I recently managed to take care of one of the items on my wish list, and I did so at a significant discount.
April 2015-
Back in the day, all I wanted was a new Nav/Com, a wing leveler and an engine that didn’t leak too much oil.
Times changed, and my wish list got more expensive. Now it includes a new GPS-based flight management system (FMS), a new autopilot with all kinds of GPS-enabled capabilities—and an engine that doesn’t leak too much oil. (Along with a new paint job!)
I’ve recently managed to take care of one of the items on my wish list: the replacement of a 37-year-old autopilot with something modern. I’d been using a Century III autopilot with altitude hold and Nav/GPS/localizer tracking—no glideslope coupler, no altitude preselect, no beep when the autopilot kicked offline. (On the other hand, when the Century III worked, it was amazing.)
After flying with Century III and Century 41 autopilots for over 40 years, I had grown accustomed to this quiet, invisible and completely reliable equipment flying the plane for long hours at a time.
The need for a reliable autopilot
For those of you that have never flown a Seneca, here’s my one-sentence summary of its flying attributes. It is highly stable, but it can be a bear to fly.
That is, it’ll fly for long periods of time on-heading and on-altitude with the autopilot offline, my hands in my lap and my feet flat on the floor. After a while it will slowly drift left or right, up or down. The drift is so slow that if I’m not careful, I’ll bust my altitude and have to account for my poor flying habits. Every few minutes you have to roll left or right a bit, or pitch up or down a bit.
Here’s the bear part: roll and pitch forces in a Seneca are not light as in other Pipers. You cannot pitch or roll with just a few fingers on the yoke; it takes your entire fist wrapped around the yoke to make the change. Hence the need for a reliable autopilot.
Century III and Century 41 autopilots are as reliable as any autopilot can be. My 37-year-old airplane was in need of autopilot maintenance for the first time just last year, and that caused me to do quite a bit of research and soul-searching.
A variety of tasks
With help from my A&P mechanic and my avionics shop, I determined that completing a variety of tasks would resolve my autopilot problems.
What my airplane needed first was to have its aileron and elevator cables replaced, along with an inspection of all of the pulleys and other fittings used by these cables. The old cables were stretched and worn, as were the pulleys and fittings.
In my experience, the peace of mind after a complete check of the flight controls is worth any amount of money. Whether you’re updating your autopilot or not, if you haven’t done this already, I would recommend a flight control cable check at your next annual—especially if you have an older airplane. (For more information about AD 2013-02-13 and Piper Mandatory Service Bulletin 1245A, see Steve Ells’ Questions and Answers column on page 20 of this issue. —Ed.)
After I had the cables and fittings inspected and replaced as necessary, I had my plane re-rigged. We adjusted the flaps, ailerons, elevator and elevator trim so that the airplane would track straight and level just like it did when it was manufactured. An unexpected benefit of this was that my Seneca flew about three knots faster afterward.
After all of the flight control changes, the next step in my troubleshooting process was to retry the same autopilot. With heading and altitude hold enabled, the airplane still slowly rolled left and right—just a couple of degrees. Pitch varied as well: it was a constant couple of degrees up and down.
I asked my avionics tech what we could try next, and he told me we could overhaul each autopilot device one box at a time until the problem was resolved. With three servos, one autopilot computer, the controller panel, a radio coupler, an attitude indicator and a directional gyro, that approach would certainly be a big undertaking.
For a second opinion, I contacted Autopilots Central in Tulsa, Okla. The person I spoke with said that I could either purchase a new, modern autopilot for $25,000 to $30,000, or the company could overhaul everything to do with my existing Century III which would cost about $10,000 and take about a month.
Neither of these suggestions appealed to me. First of all, $25,000 to $30,000 wasn’t in my budget; and the idea of spending $10,000 to overhaul a 37-year-old autopilot wasn’t very appealing, either. (I’d just spent $2,500 to replace the flight control cables and miscellaneous parts.)
Frustration and envy
At this point I was frustrated and didn’t do anything for about a month—other than research the features, benefits and costs of new autopilots. An S-TEC System 55X starts at about $25,000 plus installation and other options; the Century 2000 starts at about $19,000 plus installation and other options.
Ultimately, I decided what would be most advantageous in my Seneca was an attitude-based, not a rate-based, autopilot. That ruled out an S-TEC unit.
Several weeks later I went back to my avionics shop and there was a Seneca of the same year getting a brand-spanking-new Century 2000 autopilot with GPSS and altitude-preselect.
I’ll admit it. I was envious.
I went back two times that month to watch the installation and discuss autopilot options for my airplane. On my third visit, the Century 2000 installation was complete, but the shop was having difficulty making it work correctly.
Over the next two months, the owner of that Seneca got frustrated and had the Century 2000 removed. He installed a new S-TEC 55X.
My opportunity
This was the opportunity I was hoping for. I expressed my interest in buying that Century 2000 even though it was removed from the other Seneca because it didn’t work correctly.
I figured as long as the price was right, I could spend a few bucks making it work and still be ahead on costs. But my radio guy advised me not to buy a used autopilot because I wouldn’t be able to get the necessary paperwork (STC) or installation kit.
Again, I went home frustrated.
Somewhat discouraged, I called Century—and to my surprise, they were willing to sell me an installation kit and STC for the new/used Century 2000. I went back to talk to my radio guy, and he said I should go for it.
I explained to the autopilot owner that I was willing to offer $8,000 for his new/used system. Having been told by Century that $4,500 would buy the STC and installation kit, I was cautiously optimistic that I could afford to purchase the autopilot at that price.
Of course I had forgotten to calculate the installation cost for this new/used autopilot. Installation added another $5,000, and my airplane was down for two months. Then, when it was finally time to test-fly my airplane, guess what? The autopilot didn’t work any better on my Seneca than it did on the other Seneca!
Repairs under warranty
My radio shop sent the servo, autopilot computer and attitude indicator to Century Flight Systems for repair, as the parts were covered under warranty.
Century’s technicians found a couple of manufacturing bugs and sent the items back, fully repaired and operational—at no cost—several weeks later. We put the servo, computer and attitude indicator back in, and the airplane flew almost perfectly with the new computer.
Flying the Seneca was better… but not good enough. Even though the new Century 2000 autopilot was functioning much better than my old Century III, it still had a tiny roll left and right and a tiny pitch up and down.
At this point, I was financially way ahead—but not yet quite pleased with the autopilot’s operation. My radio guy scratched his head and looked over the installation for a couple of weeks but couldn’t find anything wrong.
Century Flight Systems HQ
Not wanting to live with this problem, I contacted Matt Greer, foreman of aircraft maintenance at Century Flight Systems in Mineral Wells, Tex. Greer was amazingly helpful.
He advised me to make sure that all of the electrical connectors and all of the vacuum hoses on the attitude indicator were tight. Following his advice seemed to help, but again, not quite enough.
Greer then invited me to fly the plane to Century’s headquarters and offered to find and fix the problem there.
About two weeks later I arrived in Mineral Wells (KMWL). Greer dropped what he was doing, pulled my plane in the hangar and checked everything. He removed my attitude indicator and had it overhauled right on the spot.
While the AI was being overhauled, Greer checked all of the electrical and vacuum connectors. Then he discovered an errant piece of plastic where the autopilot computer was inserted into the rack. The computer was out of its socket by about 1/8 inch.
After Greer trimmed away the plastic, he reinstalled the autopilot controller and reinstalled the just-overhauled attitude indicator. Then we took the airplane for a ride.
The autopilot worked—and continues to work—perfectly. I thanked Greer for his help, paid a small bill for the service and flew home.
I suspect that the issue with the untrimmed plastic on my installation was the source of the issue for the first owner of the autopilot. Perhaps if that Seneca owner had been a bit more patient, the Century 2000 would have been as perfect for him as it is for me.
Ultimately, my patience resulted in a new Century 2000 autopilot with roll and pitch mode, auto trim, GPSS (roll steering), altitude preselect, an NSD-360 HSI and an attitude indicator. While it took a very long time, I saved over $10,000—and I learned a lot.
Piper Flyer Association member Scott Sherer is a multi-engine and instrument rated private pilot. He’s logged 2,600 hours and is the owner of a 1977 PA-34-200T based at Burlington Municipal (KBUU) in Burlington, Wis. Sherer anxiously awaits the day when N344TB finally gets new paint. Send questions or comments to editor@piperflyer.org.
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Century Flight Systems, Inc.
centuryflight.com
1-800-433-5630
