0. Flammability Reduction Methods: Compliance Options
Federal Aviation
Administration
Flammability Reduction Methods: Compliance
Options
AAR-440 Fire Safety Branch Wm. J. Hughes Technical Center Federal Aviation Administration

1. Reticulated Foam Advantages: 100% protection Passive System
No model – no need for flight testing
Disadvantages:
Weight
Fuel displacement
Interference with maintenance
Haz. Mat. When out of tank
Certification issues:
Foam pedigree
Voiding
Durability
Interference in tank

2. Inerting with Stored CO2
Advantages: ?
Disadvantages:
Must be stored on aircraft
Certification issues:
Needed O2 concentration not known
Fuel solubility
Effect on pumps

3. Inerting with Exhaust Gas
Advantages:
Already produced on aircraft
Disadvantages:
How to obtain
Certification issues:
Needed O2 concentration unknown
Contaminants unknown

4. Catalytic Inerting Advantages: Possible weight
Less power from aircraft
environmental
Disadvantages: ?
Certification issues:
Needed O2 concentration not known
Fuel solubility
Effect on pumps

5. Rapid Ventilation Advantages: Cost Weight Disadvantages: Loss of fuel
Environmental
Need for in-tank monitoring
Certification issues:
Tank flammability verification

6. Misting Fuel Vapor Advantages: Possible weight savings
Possible lower cost
Disadvantages:
Loss of fuel
Environmental
Safety issues
Certification issues:
Post crash implications
Failure modes
In-tank hydrocarbon measurements

7. Nitrogen Inerting
Cryogenic Nitrogen
High Pressure Stored Nitrogen
Ground Based Nitrogen
Two Flow Nitrogen
Full Time On Demand Nitrogen

8. Cryogenic Nitrogen Stored: Too heavy
Manufactured: Developing technology

9. High Pressure Stored Nitrogen
Too Heavy

10. Ground Based Nitrogen
Logistics
Manpower

11. Two Flow Nitrogen
Present system of Choice

12. Full Time On Demand Nitrogen
Advantages:
Less power from aircraft
Environmental
Disadvantages:
Weight
Vent valve