JetTech Moves Citations into the Modern Age

 - April 26, 2021, 9:00 AM
JetTech's CitationJet 525 avionics upgrade replaces the original avionics with modern Garmin touchscreen TXi displays, GTN650/750 navigators, the GI 275 electronic display as standby, and the GFC600 autopilot.

While legacy Cessna Citations may meet mission needs for range, payload, and operating expense, many lack an avionics suite that can take advantage of the latest in approach capability, situational awareness, and communication technology. But as is often the case, the manufacturer of the existing avionics doesn’t offer an upgrade for these legacy jets, although in all other aspects the jet meets the owner’s needs.

This is the scenario that JetTech, based at Rocky Mountain Metropolitan Airport (KBJC) in Broomfield, Colorado, has elected to resolve. Since starting the company almost 20 years ago, Rob Irwin and his team have dramatically expanded the operational envelope of Citations and other aircraft by developing a series of avionics solutions. Irwin—who has a background as a military fixed-wing and rotorcraft pilot along with A&P mechanic and inspection authorization certificates—started working on RVSM in the early 2000s. His efforts resulted in the development of RVSM solutions for a wide variety of turbine aircraft, including many Citations.

Irwin’s company expanded from its original RVSM STCs and by 2010 started offering Garmin G600 displays in the Citation 500 series, interfaced to GNS 400/500 series GPS navigators. In 2013 JetTech obtained an STC to install dual G600s and touchscreen GTN 750 navigators in Part 23 Citations in the 500 series. At that time, the existing copilot instruments had to be retained on Part 25 Citations due to the FAA requirements for Level A hardware and software, which wasn’t available in the G600. All of these STCs allowed integration with the Sperry SPZ 500 autopilot, through a proprietary JetTech adaptor. More than 400 Citations in the 500 series took advantage of these STCs.

JetTech then moved to the Cessna Citation 525 series, starting with the original CitationJet. The initial STC for this series was only for the GTN 650/750, which I’ve flown, and it is a significant improvement, replacing the Universal FMS and the GNS 400. This upgrade expanded the CitationJet operating envelope by providing ADS-B using a Garmin 345 transponder, and because it included WAAS capability, it added the all-important LPV approach approval with autopilot coupling. The JetTech STC included an interface that sends the appropriate vertical guidance signal to the Sperry SPZ 5000 digital autopilot, enabling the use of the APR button for LPV approaches. The STC also provides an option for a handy glove box where the Universal FMS used to reside. 

JetTech
The JetTech Garmin upgrade greatly simplifies the CJ's panel. (Photo: Rich Pickett)

TXi to CitationJet

Not content with offering only that STC for the Citation 525, JetTech embarked on adding the latest Garmin products to the CJ series. With the advent of Garmin’s new touchscreen TXi displays, Xi versions of the GTN 650/750, GI 275 electronic display, and GFC 600 autopilot, the CJs were ripe for the creation of yet another STC. JetTech purchased its own CJ to facilitate the development of an expanded STC to replace the legacy avionics. The company’s CJ was invaluable in this development, and Garmin test pilots spent about 100 hours flight testing that jet.

I’ve flown numerous aircraft, including my own, with the Garmin displays and GTN navigators as well as CJs with Collins Pro Line 21 and Garmin G3000 avionics. It was interesting to fly JetTech’s CJ equipped with the TXi and other avionics with Rob’s son Chris to evaluate the latest offering. The JetTech CJ is a beautiful example of how a legacy aircraft can be upgraded to the latest standards. When you enter the flight deck, the simplicity and capabilities of the upgraded avionics are immediately apparent.  JetTech’s technicians did a complete renovation of the panel and not by just shoehorning in the new products. All of the aircraft systems and their associated switches along with the engine gauges and N1 computer are still present, but the rest of the clutter is gone.

While it doesn’t have the minimalistic style of the latest Citation M2 or Citation CJ3+ and their G3000 avionics, the modified CJ is clearly more ergonomic than its predecessor, which was equipped with a mix of various manufacturers’ products, most of which are now obsolete. I also find that having knobs and switches for some functions is actually more efficient, and ergonomic, than relegating all functions to a touchscreen.

The panel is outfitted with two 10.6-inch Garmin G600 TXi touchscreen displays, two GTN 750Xis, GTX 335R/GTX 345R transponders, the GFC 600 autopilot, an integrated audio panel, a GDL 69A SiriusXM weather and radio receiver, a GSR 56 Iridium phone and weather datalink, GWX 75 radar, and the GI 275 electronic flight instrument as a standby. JetTech’s CJ also has a third VHF antenna for future-proofing to accommodate CPLDC if Garmin incorporates that capability in the GTNs.

The GI 275 is a highly configurable display. It can be installed with various options from a PFD, to an HSI, or engine indicating system. The GI 275 in JetTech’s CJ is configured as a combined HSI and PFD, featuring synthetic vision, standalone GPS, and backup battery power so it acts as an effective standby instrument. Even the clocks are replaced with Mid-Continent’s MD93 solution, which includes dual USB power ports. It felt like a new airplane. 

Rich Pickett
Pilot and VLJ owner Rich Pickett flew JetTech's CitationJet to learn more about the jet's Garmin avionics and autopilot upgrade.

Flying the Modified CJ

When Garmin developed the TXi displays, it added many features similar to the G3000/G5000 products. The display clarity alone is a significant improvement, along with luminosity that is three times greater than on earlier displays. The new capabilities require more processing capability, hence the incorporation of dual-core processors. These sophisticated displays leverage the technology, including touch-capabilities, of the Garmin GTN series navigators, resulting in seamless integration with the GTN 750Xi.

Before starting the engines, Chris and I reviewed various G600 TXi configuration possibilities, from split-screen to full-screen display with an expansive view of the detailed synthetic vision. All functions are crystal clear and bright, and the synthetic vision provides a near-3D experience. In my flying with sophisticated displays, I vary the configuration depending upon the phase of flight. I can split the G600 TXi display and view a PFD and terminal procedure for arrivals and departure, then switch to a multifunction panel in cruise.

Configuring and programming the avionics suite is simple and intuitive. While this equipment does not have the systems integration and checklist of a G3000/G5000 installation, all the other capabilities for flight are present. Entering a flight plan is quick, either through the GTNs or using a split-screen on either G600 TXi. Our flight was relatively simple, with a departure from KBJC to Greeley and then back. With our flight plan loaded and the N1 computer set, we were ready to fly.

On departure, I experimented with a full-width G600 TXi offering synthetic vision across the screen. The situational awareness in this configuration is amazing and useful when flying at night, in low-visibility, or in mountainous terrain. After departure, I switched to a split screen with the multifunction panel displayed as my default. This allowed me access to virtually all of the GTN functions directly in front of me. When I wanted to display only PFD functions, it took just a press on the screen-split function icon to switch back. The panel essentially has six configurable panels, offering even the most energetic pilot more than enough display options for all phases of flight.

Garmin’s GFC 600 autopilot performed flawlessly in all modes, including the helpful LVL button, which offers immediate recovery to a straight-and-level flight mode from an unusual attitude. The GFC 600 also features over- and under-speed protection to avoid maximum airspeed exceedances as well as low-speed excursions when approaching stall speeds. The GFC 600 features an IAS speed mode, which is equivalent to the FLC mode on other autopilots. 

When we were returning to KBJC and entering the Denver Class B airspace, I split the G600 to display a highly visible map featuring the complex airspace sectors, aiding in situational awareness. The GTNs and G600 TXi support LPV approaches, something that wasn't available in the legacy CJ avionics. Once I'd loaded the RNAV RWY 30R, which was a simple process, I split the G600 TXi to display the approach procedure chart on my right panel. As Denver Approach vectored us, I activated the approach on the GTN 750 in anticipation of approach approval. Once that was obtained, a single press of the APR button on the GFC600 transitioned us to the final-approach course. As expected, the entire process was seamless.

Installation Considerations

JetTech develops the STCs and, while it will do some installations to perfect the process, the company works primarily through Garmin’s network of authorized aviation dealers. JetTech provides the dealers with a kit, which includes the engineering drawings, technical data, AFM supplement, maintenance documents, technical support information, and of course the STC. The length and cost of the installation process depend upon several factors, including the available options.

With an estimated 80 percent of the Citation CJ fleet having implemented at least one of JetTech’s GTN STCs, there are ample opportunities to easily move up to the latest offerings, as well as initial installations. Within the Citation series, beyond the CJ, I wouldn’t be surprised if JetTech uses its extensive experience to put current and future Garmin equipment into additional models.

With the long lifespan of turbine aircraft airframes and engines, the ability to extend the capabilities of legacy jets is important for their continued utility. JetTech’s innovative engineering solutions over the years have significantly improved the usefulness of these aircraft. The current offering for the Citations brings the latest technology to the flight deck, further enhancing the value and safety of these useful airplanes.