Avionics: Garmin Glass for King Air Class

So long, steam gauges!

February 1, 2008

Beechcraft King Airs have been enduring hits in their 40-plus years in production, proving that turboprop twins still carve a strong niche in the marketplace. That’s especially true for the 90-series King Airs. These entry-level turboprops—the so-called “baby” King Airs—have sold more than any other type of King Air. Recently, Hawker Beechcraft announced the new King Air C90GTi, a variant of this classic modernized with more powerful engines and a Rockwell Collins Pro Line 21 glass cockpit with three large display screens, traffic and terrain warning systems, XM datalink weather, and Jeppesen electronic charts.

That’s fine if you want a new airplane, but the many owners of older King Air C90As and C90Bs—as well as those flying the C90GTs built in 2006 and 2007—now have a retrofit glass cockpit option: Garmin recently obtained a supplemental type certificate to install its newest G1000 avionics suite in most of those airplanes. To qualify for installation, these C90As, -Bs, and -GTs must have triple-fed electrical bus systems, the Rockwell-Collins APS 65 autopilot servo brackets, and four-blade propellers. The triple-fed bus gives the G1000 optimum electrical power redundancy, the APS 65 brackets accommodate Garmin’s replacement autopilot servos, and the thrust of the four-blade propellers is compatible with the G1000’s GFC 700 autopilot/flight control system’s capabilities in maintaining prescribed stability parameters.

Airplanes with the Blackhawk or Superhawk PT6-135A engine upgrade can also be accommodated, as can airplanes having the standard PT6A-21 engines.

The retrofit is a high-end, full-featured suite that includes dual attitude heading reference systems (AHRS), dual Wide Area Augmentation System (WAAS) GPS units, a TAWS-B terrain awareness warning system (which includes obstacles), Garmin’s SafeTaxi airport charts and FliteCharts, XM WX datalink weather, Garmin’s GWX 68 weather radar, Garmin’s GFC 700 automatic flight control system, and TIS-B traffic information—all standard. L-3 Avionics’ Skywatch traffic advisory system is an option.

There are several noteworthy aspects to the G1000 King Air retrofit. The most obvious is the large, three-tube display setup, which includes two 10.4-inch-diagonal primary flight displays (PFDs) and a huge, 15-inch multifunction display (MFD). Describing the capabilities of each could fill a book, but to be brief, suffice it to say that the PFDs include vertical tape depictions of airspeed and altitude and have purple trend lines that predict the airplane’s airspeed and altitude in the next six seconds. There’s a mini-map inset display that calls up a thumbnail view of your track, nearby terrain, and other features, plus Nav, Comm, true airspeed, and a flight plan entry keypad (which is identical to those used in the Garmin 530/430 GPS units).

The MFD incorporates an integrated engine information system, which presents engine gauges—inter-turbine temperature (ITT), torque, prop rpm, turbine speed, fuel flow, and oil pressure and temperature—in a vertical stack to the left of the main display field. The MFD can be used to call up datalink weather, airborne weather radar imagery, expanded flight plan and navigation datasets, topography, traffic, high- and low-altitude airways, plus the SafeTaxi airport charts (which also can be displayed on the PFD), instrument approach plates, standard instrument departures (SIDs), standard terminal arrival routes (STARs,) and airport diagrams. The airplane’s position is geo-referenced on the charts, so you can follow your progress as you taxi, or fly through a holding pattern, procedure turn, or approach procedure. For those who haven’t experienced it before, this G1000 adds up to a huge boost in situational awareness.

A glareshield-mounted automatic flight control system mode controller—Garmin’s GMC 710—is used to input the sorts of autoflight commands you’d expect to find in a modern transport-category airplane. Commands such as flight-level change (FLC—to invoke constant-airspeed altitude changes), half-bank (for turns at high altitudes), altitude preselect (to set up target level-off altitudes during climbs and descents), yaw damper, and coupled vertical navigation (VNAV). Of course, there are also the usual modes—heading hold, approach, and nav track—and a choice of command bars or cross-pointers for the flight director function.

This G1000’s software upgrade—it’s version 8.2—enables autopilot-coupled VNAV as well as automatic procedure turn and holding pattern flying. The VNAV feature lets you enter crossing altitudes for fixes using the GCU 475 MFD keypad controller. Engage the autopilot, and the G1000 will fly a descent, then automatically level off at the selected altitude. The default descent angle is three degrees, but you can also manually configure a descent using another descent angle—or by entering a descent rate.

My flight in Garmin’s testbed airplane—a C90B—showed off the retrofit’s capabilities in spades. Garmin senior flight test pilot Tom Schaffstall showed me the ropes as we departed Garmin’s home airport at the Olathe, Kansas, New Century AirCenter, climbed to 16,000 feet, and leveled off. Entering a flight plan automatically calls up en route charts, complete with airways, so we tracked to a feeder fix for an ILS approach to Runway 33 at the Lawrence, Kansas, Municipal Airport. We entered step-down and crossing altitudes on the MFD flight plan page, loaded and then activated the approach, and engaged the autopilot.

The GFC 700 flew the route laterally and vertically as we neared the airport. Then we entered a holding pattern, joined the final approach course outbound, flew a procedure turn, and rejoined the localizer on our way to the decision altitude. The autopilot flew the entire profile—until I disengaged it to perform the missed approach procedure. To disengage the autopilot, I pressed the go-around button on the left power lever (it was the first time I’d touched the controls since 16,000 feet). The next step was to power up for the climbout and retract the landing gear.

At this point, the autopilot was ready to fly the missed approach procedure—including all turns, leveling off at published altitudes, and flying the holding pattern at the missed approach fix. All I did was press the AP button (autopilot engage), then press the NAV button on the glareshield panel. For someone accustomed to the missed approach drill for the Garmin 530/430, automation like this is a welcome workload reliever. So far, the software upgrade that permits the King Air retrofit’s coupled VNAV, automated holds, procedure turns, and missed approaches isn’t yet approved for installation in new airplanes—except the Cessna Mustang.

Garmin isn’t stopping with 90-series G1000 retrofits. It’s conducting a test program designed to certify a similar G1000 retrofit for the King Air 200 and B200 series of airplanes. Garmin says that this system should be approved by the end of this year. To date, four 90-series King Airs have had the G1000 conversion. Their lucky pilots now have the automation—not to mention the WAAS advantage of vertical guidance to LPV, LNAV, and LNAV/VNAV approaches—that until now was available only to those flying the Mustang. That airplane comes from the factory with the same G1000 avionics package as the retrofit.

The retrofit is priced at $350,000, which includes parts and labor. Garmin says that the work takes four technicians four days to complete. For those looking to bring their baby King Airs out of the steam gauge era, it may well be worth the wait.

E-mail the author at tom.horne@aopa.org.

Thomas A. Horne

Thomas A. Horne | AOPA Pilot Editor at Large, AOPA

AOPA Pilot Editor at Large Tom Horne has worked at AOPA since the early 1980s. He began flying in 1975 and has an airline transport pilot and flight instructor certificates. He’s flown everything from ultralights to Gulfstreams and ferried numerous piston airplanes across the Atlantic.