This month’s panel for planning is an easy one that starts with a clean platform that already has the basics covered. It has a utilitarian but reliable Mode C transponder with the solid-state Garmin GTX 320A unit, plus a remote Garmin ADS-B Out transmitter.
Its new owner—working toward her private pilot’s certificate—is looking to boost the reliability, performance and supportability of the existing equipment. This includes traditional spinning gyros and a TKM MX300 digital navcomm radio. The TKM was designed as a direct replacement for the original ARC RT300-series VHF navcomm, using the existing wiring and VOR indicator. TKM went out of business a couple of years ago, so support for the already aging radio might be difficult.
While this aircraft won’t see any hard IFR, an avionics package that can support the growing pilot’s knowledge of the IFR system—including WAAS GPS approaches—is a good plan looking to the future. Moreover, she has invested in a new Bose A30 headset, but the existing Sigtronics SPA400 intercom is utilitarian at best, so maybe a basic audio panel with Bluetooth capability can offer decent utility when flying with a passenger or instructor, while increasing the quality of the audio. Let’s get to work.
GPS and RADIO IN ONE
Focusing on the radio stack, a good option might be Garmin’s $7895 GNC 355 GPS/comm. With a 2-inch-tall bezel, it’s smaller than the MX300, so space certainly won’t be an issue.  While the GNC 355 is designed to drive a variety of third-party nav indicators, the existing ARC VOR head won’t work because it doesn’t have a VDI required for precision GPS approaches. A few options here, including Garmin’s GI 106B, which has everything required to fly WAAS GPS approaches. It replaces the popular GI 106A, and at a price tag just north of $3000, there are better options for this airplane, which might be better served with an electronic HSI to replace the vacuum-driven directional gyro. Let’s move to the pilot’s panel and look at a worthy alternative.
Mini-EFIS
Without question, replacing the spinning attitude and directional iron gyros (and removing the vacuum system) and replacing them with electronic solid-state gyros will breathe some modern tech into this old bird. It’ll also offer a boost in useful load—always welcomed in a two-seat trainer. Two options come to mind, the first from uAvionix, with a couple of AV-30 instruments.
The $2299 AV-30-C (the C is the certified version) can serve as an attitude instrument with a ton of other features including AoA, audio alerting, altitude alerting and primary slip indication. You wouldn’t even have to modify the plastic panel overlay—the AV-30 is the same footprint as the old gyros. A second AV-30-C serves as an EHSI and at press time, uAvionix released a major upgrade to the AV-30’s EHSI capability thanks to external smart adapters. The new uAvionix AV-HSI smart converter accessory adds long-awaited utility to the previously lacking AV-30 IFR interface, with support for IFR GPS navigators to display GPS vertical and lateral course guidance.
A couple of AV-30s with the GPS adapter and magnetometer might run somewhere around $7000, installed. Add that to the GNC 355 (roughly $10,000 installed), plus a budget-priced Bluetooth audio panel/intercom, and you end up with a light-IFR-capable trainer equipped with the latest gear.
Got a panel that needs planning? Drop us a line with some good photos and we’ll take a look.
