On final approach to Runway 21 at Appleton International Airport in Appleton, Wisconsin, it’s difficult to grasp that no one is touching the controls.
Garmin’s Beechcraft King Air 200 flight test aircraft is flying itself down to touchdown amid the afternoon traffic during EAA AirVenture Oshkosh at nearby Wittman Regional Airport, with four of us on board.
Garmin announced this month that it expects certification of Garmin Autothrottle and Autoland for King Air 200s in the third quarter of 2023, with certification for 300-series airplanes in early 2024. The emergency system that can land autonomously in the event of an unresponsive pilot debuted with the Piper M600 and won the Collier Trophy for 2020. It has since been installed in the Daher 940/960 and Cirrus Vision Jet; this will be the first automated landing system certification as an aftermarket retrofit, as well as the first certification in a twin-engine aircraft.
Autoland and the associated autothrottle systems are the culmination of Garmin’s Autonomí suite of highly automated, integrated safety-enhancing technologies including Electronic Stability and Protection, Emergency Descent Mode, Smart Rudder Bias, and Smart Glide. The retrofit will be available for King Airs with G1000 NXi Phase II hardware and requires the installation of Garmin Autothrottle. More than 400 King Air 200s have G1000 or G1000 NXi.
Taxiing out to Runway 30, the G1000 NXi shows our airplane in an exocentric view, along with 3D buildings and signs in the synthetic vision display. Newman demonstrates a fully coupled autothrottle takeoff: The throttles smoothly advance to takeoff power, and we rotate at 95 knots. Throughout the takeoff and climbout, the autothrottle keeps the engine instruments in the green arcs; pilots can use the default interstage turbine temperature limits for these PT6A-52 turboprop engines or set their own limits between 760 and 810 degrees for an additional safety buffer.
During hand-flying, Garmin’s stability protection engages when pitch attitudes or bank angles exceed predetermined limits to nudge the airplane toward stable flight. For single-engine airplanes and normal twin-engine operations, the gentle pressure normally begins at 45 degrees of bank. In an engine failure in the King Air, however, bank limits shift to 40 degrees toward the operating engine and 10 toward the inoperative engine. Newman pulls back the power on the right engine, and the engine-out annunciation appears on the PFD as the roll limit indicators shift to the left on the attitude indicator. He hands me the controls, and I feel the resistance start at 10 degrees in a right bank toward the idling engine. Low-airspeed protection from the ESP also keeps the airspeed more than 15 knots above minimum control airspeed (VMCA).
It’s time for the Autoland demonstration. Autoland can be initiated by a guarded switch, activated automatically if a pilot is inactive for 20 minutes and doesn’t respond to a series of alerts, or triggered by prolonged activation of the ESP system. The Autoland system calculates the nearest suitable runway based on runway length, width, and surface; evaluates fuel, weather, and other factors; communicates on 121.5 MHz and the last tuned frequency; transmits to tower or CTAF at the destination airport; descends; and lands with no human intervention.
For our demonstration flight, the emergency transmissions and squawks are disabled so Newman communicates with ATC. Once he activates Autoland, the airplane turns toward the airport and begins a descent. The normal PFD and MFD layouts are replaced with a screen explaining that Autoland has activated and giving details of what’s happening: miles to the destination, fuel remaining, minutes to landing. Soon we’re lined up on final approach to Runway 21 tracking the RNAV approach.
The Autoland certification project began in 2018, and certification for a larger twin was more involved than for a single-engine turboprop.
“We had to deal with things like asymmetric thrust, you know, props that are going into their flat pitch range, especially for the flare,” said Garmin flight test engineer Will Johnson. “If they were to come back at a different rate, we had to make sure they were stacked up just right. There's lots of extra braking with two big propellers when you're coming in to land. So a lot of things like that. We had to make some big changes and improvements all around, and I'd say it all worked out pretty well.”
Garmin estimates Autothrottle installations for the King Air will be $50,000, and $100,000 for Autoland retrofits including the autothrottle. G1000-equipped aircraft also will need upgrades to the latest G1000 NXi.