Helicopter Flight Control System Is a First for Garmin

 - February 22, 2018, 1:08 PM
The new G500H TXI displays add touchscreens to helicopters, but they have knobs for those who prefer that interface. (Photo: Garmin)

Garmin has unveiled its next foray into flight control systems, the new GFC 600H. It's designed to build on what the company has learned with fixed-wing autopilots and deliver new safety benefits to VFR and IFR helicopter operations. Garmin also announced a full suite of its new G500H TXi touchscreen displays for rotorcraft, as well as upgraded G1000H NXi helicopter integrated flight decks.

“We’re working hard to bring this type of technology to the helicopter world,” said Jim Alpiser, director of aviation aftermarket sales. “For so many years, the rotorcraft world has been underserved from a technology perspective. That’s why we have made the investment we did with flight displays, the G500H. Now we’re updating to the new TXi and new flight control technology. This takes what we’re doing in the helicopter world to a whole new level.”

The first certification program for the GFC 600H and TXi displays is in Garmin’s Airbus AS350B2, and the design work and installation was done at Garmin’s Salem, Oregon facility. The 600H will be offered for VFR and IFR helicopters, and the VFR system will be first to market, with certification estimated in the fourth quarter this year. The TXi displays should be certified at the same time, but these will be done via an approved model list (AML) STC in a variety of helicopters. Autopilots aren’t certified via the AML process and must be approved for each helicopter model.

The GFC 600H three-axis flight control system now installed in the AS350B2 consists of a servo installed in parallel to the controls, which is simpler than the linear-actuator-based system that will be featured in the IFR-stability augmentation system. The yaw axis “is novel for light helicopters,” Alpiser said. “When in hover, if you engage the yaw axis it will hold the current heading. In cruise it holds the aircraft in trim so the ball stays in the middle.” A collective position sensor is tied to the system so that the flight control system automatically moves the anti-torque pedals when the pilot moves the collective.

For pilots, the parallel servo system is designed to make flying easier while allowing full control of the helicopter. In fact, the flight control system can be switched on during takeoff and landing. The system’s basic mode maintain’s the helicopter’s attitude, and provides force feedback when the pilot deviates from the attitude. “It’s a fly-through system,” he explained. “You push it out of the detent to move to a different attitude, then release it and it returns to that attitude.” A four-way or force trim switch on the cyclic is used to adjust to the new attitude.

A unique feature of the GFC 600H is that it incorporates Garmin’s Electronic Stability and Protection, which includes a “LVL” button that returns the helicopter to straight-and-level flight from unusual attitudes, as well as overspeed protection, limit cueing, and low-speed protection. “We hope no one has to use these features,” said Garmin flight test manager Sean Doyle, “but we hope they will.”

The GFC 600H adds other features that “might be found in larger helicopters,” he noted. For example, hover assist or ground-position stabilization, which helps the pilot stay in a hover, “even in strong and gusty winds.” In the basic attitude-retention mode, the helicopter will maintain the same heading, even if not in heading mode and even if disturbed by a gust. When coupled with a Garmin PFD, the GFC 600H can capture a selected altitude. A flight director is optional, another feature available with the Garmin display. However, the GFC 600H can be installed by itself, without a display.

GFC 600H lateral modes include heading select, nav, and approach. Vertical modes are indicated airspeed, altitude, altitude select, and vertical speed. A beep switch on the cyclic is used to adjust some of the settings for vertical modes, such as vertical speed.

Components of the GFC 600H include a GFS 83 force-trim servo, GMC 605H mode controller and flight director computer, GSU 75H ADAHRS (for standalone installations without a Garmin display), and a collective position sensor. Total system weight is 13 pounds.

Touchscreen Displays

The TXi displays for rotorcraft replace Garmin’s G500H system, with three different options: the GDU 1060 10-inch landscape, the GDU 700P portrait, or the GDU 700L landscape displays ( the latter two are seven-inch sizes). The key difference with TXi is that they are touchscreen displays, although they include concentric knob controls for an alternative to touchscreen input. Both the 10- and seven-inch displays offer Garmin’s HSI map, which was introduced on the G1000 NXi. The HSI map can display Garmin’s Wire-Aware wire-strike-avoidance information. A PFD controller is optional, adding more non-touch controls for pilots who prefer button and knob interfaces.

A new feature for the TXi that wasn’t available in the G500H is data logging, and this data can be downloaded wirelessly or via SD card. Another new TXi feature is crew profiles. Installation is easier with new configuration tools that allow export of configurations to entire fleets.

Garmin plans to obtain an AML STC for the TXi displays on the Bell 206 and 407 and Airbus AS350B2 and B3 and EC130B4 and T2.