Other than having to write big checks, one of the toughest things about aircraft upgrades, including avionics retrofits and paint work, is dealing with the downtime. Shops tend to be optimistic in estimating completion times when trying to close the sale. And when it’s finally time to fly, expect some debugging, tweaking and maybe a couple of runs back to the shop. Pick one that’s reasonably close to home. I got to thinking about the heartburn when an owner called and asked the simple—but impossible to answer—question of how long his airplane should be in the shop for a Garmin avionics project. I certainly wasn’t qualified to give him an accurate answer because it wasn’t me who had his airplane all over the hangar floor—for four months. That’s a long time for the proposed GPS, big-screen EFIS and ADS-B transponder installation. While it was in, the radar was shipped for repair and a maintenance shop was changing the brakes. Four months? No way.
The aircraft is a pressurized piston single and the shop never really committed to an exact downtime, but figured it would be down for a few weeks, “more or less.” That might have been a red flag, or not. I’d plan on four weeks for that project. But the big red flags came on week six when he showed up to find the airplane not in the work hangar, but in a transient tiedown spot across the field. Looking into the cabin he could see the new equipment was in, but the interior was mostly removed and there were still some holes in the panel and worse, holes in the fuselage (covered with tape) where new antennas were to go. When asked what was up with his airplane, the shop manager said the schedule was behind after the ADS-B rush, plus it had closed for a bit during the pandemic. That’s fair, but the shop never called him off, and the owner got the plane to the shop a bit early. Behind the scenes, the shop was dealing with outside engineering approval for some antenna work that required drilling through the pressure bulkhead. Mental note: If you bring a pressurized aircraft to a shop for major work, it’s worth asking if it has the in-house capability to sign off modifications to the pressure vessel. If it doesn’t, what are the costs and expected downtime to get the approvals to make it legal. Many shops don’t have the capability in-house.