Used Airplane Gotchas: The Little Things

Everyone should know the cardinal rules of buying a used airplane, which of course starts with doing a suspicious prebuy evaluation through a shop or mechanic who has no stake in the sale. In fact, bring it to someone who doesn’t know the airplane or the current owner at all. But I continue to shake my head when I hear stories from new owners who get hosed in a deal that could have been avoided with a closer look at systems that are often neglected. Here’s a short list of gotchas that can ding an already stressed budget within the first year or less of ownership. With any luck, you might save a bunch of money by calling these things out at the negotiating table.

Pitot-Static Systems

As simple as it may seem, pitot-static system repairs for many aging airplanes are what big invoices are made of. Whether you plan to fly the airplane VFR or IFR, insist on taking delivery of the plane with both FAR 91.411 and 91.413 inspections accomplished. For VFR, you only need to have the transponder certified (91.413), but I always advocate maintaining the system to IFR standards, which includes doing 91.411 static pressure and altimeter certification. A friend who recently bought an old Cessna that was represented as “IFR ready” wasn’t even VFR ready because both 91.411 and 91.413 were years overdue. This was a big red flag (and made me ponder how the rest of the airplane was maintained), because I know the static systems in old Cessnas can be prone to leakage as static lines and fittings get brittle. It’s not a huge deal if the system is regularly maintained and lines and fittings are incrementally replaced as needed, but when the many feet of static plumbing develops leaks, it takes major disassembly to troubleshoot and fix. In some Pipers, it could mean removing a fuel tank to access one of the pilot lines that ultimately joins up with the pitot mast under the wing.

In the case of my friend’s old Skyhawk, the airplane wasn’t even legal to fly home because the transponder (and ADS-B unit) weren’t certified. When I called it out, the broker in the deal bellyached but agreed to bring the plane to an avionics shop to have both 91.411 and 91.413 inspections completed. But when my friend showed up to close the deal (two weeks later) and bring the airplane home on a 700-mile trip, he found that only the transponder was signed off. When asked why the rest of it wasn’t done, the broker backpedaled and said the shop ran out of time. When the plane went to the shop back at home base, it meant paying $850 to finish the inspection. It could have been worse if the shop found leaks. Luckily it passed.

Finally, look carefully at the last 10 years of these inspections in the logbooks, which should be five entries since the inspections are required every two years. Is there an altimeter correction card? Is there evidence that the system was well maintained by repairing any leaks? Many are pencil-whipped—not the right approach for a system you’ll fly in the weather. Don’t assume that since the airplane was upgraded to electronic flight instruments that the checks aren’t required—they are, and are even more important because the digital instrument’s accuracy relies heavily on a tight pitot-static system.

As covered in a recent article, pull an FAA ADS-B Out Public Performance Report. It’s an easy way to uncover any problems that exist in the ADS-B system’s transmission before it becomes your problem.

Antennas

This is another source of big invoices, and many antennas on aging airplanes are simply neglected. Airplanes that are parked outside without good cabin covers that slip over the top antennas (usually communications antennas) are susceptible to antenna damage. Most comm antennas are made of fiberglass and these are very easy to inspect. Look for any cracking in the antenna’s carcass, especially along the base of the antenna. The problem is that water can intrude in the area of the antenna’s base and the skin of the fuselage, which builds corrosion. Left untreated, this might require a major structural repair to the skin.

At the least, poor antenna health leads to poor system performance. With comm antennas, this might mean static buildup when flying through wet clouds and precipitation. It can also reduce transmit and receiver range, plus scratchy transmissions. With GPS antennas, a big no-no is painting them because it messes with the frequency and resulting satellite reception. Good paint shops know to remove antennas when doing a new paint job, but some take shortcuts and spray over them. Look at the aircraft’s belly and make sure transponder and ADS-B antennas are in good shape. They take a beating on the underside because of engine oil/grime blowby, and fiberglass transponder blade antennas installed too close to an exhaust stack can melt.

I’ve seen comm antenna replacement invoices top several thousand dollars and even more on pressurized airplanes. Look them over carefully before signing on the dotted line.

Avionics Inspections

This is something that doesn’t happen nearly as often as it should, no matter how complex or simple the avionics are. Don’t leave it up to the maintenance shop or mechanic doing the prebuy because they might not know what they’re looking at. A huge opportunity to spend a small fortune is with autopilot problems. While you really don’t know how well the system is going to perform until you fly it, there are some things you can do to tell if it works. A sad story comes from a hangar neighbor who bought a twin with an aging King system. The shop doing the prebuy work spent so much time looking at the engines, but no time with the autopilot. He ended up hand-flying the airplane home across the country—in the weather—because the autopilot wouldn’t hold altitude. He was startled when the system ran the pitch trim to the stops and ended up pulling the circuit breakers. The shop that looked at it quoted almost $9000 to fix it, so he bit the bullet and had a new system installed. The previous owners (through the broker …) swore it worked the last time he flew the airplane two years prior.

Have a qualified shop check the comm radios, GPS receivers, audio jacks, and even the avionics cooling system if equipped. Check the instrument panel lighting and dimmer circuits. If the previous owner never flew the aircraft at night, how would they know the lighting didn’t work correctly?

But other problems might not be so obvious, including a subtle display failure on a Garmin GNS 430. Garmin can’t get replacement displays, which makes the unit a throwaway if it needs a replacement. But other more common problems can be pricey to address if the unit has to go back to Garmin for a flat-rate repair. In the case of the long-discontinued GNS navigators, where display lenses and bezel buttons are common wear items, a trip to Olathe, Kansas, can yield an invoice close to $2500, not counting shop labor. Look at the bezel lens for signs of fading and damage from someone cleaning it with a solvent, and make sure the nomenclature on the bezel keys is readable. The same is true for aging BendixKing KX155 radios, where display repairs can cost a couple thousand dollars. These are all items that can be addressed when you’re negotiating a sell price.

Paperwork

For aircraft with STC modifications, and even major repairs and alterations, the right paperwork can make or break a deal. For most aftermarket systems governed by an STC, there will likely be a flight manual supplement that essentially becomes an extension of the aircraft’s flight manual. It includes the STC permission, limitations, instructions for continued airworthiness, normal and emergency operating procedures, and other important aspect of the modification. In many cases, this will be a lot of work for a shop to replicate—and a real hassle if the installation was done via FAA Field Approval, which is a one-time STC. A sharp shop or mechanic will look carefully at the aircraft’s paperwork, and it might take the help of an avionics shop to make sure all of the supporting paperwork is in place for the avionics installed in the airplane. I know a buyer who paid a shop $2500 to make a replacement paperwork package for all of the retrofit avionics that were in the airplane because the flight manual supplement was lost. If you’re an airplane owner, guard this paperwork as carefully as you do the aircraft maintenance logs.

The prebuy inspection is also a good time to make sure the weight and balance data is up to date and accurate. If there’s any doubt, arrange for the seller to have the airplane weighed. It’s not a bad idea for any aging airplane because face it, you want to know exactly what it weighs and where the loading data stands.

Final Thoughts

I always advise buyers to look hard at the airplane and come up with a list of improvements they would make in the first couple years of ownership, especially avionics. If it doesn’t have the package you want, or missing stuff you would put in yourself, send a trusted avionics shop a few photos of the panel and get a quote for equipment you would buy yourself. While you’re at it, ask the shop if it spots any potential problems with the existing stuff. All of this can be brought to the bargaining table. The problem is that many buyers get caught up in the emotional side of buying their own airplane. I call it airplane goggles—and it’s a risky mindset.

Independently, a lot of the items on my short list here are small potatoes compared to the purchase price of most airplanes. But added up, it’s real money at a time when the budget is usually stretched far beyond what many new owners planned. Imagine draining the bank account to bring home the airplane of your dreams and then having to come up with many thousands of dollars more on stuff that could have been deducted from the sell price if only you spotted them. That’s a real buzzkill in the world of new-to-you airplane ownership.