Cessna 172 Dual G5/GTN Upgrade to meet IFR requirements


The co-owner of the C-172P contacted us with an avionics upgrade request to meet the conditions for IFR operation. The aircraft was equipped by only few modern avionics solutions such as Garmin GTN650 and Garmin GTX328 IFR navigation. The rest of the aviaonics was the original avionics of 1986 production.

After a brief discussion, we found perfect avionics solutions which met the customer's requirements and at the same time were not expensive. Instead of the artificial horizon and the gyro compass we installed a pair of Garmin G5 certified, the old KMA-24 audio panel was replaced by a modern GMA 345 with bluetooth. Garmin GNC 255A COM / NAV transceiver was installed to meet the condition of two 8.33 kHz radios. The navigation equipment was completed by the DME receiver KN-62A containing a harmonic filter, which is required for operation in Europe.


Since the bulk of the radio rack was going to be changed, we offered the customer to replace the existing cabling that was unsatisfactory after various modifications. Thanks to the aircraft inspection before installation, we could prepare the cable harness without having to ground the aircraft in our hangar and shorten the installation time to the airplane by one week.


After the aircraft was delivered, we immediately started work. The first step was to remove the old cabling and install the new ready-made one. The new cabling was withdrawn into the common bundles compared to the existing one and protected by a shrinking tube. During the dismantling we also removed the old unused radio, which created extra unnecessary pounds. Subsequently, the old radio rack was removed and a new one was inserted.


Since one of the CDIs was not used, we replaced it with an artificial horizon to make it a backup device. During the installation we made the faceplate to cover the empty space after removed avionics and cut precise holes into the plastic cover to accommodate the two new Garmin G5.


10 days after the start of the installation, the aircraft was ready for the first ground tests associated with GMU 11 magnetometer calibration. After ground tests,  the new avionics were tested and the transponder and altimeter measurements were taken to ensure that the avionics system met all conditions to remove VFR restrictions from ARC.


Completion of the development took place 4 days after the ground tests. During 4 days  the overvoltage warning light in the on-board network was repaired, the audio jacks were replaced for stereo and all release documentation was approved and GTN 650 software was updated. During flight tests, issue with GS indication on G5 and GI-106 was discovered and  traced down to the original coaxial splitter, which was defective. Thanks to the inventory of the AIR TEAM company, the replacement of the splitter for a new one was accomplished within an hour, and on the second test flight, the GS receiver was twice as sensitive.cessna_7

Petr Babák, owner of the OK-CLL aircraft: Although I was initially slightly worried about the integration of the new avionics at the AIR TEAM service, as it was their first project in the new LKTB hangar, the huge professionalism of the entire team was confirmed during the entire project Modernization of my airplane's avionics was done quickly, very well and efficiently. I especially appreciate the fact that they did not invent nonsensical extra work compared to other services and did not charge every small thing, but on the contrary they tried to improve my aircraft even at their own expense. It is undoubtedly a great advantage of the background of the parent company AIR TEAM, both in access to avionics inventory and long-term cooperation with avionics manufacturers and access to technical information, STC and training.

Are you considering similar avionics upgrade? Do not hesitate to write to us and we will contact you immediately with an individual quote. In addition, we offer a 30% off seasonal discount during the summer months.