NASA researchers have successfully tested a new generation of fire detectors that could significantly reduce the rate of false alarms in the cargo and baggage compartments of commercial airliners.<\/p>\n
The new sensor-based system was developed at NASA’s Glenn Research Center (GRC), Cleveland. It reads a more complete fire signature, and it is so sensitive it may reduce false alarm rates to zero.<\/p>\n
Most detectors sense smoke particles. They can be fooled by dust and other tiny airborne particles found in non-passenger aircraft compartments, which lead to false alarms. The team at GRC used MicroElectroMechanical Systems (MEMS) expertise to come up with a new multi-sensor approach.
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\n“We looked for increased concentrations of combustion gases along with the smoke,” said Gary Hunter, a Sensors and Electronics Branch aerospace engineer. “The multi-sensor package compares various gas concentrations and smoke particle sizes to those values characteristic of an actual fire. The result is a system that works to effectively recognize the presence of fire while screening out false alarms.”<\/p>\n
The MEMS sensor system includes miniaturized carbon monoxide and carbon dioxide sensors, a smoke particle detector and integrated software. These compact arrays can be placed in multiple locations throughout the aircraft’s cargo and baggage compartments. The on-board processor evaluates the response of the complete sensor system and indicates whether there is a fire.<\/p>\n
Fire alarms signal pilots to initiate emergency procedures. A Federal Aviation Administration (FAA) survey of airline maintenance reports has estimated that 100-200 false alarms occur for every actual fire. In-flight fires are rare, but there is no way for flight crews to verify sensor readings to know for sure a fire has started in a remote compartment. So every alarm must be taken seriously. This means using extinguishing equipment, declaring emergency priority over other air traffic and landing as soon as possible.<\/p>\n
GRC researchers teamed with colleagues from Case Western Reserve University, Cleveland; Ohio State University, Columbus; and Makel Engineering, Inc., Chico, Calif.; in collaboration with the FAA.<\/p>\n
Tests conducted at the FAA Cargo Compartment Fire Testing Facility in Atlantic City, N.J., successfully demonstrated the miniaturized, combined chemical and particle sensors approach. NASA’s multi-sensor package had a zero false alarm rate when exposed to conditions that would normally cause cargo compartment detectors to false alarm. Further testing alongside conventional smoke detectors in the FAA’s Boeing 707 under-floor cargo bay showed the system detected fire as well as conventional smoke detectors.<\/p>\n
Before the new system can be installed on airplanes, the sensors, software packaging and interface, long-term durability and drift effects need to be improved and certified by the FAA.
\nNASA’s Aviation Safety and Security Program sponsored the research as part of a joint NASA-FAA program. Industrial Research and Development Magazine recognized the effort as one of 100 best technical research and development achievements of the year.<\/p>\n
False alarms are also a concern in International Space Station operations and during space exploration missions, so NASA is sharing this research with spacecraft developers.<\/p>\n