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Applications Engineer
“These filters are compatible with most DC-DC converters ― a handy feature.”
Dave Berry
Phone:
   800-927-9474 (North America)
   00 800 8426 7000 (Europe)
   +852 2956-1782 (Asia)
Email: apps@vicr.com
Flight Management Systems (FMS)
Products Used
QPI Active Input Filters
Superior EMI / EMC Filtering for Flight Instrumentation
 

A flight management system (FMS) is a fundamental part of a modern aircraft.
It controls the navigation, holds the flight plan, and logs important data needed to ensure the scheduling of routine maintenance. It uses various sensors and global positioning equipment to determine the position, altitude and speed of the aircraft, and given the position and the flight plan, the FMS also helps guide the aircraft to the desired destination. The FMS is normally controlled through a small on-board computer which will output a display of the electronic flight instrument system. The modern FMS was introduced on the Boeing 767, though earlier navigation computers did exist. Now, they can be found on aircraft as small as the Cessna 172.

Flight management systems and other peripheral devices such as radar, terrain awareness, and data loggers, typically need to be able to operate from a noisy 24 Vdc voltage source that has been down-converted from the AC that is generated by the plane’s engines. A typical FMS device often has low steady state current requirements, at 7 A or less, but could have peak requirements up to 10 A or more. For these applications Picor’s QPI Active input filters can filter the EMI and support requirements up to 14 A.

In addition to aircraft EMI requirements, cockpit displays may require a low ripple power source, with noise levels <10 mV p-p. Power to displays is less than 30 V, and current levels can be as high as 10 A. Picor QPO and uRAM active ripple attenuators can support requirements up to 30 A.

Since cockpit space is tight and low-noise performance is critical, active filters provide unique value by combining superior noise attenuation and a compact package size. Both the QPI input filters and QPO output ripple attenuators come in a standard
25 mm x 25 mm x 12.5 mm low-profile LGA package.