Once only available for experimental aircraft, Garmin earned an FAA STC for its GHA 15 radar-based height advisor system. It’s the first certified radar altimetry system available for GA aircraft in a number of years, and the AML-STC covers more than 500 class I and II aircraft. The current interface is on Garmin’s GI 275 electronic flight instrument where, starting at 500 feet for landing, it provides visual and voice alerts.
The GHA 15 is a two-piece system, including the GI 275 display and the self-contained GHA 15 module that weighs less than one pound and mounts to the bottom of the fuselage. The system is pilot-configurable for altitude callouts at specific heights above the ground (starting at 300 feet) and accurate to call the altitude to 1 foot above the ground or water. “Fifty, Forty, Thirty,” and so on.
Garmin said the GHA processes hundreds of altitude measurements per second and applies digital filters to maintain an accurate real-time reading of the aircraft’s AGL altitude. The voice callouts require connection to a compatible audio panel, which is pretty much any that accommodate an aux input.
The GHA 15 for certified aircraft has a list price of $2,695 and is available through Garmin dealerships now. The experimental version is $2,395 and works with the G3X Touch integrated avionics, in addition to the GI 275.
I’m pretty sure the Garmin unit is LIDAR. Once again experimentals lead the way – it was 4 years ago I installed a LIDAR-driven automatic gear extension, using years-old plans from Marc Zeitlin. Yes Zeitlin is way ahead, but why is Garmin trailing so much?
Negative. Garmin said the tech in its GHA 15 is not Light Detection and Ranging (LIDAR).
It uses Millimeter wave radar – the same technology that is used in adaptive cruise control (hence limited range of 500ft)
MicroKit Solutions also offers a LIDAR-based system. Except theirs is certified, just like Garmin. They’re just one of several. However, they all suffer the same problem of being unable to work over water. That’s the big advantage of the Garmin system. It can sense height above water that LIDAR systems currently cannot. This is not simply a seaplane/floatplane issue. There are many airports with approaches over water (KBDR and KHVN just to name two). The Garmin system could give a gear-warning callout at such locations long before short final.
LIDAR systems also sometimes “see” a stratus cloud layer as the ground and give out warnings. Additional logic must be added to prevent, say, automatically extending the gear while in cruise flight. Given that, I’d be curious to see if the Garmin system is immune to such false alarms.
I find it strange that Garmin chose to only allow interface with the GI 275 in the STC. The GHA 15 is already in use with the G3X Touch so the integration code is there. It feels like a marketing strategy for the GI 275. Is there a plan to add the G3X Touch, along with other PFDs, to the STC?
I assume it would be a good aid for landing on smooth surface water where distance above surface is harder to judge.