OBIGGS Sizing Data for Transport Canada Trade Study William Cavage AAR-440 Fire Safety Branch Wm. J. Hughes Technical Center Federal Aviation Administration International Systems Fire Protection Working Group Place de Ville Tower C Ottawa, Canada February 14-15, 2005

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Outline Background Methods Baseline Data Results Summary

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Objective of Work Develop data on OBIGGS system performance to be used for a fire fighting trade study –Must quantify the size of system needed in terms of the number of ASMs for several different size aircraft o Must quantify fuel tank size and descent time at a minimum –Base calculations on flight test data Use OBIGGS size data to develop fire fighting capability of the system

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Develop System Sizing Data Create 3 aircraft CWT sizes based on familiar aircraft –Small (A320), Medium (747SP), and Large ( ) Develop a spec missions (2) based on modified A320 flight test profiles Do analysis to size systems –Base system performance on measured flight test data Use purity and flow measured on single ASM A320 flight test Assume each CWT is a single bay box with a single deposit and vent –Make calculations of resulting ullage oxygen concentration using developed FAA ullage inerting model Determine number of ASMs needed to land below 12% for 2 different system methodologies (dual flow & single high flow)

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Specified Low Descent Rate Mission

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Example of Ullage Model Results of System Sizing

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Example of Ullage Model Results of System Sizing

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Results of Analysis – Low Descent Rate

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D Results of Analysis – High Descent Rate

Canada TSB Trade Study Inerting Data ____________________________________ AAR-440 Fire Safety R&D FAA used developed tools to size systems for generic aircraft for trade study of OBIGGS fire fighting capability Developed a range of flows and maximum flows predicted for use in aircraft fire fighting given three generic single bay fuel tanks –More work is needed to characterize specific volume flow and purities expected from each system give specific altitudes and bleed air pressures outside of observed flight test conditions More work needed to quantify the effects of a compartmentalized tank on system sizing requirements Summary