Blue Avionics has developed an ILS deviation system with an offset application using its BA-540 Adaptable Avionics Unit (AAU) and obtained certification for installation in a Cessna Citation 560XL. The ILS deviation system is used for pilot training, where the instructor can induce a deviation in the localizer or glideslope display during instrument approach training. Duncan Aviation’s Lincoln, Nebraska headquarters facility did the systems integration and certification of the 560XL application.
Unlike dedicated avionics boxes, the BA-540 AAU allows integrators and installers to design new avionics functions and use the AAU to implement these functions. In addition to the BA-540 AAU, Blue Avionics offers the BA-440 Router/Filter and BA-110 Arinc to CDSB Unit, which further expand the number of functions that can be implemented.
Blue Avionics systems have been installed on a variety of aircraft, according to Ross Cairns, company founder and v-p of engineering. “The same BA-540 AAU with no software or hardware changes is being used for many other certified functions, everything from performing as an airspeed/Mach warning computer to ADS-B Out DO-260B compliance monitoring.”
For the 560XL, the BA-540 provides the instructor with a momentary annunciation switch that can be used to select the direction of deviation (up, down, right, or left). Each switch illuminates to indicate the instructor’s selection. During training, if the instructor selects another mode or if the pilot selects go-around mode, the deviation training system reverts to normal ILS mode. The 560XL installation includes a second BA-540 to interface the Collins GLU-920 multi-mode receiver (MMR) with the L3 EHSI-4000 standby instrument, so the ILS indications on the standby match those on the flight deck displays.
“The adaptable BA-540 AAU is configurable to perform hundreds of functions on aircraft,” said Cairns. “On the Citation 560XLs, the BA-540 AAU is handling 85 functions and logic equations in the ILS offset system and 33 different functions and logic equations in the MMR-to-EHSI interface.” The AAU can provide the deviation for both ILS and pseudo-ILS indications.
According to Cairns, it would be easy to configure the ILS Deviation system to allow offset for both the glideslope and localizer indications at the same time, but for the 560XL application, the customer wanted only one indication at a time for its pilot training needs. The size of the deviation could also be set to meet customer requirements, to less than a dot or several deviation magnitudes. The system works with federated ILS avionics or with integrated avionics and flight management systems. It could also be installed in flight simulators.
The concept of being able to input a deviation is not new and has been done before with a special test rig, Cairns said. “We are able to do it with our off-the-shelf products. The idea is the same as missing instruments or blocked instrument training. It’s just another method to test new pilots to adverse conditions or instruments that are not correct.”