurge Tank

To RightSurge Tank

Vent Channels

41"

1 2

3 4

5 6

7 8

Dry Bay

Bay 1

Bay 2

Bay 3 Bay 4

Bay 5 Bay 6

9 10

11 12

13 14

15 16

17

19

20

18

21

22

24

23

nn Ullage Fuel n Floor, Wall, & Ceiling Mounted



Install Sample Port Float Valve Assembly



Instrumentation - Additional Thermocouples• Use 16th Inch SS Sheath T-Type Thermocouple

Probes

• Install one in each used pack bay and one in the OBIGGS pack bay

• Install 4 in the area of the bleed air connection– Monitor for Bleed Air Leaks

• System has 6 thermocouples installed

• Thermocouple in cabin

• Thermocouples in measurement systems (OBOAS/FAS)



• Measure Absolute Pressure at 4 locations on OBIGGS and measure static pressure in pack bay– Potential to add 1 to bleed manifold if possible

• Purchase off-the-shelf lab pressure transducers– Sensotec TJE Precision, Absolute series

– Run on 28 VDC, 12 VDC nominal bridge voltage, internally regulated

– 0-5 VDC output

• Mount transducers on panel in cabin– Run 5 sense lines to pack bay

Instrumentation - Pressure Transducers



Thermocouple Probe and Pressure Transducer



Instrumentation - NEA Flow Meter• Engineered Specifically for The FAA OBIGGS

– Designed from Existing Commercial and Military Assemblies by FCI

– Flight worthy instrumentation (No TSO)

– Uses vortex shedding heat release principal

– Also measures absolute temperature and pressure of flow

• 1” diameter flow tube integrates with existing deposit system on pallet



Flow Meter



System Instrumentation Diagram

Static Pressure Temperature

Spare [O2]


OEA [O2]

Temperature

Static Pressure

Temperature Temperature (FAA Reader)


NEA [O2]

Penetration Hole



Instrumentation - OBOAS• Two 4-Channel Systems Measure Oxygen Concentration

Continuous at 8 Different Fuel Tank Locations– Large diaphragm pump draws sample

– Actively controls sample inlet and outlet pressure.

– Flow through sensor design

– Fluid traps, Ejector/Evacuator, Flame Suppressors for Safety

• Mounts in standard 19” flight test half rack including sample system (OBUSS) contained in large, purged box



OBOAS Block Diagram

Fuel Tank VaporFuel Tank LiquidPressurized AirElectrical PowerElectronic Signals



OBOAS Mounted in FAA AMCO Racks



Instrumentation - FAS• System uses a Non-Dispersive Infrared Analyzer

(NDIR) to measure fuel tank flammability in the form of total hydrocarbons (THC)

• Sample stream must be heated at all points leading to the NDIR to prevent condensation of fuel vapors– This is achieved in part via three heated hoses

• Installs in a rack and pallet for flight test



Aircraft Cabin

FAS

Air

OBOAS

Exi

stin

gPo

wer

Rac

k

Window Plug

DASOBIGGS

Air

Air

Air

OBOAS

Compressed Air Bank (Cargo Bay)

Penetration STA 1275

Penetration STA 1248

Penetration STA 980

Power Cable

System Wiring

Sample Tubing

Purge Air Line

Instrumentation Wiring

To Avionics Bay

STA 990 STA 1010 STA 1080 STA 1120 STA 1250

FASAnalyzer

Sample System

Cabin Instrumentation/Rack Diagram



• Power Distributed to the Various Equipment from Utility Rack at ST. 990 – 3-Phase 115 VAC 400Hz to Each OBOAS (13 amps/leg)

– 20 Amps of 115 VAC 60 Hz to FAS

– 5 Amps of 115 VAC 60 Hz to DAS and Computer

– OBIGGS takes 5 Amps 28 VDC and 3-Phase 115 VAC, 400Hz (5 Amps/ Leg)

• Each OBOAS converter is tied to a switching unit that allows for power to be distributed between racks and to the OBIGGS O2 analyzer

Instrumentation - Power Distribution



Power Distribution Diagram OBIGGS

Analysis Pump

OBOASPump 1

OBOASPump 2

OBOAS Rack Assembly

OBIGGSControl

Box

DAS

Computer

DAS &OBIGGSRack

NDIRAnalyzer

SampleSystem

FASRack

Power StripPower Strip

115 VAC, 400 Hz Bus

Existing60 Hz Power

Converter

28 VDC Bus

Existing Power Rack

OBIGGS AnsySample Train



• IOtech Ethernet Based Daqbook– 16-bit 200 kHz A/D Converter

– Daisy chains slave units with 3-boards each

– Expandable up to 256 channels

• Specified approximately 78 channels of data – CWT / OBOAS/ FAS - 48 channels

– System Instrumentation - 15 channels

– Misc. Temperatures - 9 channels

– Aircraft Parameters - 2 channels

Data Acquisition System



Data Acquisition System

Data

Data

Daqbook / 2000E

DBK60 Expansion



• CWT installation approved and completed

• OBIGGs, OBOAS, FAS, instrumentation/racks, & DAS installation approved– One sticking point

• OBOAS modified from Airbus testing and FAS completed

• Additional parts purchased

• NEA deposit completed,

• Instrumentation racks built up

• Preparing to ship all equipment for installation

Status

Documents

Systems Fire Protection Working Group Taj Mahal - Atlantic City, NJ November 4, 2003 FAA Concept OBIGG System Flight Testing on NASA 747 SCA William Cavage