In the 1990s, fourth-generation airliners introduced fly-by-wire (FBW) technologies with active flight envelope protections. The impact on airline safety was impressive—FBW has reduced the number of loss of control in-flight (LOC-I) accidents by 75 percent and cut the overall accident rate to 0.1 accidents per million flights.
Today, nearly all newly certified air transport and business aviation aircraft employ some form of these technologies. In general aviation, manufacturers are rapidly embracing concepts such as envelope protection in the latest turboprop singles and light jets.
Earlier this month, the Piper M600 SLS became the first aircraft to secure FAA approval for the emergency-use-only Garmin Autoland system. Garmin Autoland is part of Piper’s multi-layered safety system, which it calls HALO, integrated into the M600’s Garmin G3000 flight deck. Other HALO features include an autothrottle, automatic level button, hypoxia recognition with emergency descent mode, and enhanced stability.
This is significant for general aviation, as it demonstrates a leap in technology that Piper, and other OEMs—namely Cirrus Aircraft and Daher—are incorporating into their flagship general aviation aircraft to enhance safety and efficiency.
The Garmin Autoland system is used during an emergency when the pilot is incapacitated. A passenger activates the system via a button on the flight deck. Garmin Autoland then takes control of the aircraft and communicates with air traffic control and the passengers while monitoring external parameters (weather, terrain, airport database, approach capabilities, etc.) to identify the nearest suitable airport.
Once the airport is identified, Garmin Autoland flies a GPS-based instrument approach, lands, stops on the runway, shuts down the engine, and provides instructions to the passengers on how to disembark from the aircraft.
The highly integrated G3000 avionics suite with its digital autopilot and autothrottle systems enable the autoland feature. Several other aircraft systems are modified to safely configure the aircraft for landing, stop it on the runway, and secure it after flight. Electronic relays are added to activate the flaps, landing gear, and landing lights. An emergency braking system is used to stop the aircraft on the runway, while an electronic fuel shutoff valve will shut down the engine.
The Garmin Autoland system will soon be certified on the Cirrus Vision Jet and Daher TBM 940, which are also equipped with G3000 avionics. Cirrus labels the Garmin Autoland system “Safe Return” and it is part of the Vision Jet’s Perspective Touch+ integrated avionics system. Daher uses “Home Safe” for its emergency autoland system and it is a function of the TBM “e-copilot” system. In general, Garmin Autoland functions are similar on each aircraft type.
In addition to emergency autoland, other G3000 features improve flight safety by addressing other, more prominent, threats such as LOC-I and runway excursions and incursions.
Electronic Stability and Protection (ESP) is a passive flight envelope awareness tool that prevents the onset of stalls, steep spirals, and loss of control. ESP utilizes smart autopilot sensors (when the autopilot is disengaged) to “nudge” the stick or yoke when the aircraft approaches bank angles or pitch attitudes that are outside of the normal flight envelope. The concept is akin to the active flight envelope protections on larger jets and provides a feedback mechanism when a limit is approached. The main difference is that ESP, as a passive system, allows the pilot to override the system as needed or desired.
Likewise, under-speed protection (USP) is another Garmin autopilot function that alerts the pilot to an impending stall and lowers the angle-of-attack to increase the stall margin of the aircraft.
Another Garmin feature that is available on several aircraft is the “Blue Level” button. The level button is used during a LOC-I event to return the aircraft to a stabilized wings-level flight attitude. This system was first certified on Cirrus SR-series pistons.
High-performance turbine-powered aircraft operate at optimal altitudes in the Flight Levels. Thus, the G3000 also has an emergency descent mode (EDM) to prevent an accident from a hypoxia-induced incapacitation. By monitoring the aircraft pressurization system, EDM will sense a high cabin altitude and initiate an emergency descent to reach a lower—oxygen filled—altitude. In addition to descending to a safe altitude, the transponder will automatically squawk 7700 (the emergency code).
Finally, the G3000 suite incorporates several features that enhance a pilot’s situational awareness; these include synthetic vision, SafeTaxi, and SurfaceWatch. SafeTaxi is georeferenced to display “own ship” position on a highly detailed airport surface map to avoid runway and taxiway incursions. SurfaceWatch provides cues to direct the pilot to the proper runway and ensure that there is enough runway surface available to land; this helps mitigate the runway excursion threat.
Obviously, the greatest safety feature on any aircraft is a well-trained pilot, but it is always nice to have a little help. Garmin Autoland is brilliantly engineered and demonstrates advancements in avionics, autonomous flight, sensor, and servo technologies. It is important not to understate the significance and importance of this technology—it is utterly amazing—and how these systems make general aviation safer.
Pilot incapacitation is rare; however, this system provides an assurance to a passenger in a single-pilot aircraft that the aircraft is recoverable. Likewise, these advanced avionics suites provide an added layer of safety to avoid more prevalent threats such as LOC-I and runway incursions/excursions.
Pilot, safety expert, consultant, and aviation journalist - Kipp Lau writes about flight safety and airmanship for AIN. He can be reached at firstname.lastname@example.org.