Most aircraft profiles start out with a long dissertation on the history of the aircraft’s type and its lineage—blah, blah, blah—okay, so here’s what you need to know to set the stage for this story.

The PA-23 Apache/Aztec was the first twin-engine aircraft built by the Piper Aircraft Company, and between 1952 and 1981 they turned out nearly 7,000 of them. Of all of the surviving airworthy Aztecs, the one owned by father and son partners Jerry and David Naylor is, without a doubt, the coolest, most technically advanced of them all.

Pretty heady praise indeed—but believe me, it’s well deserved. The partners have invested a stack of money and an incredible amount of time in bringing their 1978 Aztec F up to 2008 functionality, reliability and safety.

I was too polite to ask just how much they’ve invested, but as David Naylor explained it, when they told Bob Ferguson, manager of Autopilots Central, Inc. in Tulsa, Okla., about their ambitious plans for the Aztec’s Chelton and Garmin avionics upgrade, Ferguson’s response was pretty telling. "Well, if you ever want to sell it, you better sell the avionics and tell them it comes with two free engines," Ferguson said.

The perfect fit.

Sorry, I’m getting a bit ahead of myself here. Before we get into what the Naylors did, let’s visit a bit with David Naylor and find out why they did it.

"I grew up flying with my father, Jerry. He’s had his pilot’s license since 1945 and is still actively flying today," Naylor said. "In fact, at 81 years young, my dad is buying his 14th airplane—a new 2008 Flight Design CTLS LSA."

The younger Naylor has had his license since 1978 and has since gone on to add his multi-engine and instrument ratings. To date, he’s amassed some 1,800 hours of total time as pilot in command. The Naylors use their Aztec F for both business and pleasure flying. That combination is the catalyst for their extensive upgrade project.

"This is our third Aztec. We bought it in 1990 and have enjoyed flying it for the past 17-plus years. It’s an awesome airplane for us," Naylor said. "When my dad transitioned to his first twin, he did it in a Twin Comanche. It’s a neat little plane, but you had to be on top of it all the time. It could get ahead of you pretty fast. Dad wanted something more forgiving and, along with that, he decided he really needed a six-place airplane to haul the family and an occasional load of seeds."

"It was an FAA examiner who actually pointed him toward the Aztec," Naylor continued. "He said that bar none, the Piper Aztec was the safest, most forgiving twin in the sky. That’s what dad was looking for—safe, forgiving and fun." (With a dirty stall speed of just 55 knots, the Aztecs were arguably the most docile six-place piston twins ever built.)

Obviously Mr. Naylor found what he was looking for in the Aztec; anyone who buys three of anything must be satisfied. "Dad and I both just absolutely love it," Naylor said. "For what it may give up in streamlined looks and top-end speed, it more than makes up for it in usefulness."

That usefulness has served the family business well on more than a few occasions. "We’re [Naylor Seed Company] in the field seed business and we’ve actually hauled seed to and from many locations," he continued. "We’ve taken all the seats out and loaded it up with bagged foundation seed from Indiana and hauled them back here to Scotch Grove [Iowa]. That’s not uncommon."

But as much as they loved their trusty Aztec F, its systems were starting to become less than reliable. The Naylors did their share of window shopping, but always came to the same conclusion. "There’s just nothing new out there than can match our Aztec for comfort and load carrying capability—not without spending a couple million anyway," Naylor said. "More importantly, at my dad’s age, the last thing he wants is a different airplane. He can fly the Aztec almost with his eyes closed." (A practice Piper Flyer does not recommend.)

So they decided to give their beloved Aztec F a panel upgrade. You know the usual, new radios, an audio panel. Pretty standard stuff. So they thought, anyway….

The best laid plans…

"We were having all kinds of avionics issues with the original stuff," Naylor said. "Between the old radios and autopilot, every time I flew it one or two things would not work. It was all intermittent. I didn’t even want to fly it anymore."

Trips to Autopilot Central had become commonplace. And it was during one of these trips that the Naylors decided to get a quote to upgrade their avionics. That’s when things took a dramatic turn. "We were getting ready to replace the stack with a complete Garmin panel—340 audio panel; 530, 430, 330 transponder—we were looking to replace all the old stuff," Naylor said. "While they were working on the estimate, I picked up an AOPA flier that showed the Commander Sweepstakes plane with the Chelton glass in it."

"I looked at the picture and asked, ‘Why we couldn’t do that to our Aztec?’ And that’s what started it," Naylor said.

"So, with the help and advice of Shannon Curran, Pres. of Flight Management Group, Inc. of Utah, we put out bids and elected to go with Tim McCandless Avionics in Waterloo, Iowa. Turned out it was their first experience with installing the Chelton system.

Since the Electronic Flight Information Systems (EFIS) they planned to install would be the signature piece of the entire system, the Naylors chose the top-of-the-line 3D Synthetic Vision system with Chelton’s Highway-In-The-Sky (HITS) capability.

The 3D Synthetic Vision is the only FAA-certified version of Chelton’s FlightLogic system. It shows a forward-looking 3-D image that conforms accurately to the terrain ahead giving the pilot optimal situation awareness. According to Chelton, the display conforms so closely to the actual terrain view that it’s been called "VFR-IFR Equivalence."

The Naylors also included Chelton’s HITS, which makes it simple to program and fly even a complex flight plan. "The system is just amazing," Naylor said. "This is a whole new way to fly instrument approaches. It’s so much more intuitive than the ‘old’ way. You basically just keep the airplane symbol in the box and you’re flying the precise course or approach."

Back to the future

"David’s dad has flown Aztecs for a lot of years and they decided if they can’t buy a new one, they’d make this one as good as they could," explained Tony Will, Avionics Manager at Tim McCandless Avionics. "We pretty much accomplished that. This 30-plus-year-old airplane is as close as you can come to anything coming out of the factory today.

Other than the basic outline of the panel, there isn’t much left from what rolled out of Piper’s plant in 1978. "We pretty much gutted the panel. I don’t think we’ve ever gone that deep into an airplane before," he added. "You do a basic autopilot or GPS installation all the time—this was so much more involved than that."

Will said that after they met with the Naylors and looked over their Aztec, the next step was to put together a detailed game plan. "This was our first Chelton installation, so we had one of our main technicians go through the Chelton school. That was really important. Without that, it would never have worked. That’s something that Chelton requires and I understand why they do," Will said. "It’s a complicated installation and you need to know what you are doing to get everything correct."

Let the fun begin…

"We actually installed the Chelton displays, a Chelton autopilot and the Garmin radios initially," Will said. "The Chelton autopilot did not work out. They had too many problems with the pitch servos. Chelton discontinued the product and refunded the money. We couldn’t put the old Century autopilot back in—that’s one of the reasons they did the upgrade in the first place."

By chance, David Naylor had met with Greg Plantz, S-TEC’s Vice President of Sales and Marketing, during EAA AirVenture Oshkosh 2005. "The guys at the avionics shop, as well as some other pilots recommended the S-TEC Fifty Five X autopilot," Naylor said. "They talked up its performance and reliability, plus it had Altitude Pre-Select. I really wanted that feature."

The only problem was there was no available STC to install the S-TEC Fifty Five X in Naylor’s Aztec F. While that would have deterred many an owner—the FAA’s STC process is notoriously laborious and time- and money-consuming—team Naylor, along with Curran’s guidance, wasn’t going to let that get in their way. Fortunately, S-TEC was interested in obtaining just such an STC for their popular Fifty Five X autopilot.

"The Naylors, along with all other Aztec owners, love their airplanes but until now, have been unable to enjoy the reliability and functionality that they will get with a modern autopilot," Plantz explained. "By replacing their legacy autopilot with a new System Fifty Five X, they can enjoy the advanced capabilities and peace of mind that comes with having a high-performance autopilot in their aircraft."

Plantz said that along with the overall improvement in reliability that comes with a brand-new autopilot, the S-TEC System Fifty Five X also gives Aztec owners a host of features and capabilities that were unavailable in previous autopilot options including GPSS (GPS Steering), Altitude Pre-Select, Vertical Speed Control, Control Wheel Steering and more.

"GPSS is one of the features that has helped make S-TEC’s System Fifty Five X the most popular aftermarket autopilot in General Aviation," Plantz said. "By taking commands directly from the aircraft’s GPS navigation system, the GPSS function permits the autopilot to not only precisely fly en-route GPS courses, it also does an excellent job of precision flying GPS approaches, missed approaches and any other phase of flight where the System Fifty Five X is ‘flying’ the airplane."

While David Naylor appreciates all the features his new Fifty Five X brings to his Aztec, he admits to having two favorites. "The two things I love most about the S-TEC autopilot are the Altitude Pre-Select and the simple fact that it works," Naylor said. "Our old autopilot was worn out. We battled with it a lot just trying to keep it alive. I have total confidence that the Fifty Five X is going to work."

"The autopilot’s Altitude Pre-Select capability eliminates another thing a pilot has to do. In the past, ATC would tell me to climb to 9,500 feet and the next thing I know I’m at 10,000—I forgot to level off. I get busy with the GPS or charts or whatever," Naylor added. "With the Altitude Pre-Select function, I set the altitude and it climbs to it. It does it for me—I just love it. And it gives me a couple hundred-foot warning and automatically reduces the rate of climb as it approaches the selected altitude. When it levels off it just says ‘altitude.’ It’s awesome."

"It’s the same with the descent—I dial in an altitude and the rate-of-descent and as I approach that altitude, it automatically reduces the descent rate
and levels off," Naylor explained. "I enjoy a nice smooth transition. It’s a great peace of mind and security feature."

While using their beloved Aztec to get the FAA STC on the autopilot was time consuming, it wasn’t as much of an issue as was first thought. "We did the initial installation here and then it went down to S-TEC in Mineral Wells [Texas] and they did the STC part of it," Will said. "Overall it took about six weeks, but a lot of that was due to weather."

"David and his father were very gracious in allowing a lot of time for both the installation of the Chelton displays and the new autopilot," he added. "I’d say their investment was well worth it."

Everything old is new again.

Installing the two Chelton Synthetic Vision Displays, the new Garmin stack and S-TEC System Fifty Five X autopilot would seem like plenty for an avionics shop to accomplish, "But," Will said, "there was more to the project."

"We decided to take out the old radar. It had some issues and the repair costs were so far exceeding the value of the unit. We did take the opportunity to go ahead and do the wiring for an XM weather receiver for David," Will explained. "It’s ready to go. For now though, he has the Garmin 496 and he really likes the weather display on that. But if he wants to switch to XM down the road it’s already wired. It was easier to go ahead and do it while the interior and panel was taken out than to go back in later on."

"About the only ‘original’ things left in the panel are the engine instruments," he added. "And we left the Stormscope in. Other than that, it’s pretty much all new stuff."

Was it worth it all?

The one question I—and all of you—would ask is, "Was it all worth it?" The money? The time without the airplane? All of it?

"Absolutely!" Naylor said. "It took longer than expected, but we couldn’t be happier. Along with an amazing airplane, we have built some great friendships throughout the project."

"The Chelton displays are amazing. I am extremely impressed with them. They are an awesome update for safety and situational awareness," he added. "The airplane is safer and a real pleasure to fly."

Tony Will shares that sentiment. "I tell you what, we went and flew it the other day again and it’s great! It’s a really neat system—the Chelton displays and the S-TEC autopilot—we did a couple ILS approaches and stuff. I tell you if you’re doing the WAAS approach and the ILS, you are actually flying the ILS, but you are superimposing the Chelton WAAS approach. That thing flew in the boxes all the way down. Wow!

"I have a lot more to learn about the Chelton system and I’m looking forward to it," Naylor said.

"We are currently awaiting software updates so that our Autopilot/Flight Director will capture the Vertical guidance (VGP) for the GPS and WAAS approaches. Currently the only vertical guidance we have to the autopilot is the ILS/GS and VSI modes. We want to have the autopilot to be able to select between source one and two, just like the corporate jets. We have been told the upgrade is on the way—hopefully soon."

"And with that said, the airplane is a real pleasure to fly. I feel more confident and more aware than I ever have in an airplane before. Would I do it again? I sure would!

Dale Smith has been in love with airplanes and flying forever. A prolific aviation journalist, along with Piper Flyer, Dale writes for Plane & Pilot, Pilot Journal, Aviation Maintenance Magazine, Avionics News, Professional Pilot, Aviation Business Journal, Flight Training and other aviation magazines. When he’s not writing fun stuff about airplanes, Dale is also a principal partner in Flying Boat Creative Services, an advertising agency specializing in aviation.