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Garmin GFC500 autopilot, again?

For about a year ago we installed some Garmin Avionics in a C172. The customer was quite sure that they wanted a Garmin GFC500 autopilot in a couple of years or so we prepared the aircraft with the necessary wiring for the servo’s. Well now a year later the GFC500 was installed below a picture of the layout.

Aspen E5 EFIS / Garmin GNX375 GPS and ADS-B in/out xpdr

The old King KLN94 GPS and KT76C transponder was replaced by the Garmin GNX375 a combined WAAS GPS navigator and ADS-B in/out transponder. The attitude indicator, directional gyro and VAC system (dual VAC pumps) was removed and replaced by a Aspen Avionics E5 EFIS with “advanced features unlock” that includes OAT and winds. The GNX375 has an internal bluetooth transceiver and built in backup AHRS (requires an Ipad and the Garmin pilot software) so we also installed a RAM mount for portable electronic devices and a Garmin GSB15 dual port USB charger.

Garmin GFC500 autopilot in a Cessna 210

We have noted an increased interest in autopilots, not just any autopilot but the Garmin GFC500 that in it’s basic configuration has pitch/roll and automatic pitch trim as an option. Some aircraft may also be equipped with a yaw servo but that might seem like an overkill for small GA aircraft like the Piper PA28 that has a one axis roll Century IIB autopilot as standard. The GFC500 requires that the Garmin G5 EFIS system is installed and preferably a WAAS GPS navigator such as the Garmin GTN 650/750Xi series for full functionality.

Total system pricing for a roll/pitch/pitch-trim, dual G5 attitude and HSI with OAT option is about USD15k. Installation cost varies depending on the complexity of the servos and standard PA28 series with battery in the tail section being the easiest. PA28R series are much more complex since the servos are located in the most AFT tail section and very hard to reach.

Is is difficult to estimate installation time since it may include the removal of VAC system, complete rework of pitot/static system and re-doing the existing installation.

The picture below is from a C210 with a GFC500 pitch/roll autopilot with pitch trim option. The attitude indicator was kept in the panel since the aircraft has de-icing so the VAC/Pressure pump can not be removed.

G5 and Avidyne?

The Garmin G5 is a non TSO part and must be installed in accordance with an EASA STC. The G5 STC defines all compatible units and the Avidyne IFD series are not listed. However the recent revision of the Avidyne STC lists the G5 as an approved display for the IFD440 series. We also installed a JPI EDM730 engine analyser with EGT/CHT/FF/RPM/Carbtemp sensors, 2 ea Appareo Stratus Power panel mounted USB chargers and a MaxPulse Wing tip LED landing light controller. The aircraft had an older GMA340 audiopanel that was replaced for a Garmin GMA345 audiopanel with automatic squelch, bluetooth interface and  USB charging port. The existing TT31 Mode-S transponder was connected for ADS-B out. The installation looks simple but is a combination of 4 ea EASA STC’s, 1 ea grandfathered FAA STC, 1 ea EASA Minor change and additional CS-STAN for those items not covered by STC’s.

GTN750Xi in a Cessna 152

When we say Cessna we think about the 172 series.. however the picture below is from a C152 and includes dual G5, GTN750Xi, GMA35c bluetooth audio panel and FS510 WiFi module for wireless database updates. A Trig TY96 as COM2 and Trig TT31 Mode-S / ADS-B out transponder small form factor makes the panel complete.

Garmin GI275 digital indicator

The GI275 is available in 3 different versions. All indicators have capacitive touch screen with Bluetooth/WiFi. FAA certification and STC with AML (approved model list) is already completed and we are now waiting for EASA validation.

BASIC is used as a CDI or EIS (engine indication system). ADAHRS (air data attitude heading reference system) is used as a AI (attitude indicator) or HSI (horizontal situation indicator). ADAHRS + AP (autopilot)  is the same as the ADAHRS version but with outputs capable of driving a third party autopilot.

Depending on which version you choose additional accessories such as internal battery backup, OAT probe, magnetometer or engine adapter may be required.

The most recent software updates allow the GI275 to replace an existing VAC driven attitude gyro in an installation with a Century II/III autopilot.

For more information and detail click this link – click here

The GI275 received an EASA Approval with limitations (validated FAA STC) late december 2020.


Aspen Series EFD1000/E5 vs Garmin G5

Which one should I get? What’s the difference?

First the most obvious, Aspen screen size, the direct access buttons, knobs. The Aspen E5 is a NON TSO product based on the EFD Series TSO platform while the G5 started out as an “experimental” and now approved for certified aircraft.

The Aspen is capable of interfacing with older avionics utilizing composite signals and in a simpler installation using modern avionics and without an autopilot you don’t need any extra boxes. The G5 is a dual unit system, so the benefit is that even if one display goes black you still have ALL functions left in the other. You will need and external box that translates NAV signals to CAN bus signals that the G5 can understand.

G5 is plastic fantastic vs the Aspen aluminium casing but the G5 CAN bus makes the Garmin G5 versatile – 2 wire system interface with compatible equipment like the Garmin GFC500 autopilot. G5 and OAT will require a separate GAD29 OAT interface while the Aspen Avionics has both OAT and backup GPS built in the remote sensor module.  Aspen has a better “user experience” and SVT synthetic vision… so the answer which one to go for?

Note regarding the Aspen E5. The E5 will require “advanced features unlock” to be able to show OAT and winds (about USD500) but then again you don’t need any extra modules or probes. The E5 will only support 1 ea GPS/NAV receiver such as a GTN650 or GNS430 due to the lack of ARINC ports (the E5 has 2 ea unlocked Arinc inputs compared to the Garmin GAD29B that has 4 ea inputs).

Garmin G3X Touch EFIS display now EASA certified.

In March 2019 Garmin announced that the Garmin G3X Touch system had received FAA approval in accordance with FAA STC SA01899WI that allows the non-TSO EFIS system to be installed in certified aircraft. Now more than one year later Garmin announced that the FAA STC finally has been validated by the EASA. The STC installation manual is about 500 pages and the basic installation manual  for non certified aircraft is close to 1000 pages suggesting that the installation of a G3X will require careful planning and that the installation cost will be significant as it will affect the whole instrument panel and most likely require a complete rework of all avionics. For aircraft not limited to VFR a Garmin G5 EFIS must be installed as a backup standby instrument adjacent to the G3X EFIS display.

For more information refer to:

Garmin GTN750Xi next generation COM/NAV/GPS

In 1997 we installed some top modern avionics like the Garmin GPS155 XL in this Saab MFI 15. Now 23 years later its time again (registered as experimental). This time a well needed “cleanup” behind the instrument panel and the installation of a Garmin GTN750Xi series COM/NAV/GPS with a Garmin Flight Stream 510 WiFi/Bluetooth module and remote audio panel / intercom / marker receiver Garmin GMA35c with Bluetooth capability. The VAC system was removed and the mechanical gyros were replaced for dual Garmin G5 Attitude and HSI indicators with a GAD29B ARINC adapter (required for interface with the GTN750Xi) and also GAD13 OAT module.

Garmin GPS175 (WAAS/LPV)

In 2019 Garmin announced the GPS175 (GPS), GNC355 (GPS/COM) and the GNX375 (GPS/XPDR ADS-B in/out). The EASA approval was completed in november 2019.  All units feature built in Bluetooth interface (two-way communication with the Garmin Pilot software), WAAS GPS with LPV (localizer performance vertical guidance) approaches. The user interface is very similar to the one found in the big brother Garmin GTN650/Xi series COM/NAV/GPS navigators.

The picture below shows a Cessna 172 that was upgraded with a Garmin GMA345 audiopanel with Bluetooth interface, Garmin GPS175, Garmin GNS430 COM/NAV/GPS, Garmin GTX330 Mode-S transponder. The installation was done in such way that it would be easy to upgrade the GNS430 to WAAS and the GTX330 to a GTX330 w/ES (ADS-B). The installation also includes Garmin G5 Attitude and HSI with GAD13 OAT module. We have prepared the aircraft with wiring for a Garmin GFC500 autopilot.  A “RAM” mount was installed in the copilots side to hold a portable device.