The head-up display or HUD is all but standard equipment in airliners and business jets, but it has proven a resilient non-starter in light aircraft general aviation. We would guess this is because pilots don’t see a burning need for HUDs and, thus far, none have worked very well.
MGF-MyGoFlight Products-hopes to reset that clock with its SkyDisplay HUD aimed dead center at the light aircraft and small turbine market. It’s intended as an affordable option, but at $25,000 installed, some might argue the point.
We recently flew the SkyDisplay in a Cirrus SR22 with MGF owner Charlie Schneider and conclude if any light plane drivers really want a HUD and if MGF gets past the certification hurdles, the SkyDisplay is a functional if not perfect device.
Anyone who has attended the big aviation shows will know MGF as a purveyor of flight bags, GPS and camera mounts and other such gadgets. Because the company designs and builds at least some of its own products, it has developed a cottage industry industrial base that Schneider told us he applied to creating the SkyDisplay.
HUDs are simple in concept, but not so simple to engineer and install. They’re basically an optical projector that displays an informationally compressed flight data display on a glass screen called a combiner. The idea is that the pilot can look through the display and see critical data such as attitude and airspeed while avoiding the distraction of looking down at the panel. The display has to be engineered in such a way that the data appears almost at infinity, so as to be an aid, not a distraction.
MGF’s iteration of this technology uses commercial off-the-shelf hardware from the automotive industry for the projector and a purpose-built, cabin ceiling-mounted bracket to tie the projector and combiner together. MGF sources the components offshore, makes some of its own parts and assembles the HUD at its Denver headquarters.
Schneider told us each aircraft will require a dedicated bracket and the company plans to provide these for popular models, although the full model list isn’t fleshed out yet. He says the first approvals are expected this summer. The HUD is attached through posts bonded to the cabin ceiling via a mounting bracket.
In the legacy SR22 we flew, the airplane’s Avidyne Entegra and Garmin 430s provided the data, which is crunched by a computer that’s mounted behind the panel. The SkyDisplay uses ARINC 429 data from the navigators and serial data between the PFD and the autopilot so it can tell what the flight director is commanding. The refresh rate, says Schneider, is 16 MHz, so there’s no noticeable latency in the display.
Schneider says he doesn’t know if all avionics manufacturers will allow access to their high-speed bus data, but he believes SkyDisplay will function adequately with slower data MGF can access from newer navigators, such as Garmin’s GTN series and the just-announced GPS 175.
In flying it, we adapted quickly, although it takes discipline to actually use the data effectively. On a couple of approaches, keeping the flight director cue inside-or at least near-the flight path marker kept the airplane on rails to DA or MDA. Once the runway looms up through the clag, you can flip the combiner up and complete the landing visually. Or use it as a reference all the way to the runway. Call us old school, but we would do the former. Using it for landing and takeoff, while possibly of some benefit, tends to encourage obsessing over data at the expense of having a feel for the airplane, which we think is something desirable in a light piston aircraft. Heavier and faster aircraft are different and more likely to benefit from disciplined use of a HUD.
That said, MGF might find some traction among owners who fly serious IFR, especially at night, and from pilots who just like gadgets. The device performs as claimed, but we doubt if it will rise to the must-have equipment category.
Photographing a HUD in action is harder than finding black holes and Leprechauns. The above image is a computer-generated frame from our trial flight in the SR22. It depicts industry-standard symbology that allows the use of only two colors, green and magenta. In flight, the above imagery is superimposed on what the pilot sees through the windshield.
The basic functionality is similar to the pilot’s primary flight display, but with information compressed into a smaller image. Central to the HUD’s appeal are the flight path marker and the flight director cue. The flight path marker depicts where the aircraft flight vector is headed, while the flight director cue indicates what the autopilot is commanding, whether it’s flying the airplane or not.
The pitch ladder is a direct indication of pitch up or down and the zero pitch line indicates level flight. Heading is shown in three formats: the HSI at the bottom of the page and in digital repeaters above the HSI and under the bank angle indication.
