Avionics manufacturer Avidyne makes various FMS/navigator/radio systems that are designed to fit into existing avionics trays without any hardware modifications. Its IFD440, for example, is plug-and-play compatible with Garmin’s GNS 430W, and the same is true of the IFD540 and upcoming IFD550, which can be swapped into the tray of a GNS 530W. But aircraft owners buying the IFD units must pay an avionics shop to make the swap, check some configurations, run ground tests and sign off the installation. “Why can’t I swap my own box?” asked Avidyne president and CEO Dan Schwinn. “We designed the IFDs to be plug-and-play.”

After checking the applicable FAA regulations, Avidyne feels that wording in Part 43 should allow a pilot to perform such an installation on his or her own airplane, under the preventive maintenance regulations. Item 31 in Appendix A permits “Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, excluding automatic flight control systems, transponders and microwave frequency distance measuring equipment [DME]. The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, an operational check must be performed in accordance with the applicable sections of Part 91 of this chapter.”

So Avidyne put together a guide to show pilots how to perform the swap to an IFD unit, including configuration instructions and how to perform ground and flight testing as well as the sign-off. One caveat is that only existing WAAS GNS units can be replaced with an IFD. A non-WAAS GNS isn’t eligible for plugging and playing with an IFD, which includes a WAAS GPS sensor. Avidyne also tested the process with an FAA inspector, who did the swap/installation in an Avidyne lab then wrote a report for FAA headquarters to review. According to Schwinn, reaction from different FAA personnel has ranged from favorable to vehemently against the idea. But he feels confident that the FAA will not oppose this practice and that pilots will be able to do their own IFD swaps. 

This effort is not intended to take business away from Avidyne dealers, Schwinn explained. What this does is helps IFD buyers add a modern navigator to their panels, and then they will likely be interested in an ADS-B upgrade, which they will have to have installed by the dealer. “It’s a way to let people get started themselves,” he said. “You can put this in; then let the dealer do the rest of the ADS-B. Avidyne offers a money-back guarantee: if you put it in you can return it if you don’t like it. The odds are pretty good on this, and it’s a great way to say, ‘Try one of these things out.’”