International Aircraft System Fire Protection

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FUEL TANK EXPLOSION PROTECTION SYSTEM - FTEPS
- based on an On Board Inert Gas Generating
System (OBIGGS)
A low impact retrofit system for fuel tank
inerting
Mr. G. Iazzetta - Fuel System Dept. Mr. E. Riegel
- Environmental Ctr. System Dept.
G 222

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G 222 Aircraft
The G 222 Aircraft is a STOL, twin turboprop
military aircraft for tactical transportation of
cargo, and troops over short and medium
ranges. The A/C has a MTOW of about 27.000 Kg
and it has 4 fuel tanks, 2 main and 2 auxiliary,
with a total volume of about 13.000 liters. The G
222 fuel tanks are vented by external air through
a couple of NACA scoop.
G 222

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G 222 A/C on semiprepared runway
G 222

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CUSTOMER REQUIREMENT (IAF)
Italian Air Force (IAF) requested ...to
protect fuel tanks against risks of fire and
explosion caused by projectiles, sparking, etc.,
and to assure protection from the threat of small
fire from ground during operation in hostile
regions.
G 222

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FTEPS/OBIGGS TECHNICAL CONCEPT
Basing on USAF studies, ullage oxygen
concentration less then 9 avoids the risk of
fuel vapor burn (fuel type JP-4, JP-5, JP-8),
consequently obtaining the protection of fuel
tanks from explosions caused by projectiles 50
cal. API-M8 or 20 mm HEI-M97. This value has been
obtained by USAF testing commercial kerosene and
JP-4, the latter considered worst case because of
its high vapor pressure and flammability,
covering all aeronautic used fuels.
SEE WADC TECHNICAL REPORT 55-418 - INERTING
CONDITIONS FOR AIRCRAFT FUEL TANKS
G 222

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FUNCTIONAL DESCRIPTION
FUNCTION AND PERFORMANCES
The FUEL TANK EXPLOSION PROTECTION SYSTEM,
realized with an OBIGGS, is a system that
protects the fuel tanks from explosions caused by
incendiary or explosive projectiles, sparks,
fire, with a continuous washing of fuel tanks
ullage with inert gas NEA (Nitrogen Enriched Air).
G 222

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FUNCTIONAL DESCRIPTION
FUNCTIONS AND PERFORMANCES

• The OBIGGS, main component of Fuel Tank Explosion
  Protection System (FTEPS), is an equipment that
  produces NEA with an oxygen content down to 1
  when fed in design conditions
• Feed air temperature 60 8 C (140 14 F)
• Feed air pressure More than 20 Psig
• The machine is provided of two Air Separation
  Modules (ASM), realized with Hollow Fiber
  Membranes that separate nitrogen from air.

G 222

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FUNCTIONAL DESCRIPTION
OBIGGS SCHEMATIC
NITROGEN ENRICHED AIR OUTLET
AIR INLET
OXYGEN ENRICHED AIR OUTLET
G 222

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FUNCTIONAL DESCRIPTION
FUNCTIONS AND PERFORMANCES

• FTEPS main characteristics are
• Non intrusive system
• holding of useful volume of fuel tanks
• Little weight increase (less than 100 kg)
• No operations of logistic support on-ground
• Previous operative experience on aircraft
  (L-159, Eurotiger)

G 222

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FUNCTIONAL DESCRIPTION
FTEPS SCHEMATIC
From ECS pack
Oxygen Enriched Air Outboard Discharge
G 222

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FUNCTIONAL DESCRIPTION
COMPONENTS
1 OBIGGS control panel 1 OBIGGS 1 NEA line
check-valve 6 calibrated orifices for NEA
distribution in fuel tanks 6 check-valves for NEA
distribution in fuel tanks 4 venting climb
valves 4 venting dive valves
G 222

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FUNCTIONAL DESCRIPTION
FTEPS/OBIGGS CONTROL PANEL
G 222

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FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERFACES
G 222

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FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERFACES
BATCS ARCHITECTURE
G 222

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FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERFACES
BATCS COMPONENTS
1 Fluid Pressure, Servo Air, Regulating Valve 1
Pneumatic Temperature Sensor 1 Low Temperature
Trim Valve 1 Check Valve 1 Automatic Drain
Valve 1 Heater Cuff for Automatic Drain
G 222

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BATCS BENEFITS

• No additional heat exchanger
• No dedicated cooling fan
• No ram air and exhaust for external air
• Completely automatic system

G 222

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FUNCTIONAL DESCRIPTION
OPERATIONAL MODES

• FTEPS working in Normal conditions allows to
  have
• NEA at 1 of O2 if the inlet pressure is more
  than 20 psig
• NEA at 5 of O2 if the inlet pressure is less
  than 20 psig.
• Operation in Descent condition allows
• To have NEA at 7 O2 even if inlet pressures are
  less than 20 psig

G 222

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G 222

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OBIGGS FTEPS PIPING LOCATION ON G-222 A/C
G 222

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OBIGGS
G 222

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G 222
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G 222
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G 222
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G 222
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INERTIZING FUEL TANKS ON GROUND APU ON -
DESCENT MODE ON
G 222
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