Tragedies such as the crash of TWA Flight 800 in 1996 have led to an emphasis on reducing the possibility of in-flight fuel tank explosions. The Federal Aviation Administration (FAA) William J. Hughes Technical Center at New Jersey''s Atlantic City International Airport, an aviation research and development/test and evaluation facility that serves as the national scientific test base for the FAA, has performed laboratory tests to seek ways of providing safer jet fuel solutions, but has only recently been able to obtain real-time in-flight data. Lab-based instruments used by the FAA are based on flame ionization detection (FID) techniques, which are unsuitable for in-flight use.
To get around this problem, the FAA recently obtained from Emerson Process Management a special Rosemount Analytical MLT 2 Multi-Component Gas Analyzer with two nondispersive infrared (NDIR) benches in parallel. The rugged design of the MLT 2 enables the analyzer to withstand the rigors of a flight environment -- such as vibration, pressure, and temperature changes -- to provide accurate, real-time in-flight flammability (hydrocarbon) data from the aircraft fuel tanks of NASA''s 747 SCA.
Rosemount Analytical''s MLT series of NGA 2000 analyzers offer multicomponent, multimethod analysis using infrared, ultraviolet, thermal conductivity, paramagnetic, and electrochemical oxygen sensor technologies. The MLT 2 gas analyzers measure up to five gas components, depending on configuration, in a single- or dual-compartment wall-mount enclosure. It can be configured as a standalone unit, as a "system control analyzer" with front panel display and keypad, or as an analyzer module (AM).
To meet the FAA''s needs, Rosemount modified the MLT 2 analyzer to control the temperature of the sample compartment up to 120°C, ensuring temperatures high enough to eliminate the chance of jet fuel condensation. Because of the success of the analyzer in high temperatures, the 120°C function is now a standard feature of the MLT 2. The analyzer is also capable of being continuously purged for safety purposes.
The analyzer succeeded in giving FAA researchers consistent readings when compared to typical FID detectors. It measured hydrocarbons as 2% propane equivalent with an accuracy at ±0.02% from sea level to 40,000 ft. Several predictive models had been established prior to the tests with varying temperature and altitude (pressure) conditions. After the completion of the tests, the actual in-flight hydrocarbon measurements served as a valuable tool for determining how well the models worked under these varying conditions.
The FAA placed its initial order for the MLT 2 HT in March 2003. Due to the success of the analyzer in in-flight jet fuel monitoring, the FAA recently ordered an additional unit.