Story ID: 071LearG5000AINSep12EditedByAY_NM
Garmin G5000 Adds Vision to Learjet Cockpit
By: Matt Thurber
Caption: 
Word Count: 1760
In mid-July, Bombardier made a flight-test Learjet 40 available to demonstrate the capabilities of the Garmin G5000 integrated flight deck that is a key feature in the new Learjet 70 and 75. This Learjet 40 is one of two flight-test articles flying in the 70/75 program and the first jet to fly with Garmin’s first Part 25 avionics suite, which is branded as the Vision cockpit for the Learjet application and the first Part 25 avionics system with touchscreen control. Judging from my one-hour flight, the Learjet 70/75 Vision cockpit clearly signals that Honeywell and Rockwell Collins face a keen new competitor in the Part 25 avionics arena. (Cessna has also selected the G5000 system for the Citation Ten, Longitude and Latitude.)

While pilots who are familiar with Garmin’s G1000 glass cockpit will feel right at home with the G5000/Vision system, the main difference between this and earlier Garmin products and also Honeywell and Rockwell Collins avionics is the pilot interface. The G5000/Vision system is controlled via Garmin GTC 570 touchscreens, one for each pilot, with little of the button pushing and knob twisting required on the G1000. G1000-happy pilots, however, can avail themselves of a volume control knob, map joystick and familiar Garmin dual concentric data-entry knobs at the bottom of the controller. The GTC 570 is part of the G2000 through G5000 systems.

Readers may have some understandable confusion with the branding trends for avionics systems. Gulfstream’s PlaneView flight deck is Honeywell-based in the large-cabin jets and uses Rockwell Collins Pro Line Fusion avionics in the G280. Bombardier has chosen the Vision brand name for the Global 5000 through 8000 and Learjet 85 with Rockwell Collins Pro Line Fusion avionics and also for the G5000 system in the Learjet 70/75. As much as I appreciate marketing and branding, I find this confusing and therefore will refer to the Learjet 70/75 avionics system flown for this article as the G5000. Rockwell Collins did confirm to AIN that it did not bid on the Learjet 70/75 package when Bombardier began working on the program about four years ago.

The six-passenger Learjet 70 and eight-passenger 75 will replace the 40 and 45 when they enter service beginning in next year’s first half. In addition to replacing the jets’ Honeywell Primus 1000 CRT-based avionics with the G5000 system, the new models feature new winglets that are canted out farther and Honeywell TFE731-40BR engines, each delivering 3,850 pounds of thrust with no automatic power reserve (APR) limit, up from the 40/45’s -20BRs at 3,500 pounds (3,650 pounds APR). Bombardier engineers were able to extract weight, about 200 pounds, from the new models from both the new avionics and airframe changes. Performance improvements include a 600-foot takeoff field length reduction, range of more than 2,000 nm and direct climb to 45,000 feet (maximum altitude is 51,000 feet).

Form Meets Function

In the cockpit, three WXGA, 14-inch, LED-backlit Garmin displays in landscape orientation replace four Primus 1000 CRTs, cleaning up the cockpit considerably and freeing up much space behind the panel. Chrome and leather finish adds a professional touch to levers and flight controls. The 5.7-inch GTC 570 touchscreens, also LED-backlit and with lower VGA resolution, fit nicely between the center panel and the console and are easily reached. The touchscreen controllers are a marked improvement, in terms of both aesthetics and functionality, from the typical control-display units in business jets.

Garmin’s human factors engineers spent a lot of time ensuring that pilots would still be able to do everything necessary during turbulence. The controller uses infrared beams that must be interrupted to activate an icon on the screen. This differs from capacitive touchscreens such as the iPad’s, which rely on actual touch to work. The advantage of the infrared touchscreens is that they can be calibrated to ensure button pushing only when desired. For example, a finger-thick poke is needed to select an icon on the GTC 570. A pencil is too thin and won’t do the trick. And multiple fingers don’t work, either, preventing an accidental swipe on the screen from making any changes. Wrong moves, including pushing one icon then sliding a finger onto another or poking at the intersection corners of multiple icons, elicit a thump tone to indicate that nothing is going to happen. Pilots can set click sounds for feedback after successfully pushing a touchscreen icon. A rubbery texture on the side of the GTC 570 bezel helps pilots stabilize their hands when using the controller.

Modern flight decks are all about stunning visuals and ease of use, and the new Learjet Vision cockpit achieves both goals handily. The G5000 system allows pilots to customize the layout using two-third and one-third split screens on the PFDs and center MFD, effectively splitting the instrument panel into six display areas. In addition to an attitude indicator with airspeed and altitude tapes for each pilot, the other four panes can display moving maps, approach and airport charts with own-ship position, checklists, system synoptics, Taws, Tcas, flight plans, weather radar and datalinked weather information.

While there are keys on the displays, pilots can control most G5000 functions via the touchscreen controllers and using the automatic flight control system mode control panel mounted in the eyebrow area and the two outboard controllers. This setup is far simpler, cleaner and less confusing than the typical G1000 configuration.

What simplifies the operation of the G5000 system is that so much capability is available on the touchscreen controllers. This includes radio tuning, mapping, traffic and Taws options, weather data selection, flight planning, approach procedures, charts, aircraft systems, checklists, telecom services and system setup. The weight-and-balance function is useful but lacks the ability to insert and remove weights in specific areas such as individual seats and baggage areas.

An excellent feature that is critical for touchscreens is the screen cleaning utility, which freezes the GTC 570 so it can be cleaned with a microfiber cloth without activating any icons. To protect the many switches on the center pedestal, Bombardier has added a cover that slips into place and is strong enough to step on when entering the cockpit.

Dual GMA 36 audio processors will eventually allow addition of text-to-speech capability, 3-D spatial audio and speech recognition. With this capability, pilots could, for example, on final approach say the word “wind” and the audio system would vocalize the wind speed and direction. Or pilots could ask the system to pull up the Nexrad radar picture or a specific approach chart. Adding these features will require installation of a text command switch, likely on the yoke, something that is on the roadmap for future upgrades.

New Radar Installed

Pilots should like the new Learjet’s radar, the first installation of Garmin’s new solid-state, turbulence-detecting GWX 70. Modern radars are moving exclusively to solid-state and away from the magnetron found in older systems. Solid-state radars need far less power to generate many more radar pulses than a magnetron. For example, the GWX 70 using 40 watts can output thousands of pulses a second, compared with the 100 pulses/second that a magnetron can deliver while using much more power. Magnetrons have significantly shorter lifespans, too, about 1,500 hours, according to Garmin. The GWX 70 is interfaced with air data computers and thus can maintain the same relative tilt angle even as the aircraft’s pitch changes. Advanced features include turbulence detection and ground-clutter suppression. For pilots who like to map the ground with radar, the GWX 70 does include a ground-mapping mode.

Other Garmin equipment includes dual VHF navcom radios and 24-channel Waas GPS receivers, a single ADF and DME, dual FMS, attitude heading reference system (AHRS), magnetometers and air-data computers and dual transponders with ADS-B out capability. A single Tcas II unit is installed, which meets the latest Change 7.1 mandate. Electronic charts are provided by Jeppesen (Garmin ChartView) and Garmin’s SafeTaxi charts for 600 airports are also now available for European operators. Optional equipment includes Garmin’s Iridium transceiver for voice calling, text messaging and receipt of Garmin worldwide weather data outside the U.S. and Canada, where XM does not work. An XM receiver is also optional.

The flight-test Learjet 40 that I flew is S/N 2129 and was still being used for autopilot development testing, so the final software load wasn’t installed yet. Some of the functionality not available during the flight included display of performance calculations and electronic checklists. Optional controller pilot datalink communications will be available to meet the European Link 2000+ mandate, upon EASA approval expected in next year’s second half. Fans 1/A capability will eventually be available, too. Another capability to be added is Garmin’s electronic stability and protection (ESP) system, which uses autopilot servos to apply a righting force when certain parameters in pitch and bank are exceeded. ESP can also help prevent stalls by lowering the nose when the aircraft reaches a critical angle of attack. At high speeds, ESP applies back pressure if the airplane gets too close to Vmo. The flight control system doesn’t have an automatic emergency descent mode.

Garmin director of flight operations and chief test pilot Tom Carr and I flew the test Learjet 40 at 17,712 pounds with the cg just inside the aft limit. (Mtow is 21,500 pounds.) We burned about 1,000 pounds during our one-hour flight to 16,500 feet over Wichita’s west practice area. Although the terrain around Wichita is fairly featureless, the sharp and colorful synthetic vision display on the big G5000 screens was something that I prefer keeping on in all phases of flight.

During the return to Wichita, my preference for the pane layout was to display the approach chart on the left one-third pane and the ADI in the right two-third pane on my PFD. Pilots can select their own profiles for panel layout and single- or dual-cue (cross-pointer) flight-director modes and save those settings for easy retrieval from the G5000’s memory.

Garmin displays the flight-path marker in this installation only when synthetic vision is turned on. The flight-path marker made flying this Learjet smooth and easy, especially during a hand-flown ILS approach to Runway 19 at Wichita’s Mid-Continent Airport. The marker is driven by the AHRS, not by an inertial reference system, as is the case on larger jets.

Landing the G5000-equipped Learjet 40 underscored the synthetic vision’s accuracy. As I looked up through the windshield on short final, the outside view perfectly matched what I’d been viewing on the Vision cockpit’s big display.