There are many avionics upgrades available for general aviation aircraft, ranging from a single electronic flight instrument (say, an attitude indicator) to a full glass cockpit makeover. We consulted with Garmin on options for the AOPA Sweepstakes Grumman Tiger and narrowed our choices down to two: retrofitting the existing panel with a four-pack of Garmin GI 275 electronic flight instruments; or installing an entirely new instrument panel to create a glass cockpit featuring Garmin G3X Touch flight displays.
Some pilots are not convinced a glass cockpit is for them; they prefer the familiarity of analog gauges but appreciate the advanced capabilities of electronic flight displays. Others just don’t need an entire glass cockpit upgrade. In these situations, replacing one or more analog gauges with Garmin GI 275s may be the logical choice. GI 275s match the form factor of 3-1/8-inch round analog gauges. The ability to easily swap out analog gauges for digital instruments fosters panel upgrade flexibility in most older airplanes. You can start by upgrading what is arguably your most critical instrument: the attitude indicator. By doing so, you gain increased situational awareness and remove one link from the vacuum pump failure chain—while adding the security of an optional 60-minute battery backup. Add a few more GI 275s (horizontal situation indicator, engine indication system, and multifunction display versions are also available), and you have much of the functionality of a glass cockpit with minimal disruption to your existing instrument panel. Add more than two or three GI 275s, however, and your equipment and installation costs can equal or exceed larger flight displays, such as the 7-inch G3X Touch. You’ll want to do a cost comparison to determine which upgrade route makes the most sense for your situation and budget.
Although the GI 275 option was compelling, we will install a full glass cockpit in the sweepstakes airplane. A new instrument panel will be filled with two Garmin G3X Touch flight displays (a 10-inch primary flight display and a 7-inch multifunction display), a G5 back-up attitude indicator, a GMA 245 audio panel, a GNX 375 all-in-one GPS navigator and transponder with ADS-B In and Out, a GNC 255 back-up nav/com radio, a GMC 507 autopilot control panel, and two GSB 15 USB chargers containing a total of four charging ports.
With our plan confirmed and the required equipment ordered from Garmin, the AOPA Sweepstakes Grumman Tiger was delivered to J.A. Air Center in Aurora, Illinois. Soon after arriving, the Tiger was stripped of its avionics, engine gauges, and all associated wiring. The mass of antiquated equipment and wiring weighed an astonishing 62 pounds (the wiring alone weighed 12 pounds). The new avionics weigh a mere 17.3 pounds, increasing useful load by at least 32 pounds and providing significantly more reliability. Because electronic flight displays do not require vacuum to function (as certain analog flight instruments do), the vacuum system will be removed, saving more weight.
Even the Tiger’s fuel gauges were removed, since G3X Touch flight displays includes fuel quantity indications. CiES Inc. fuel sending units will replace the stock units to provide increased accuracy and reliability.
The old 121.5 MHz ELT will be replaced by a new 406 MHz unit by ACK Technologies Inc., its satellite-based emergency locator signal significantly narrowing the search area for any rescue teams trying to find a missing aircraft.
We’ll demonstrate the capabilities of the new glass cockpit as soon as the Tiger takes to the skies again.