An Acoustic Emission Test for Aircraft Halon 1301 Fire Extinguisher Bottles

Abstract : An acoustic emission test for aircraft Halon 1301 bottles has been developed, a prototype acoustic emission test system constructed, and over 200 used bottles tested at the repair facilities of the two manufacturers of these bottles. The system monitors a bottle with six acoustic sensors while the pressure of the bottle is raised by heating it in an oven. The sensors are held in position, with a fixed relationship between them, by a special fixture. This fixture is designed to fit spheres with diameters between 5 and 16 inches. Results of the tests on used bottles indicate that over 95 percent of the bottles showed no indication of significant defects. The rest had some indication of flaws or corrosion. However, all bottles tested to date have passed the hydrostatic test required by the U.S. Department of Transportation. Based upon this data, the Air Transport Association (ATA) requested an exemption from the DOT to allow their members to use this acoustic emission test in place of the hydrostatic test. This exemption, DOT - E 11850, was granted to the ATA on December 11, 1997.