Swiss Supersonic Air Data Computer Selected for F-5 Avionics

AC32 supersonic air data computer, manufactured by Thommen Aircraft. Photo courtesy of Thommen Aircraft

A fleet of F-5 fighter jets used for simulating air to air combat missions for U.S. military pilots is adding a supersonic air data computer from Swiss avionics manufacturer Thommen Aircraft to an integrated flight deck upgrade first announced at the 2018 Farnborough International Air Show.

The F-5 fighter jets, operated by Nevada-based tactical aircraft training provider TacAir, will be upgraded with a G3000 integrated flight deck. Circle Air Group, which owns the F-5 fleet operated by TacAir, is performing the G3000 upgrade and announced the selection of Thommen’s AC32 Nov. 9.

“Thommen developed a special configuration to support legacy components, especially the temperature probes, still installed onboard of those older fighters. The AC32 is however seamlessly interoperable with the G3000 and any comparable integrated flight deck thanks to its highly configurable ARINC 429 data bus and its numerous discrete in and outputs,” a representative for Thommen told Avionics International.

TacAir operates the F-5s under commercial services and support contracts for several U.S. military domains, including the U.S. Air Force and Navy. Air Force and Navy pilots fly simulated air-to-air combat missions against the F-5s.

Under the G3000 upgrade, the F-5 fleet will new primary flight displays with synthetic vision and new touchscreen controllers with infrared vision. There are also a new mission computer and three-dimensional mapping navigation capabilities being added with the G3000 integrated flight deck. Garmin touchscreen controllers (GTCs) serve as the pilot interface to the flight display, and the touchscreen controllers incorporate infrared technology so pilots can use gloves in the cockpit.

The Garmin G3000 flight deck, pictured here, is being installed on a fleet of F-5 fighter jets owned by Circle Air Group and operated by TacAir. Photo, courtesy of Garmin International.

Thommen Aircraft CEO Stéphane Jaquier told Avionics International how the company added new software capable of calculating supersonic airspeeds based on critical pressure ratio. The upgrade includes a supersonic calculation formula capable of incorporating the Mach regimes and aerodynamic effects necessary for differentiating between subsonic (Ma < 1), transonic (Ma 0.8 < Ma < Ma 1.3) and supersonic (Ma > 1.0) speeds.

“When looking at the different options available on the market to upgrade the legacy air data system installed on our CF-5A and CF-5D fighters, we wanted a solution that could support high-performance operations, but that we could also implement with minimal costs and efforts,” said Dee L. Conger, Circle Air Group’s CEO.

Circle Air Group did not respond to an inquiry about when the installation of the AC32 air data computer would be completed. However, when the G3000 upgrade was announced, Garmin noted that the first flight of the F-5 equipped with the G3000 would occur in late 2018.

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