It’s not like there aren’t already options on the market for Cessna 172 owner/operators who want all the Skyhawk’s pilot-friendly familiarity with the added benefit of a fuel/money-saving diesel power plant. So why would Premier Aircraft Sales—who’s already busy selling new Diamonds and Mooneys, as well as a portfolio of pre-owned piston and turbine aircraft around the world—want to introduce the Premier Edition 172 upgrade and jump headlong into the diesel retrofit business?
“We have customers all over the world, and they all share a common problem when it comes to fuel: Avgas is either way too expensive, or it’s not available at all,” explained Premier’s Vice President of Operations, Art Spengler. “So it’s pretty obvious to us that diesel power is the only way to go if we want to continue to sell them airplanes.
“Premier is in the very unique position to have a sister company, Premier Aircraft Service, that’s not only a Part 145 repair station, but also a Cessna-Authorized Service Center and the only Master Installation Center in the U.S. for the Centurion (now Continental) series turbodiesel engines,” he said. “There is no way we could have offered this upgrade program without having their capabilities in the next hangar.
“We also have the flexibility to custom tailor each Premier Edition 172 to meet the owner’s exact requirements with regards to avionics, interior and paint,” Spengler stated. “An individual owner may want the complete soup-to-nuts upgrade, and a flight school or banner-tower may want just the engine swap. We can do whatever they want.”
Spengler said that the standard Premier Edition 172 conversion includes the factory-new Continental CD-135 turbodiesel engine, Full Authority Digital Engine Control (FADEC), a new three-blade constant speed propeller, Garmin G500 glass and a GNS750 touch-screen GPS/COM/NAV avionics upgrade, and new leather interior.
Spengler said that while the Premier Edition currently features the 135 hp CD-135, they’re awaiting FAA and EASA approval to amend the STC to allow the installation of the more powerful 155 hp CD-155.
“Our shop is pending approval as an EASA 145 facility, and once we have that, we can install the CD-155 on aircraft going to anywhere but the U.S.,” he said. “We’re also hoping to have the FAA approval for the same installation in the next couple of months.”
Spengler said that while the CD-155 has 20 additional horsepower thanks to an improved fuel rail design, its fuel economy numbers are within mere percentage points of the 135 hp version.
In addition to the Premier Edition’s standard equipment, Premier offers its customers a plethora of options including cabin air-conditioning, AmSafe Airbag Seat Restraints, Micro AeroDynamics Vortex Generators and more.
|The firewall-forward installation of the Continental diesel and FADEC takes three weeks at Premier’s facility.
“Again, we differentiate our program by giving owner-operators the ability to specify the exact equipment they want,” Spengler said. “We do not try and push a one-size-fits-all solution on them.”
When it comes to the thing that really matters, Spengler explained that swapping out the 172’s gas-gulping Lycoming and putting in a 135 hp Continental CD-135 liquid-cooled turbodiesel is by far the most complex part of the entire project.
“It’s stripped from the firewall forward. And because the engine’s radiator has to go in place of the standard battery, we have to relocate that to the baggage compartment. That means we have to drill out all the rivets and remove the flooring to run the cabling to the engine,” he said. “That’s where being an authorized Cessna Service Center is a benefit. We can use the opportunity to make sure all the control cables and pulleys under the floor are up to the manufacturer’s specifications.”
Also, since the airplane’s interior is obviously gutted to remove the floor, Spengler said that the standard Premier Edition 172 upgrade includes a fresh annual inspection. “We’ll be able to touch things you just won’t see during a routine annual,” he said. “If the owner wants, we can even do a very thorough application of a corrosion inhibitor under the floor.”
Spengler explained that all the work is done at Premier’s shop at Fort Lauderdale Executive Airport (FXE). As for downtime, he said the typical engine conversion, including modification to the panel for the FADEC controller, takes about three weeks. Add another week to 10 days for avionics work.
If You Convert It, They Will Come
Spengler said the worldwide reaction to Premier’s announcement of its Premier Edition 172 upgrade program has been very promising. “Since we announced the program back in February, we’ve had over 175 inquires from 18 different countries around the world,” he said. “India, Panama, Trinidad, Angola, South Africa, the Philippines, Europe—you name it.
“We haven’t had, nor did we expect, much initial interest from here in the U.S. The delta between the cost of Avgas and Jet A is too small to really make the diesel conversion attractive,” Spengler said. “Now, if you look at those parts of the world where it’s a three-to-six-dollar spread between Avgas and Jet A, or in areas where you can’t even get Avgas, well, the Premier Edition 172 looks like the only way to go.
“We have one that’s going to Angola as a banner-tower, and the ability to run on Jet A is the only cost-effective option that operator has,” he said. “We also just demonstrated the airplane to a guy who operates a flight-seeing business in the eastern Caribbean. Again, the Jet A option is the only solution that fits his business.”
Okay, you say, so the Continental diesel engine burns less-expensive Jet A, but what does it cost to put it on a 172? “If you bring me your 172, the engine conversion itself is $90,000—but that varies by the U.S. dollar-to-Euro conversion rate—and you fly away with a new engine, FADEC and prop. All with a two-year manufacturers’ warranty,” Spengler explained. “If you want us to find you a good 172 airframe, you can figure that’s another $90,000 to $100,000, so a fully equipped Premier Edition 172 like our demonstrator is $298,000. Compare that to one of Cessna’s factory-new diesel-powered 172s at $435,000, and ours is a pretty attractive value.”
What A Difference The Diesel Makes
Because space is limited, and most everyone has flown Cessna’s legendary Lycoming-powered Skyhawk, I’m going to concentrate on what’s different about flying the diesel-in-the-nose Premier Edition 172.
While the preflight is pretty standard, there are a few differences, the first being when you switch on the master, before you reach for the flaps switch, check the condition of the aircraft’s battery. If it reads below 22.4 volts, then you need to hook it to a charger before you do anything else.
If for any reason charging isn’t an option—well, unless you can swap batteries—your flight is off for the day. Ground power starts aren’t an option with this airplane.
“That’s just a safety item,” explained Premier’s Chief Pilot Corbin Hallaran. “The reason is this is an electric airplane. Not the battery-powered kind, but all the major systems—especially the FADEC computers—are electric. While the FADEC does have a backup battery, it’s only got 30 minutes of power. Losing the alternator or ship’s battery power in this airplane is a must-land-now occurrence.”
The rest of the airframe preflight is standard. Make sure that when you sample the fuel that it’s not blue, but more the color of weak tea. Then, when you climb up on the wing to check the fuel levels, you’ll also notice the big “Jet A Only” placards, and the new fuel filler caps and inlets.
|From the G500 and GTN-750, to the Continental diesel, the Premier Edition 172 packs a lot of stuff in the panel and under the cowling.
“A regular 100LL filler nozzle will fit down in there, so you have to pay attention during fueling to avoid problems with mis-fueling. We have placards by the caps, but mistakes happen,” Hallaran said. “When I fly this airplane, I always supervise the refueling process. Not just to make sure they put the right fuel type in, but also that they don’t overfill the tanks. Jet A weighs more than Avgas, so the airplane is limited to 22.5 gallons on each side.”
Hallaran said that another difference is that the Continental diesel uses AeroShell 10W-40 diesel oil, which isn’t typically found at FBOs. Good idea to carry a quart or two with you.
Speaking of oil, while you’re looking over the three-bladed propeller, you’ll need a flashlight to look into a tiny opening under the right engine inlet to do a visual check of the engine gearbox oil. The Continental CD-series engines are geared, which means the engine turns higher RPMs than the propeller. It also means with the right gearing, the 135 hp engine can put out the equivalent “thrust” at the propeller as a 160 hp normally aspirated engine.
Light ‘Em Up
As you’ve no doubt heard, starting a diesel engine is push-button easy—literally. Switch on the master power, check some indicators, switch on the fuel pump, clear the prop, switch on the engine master and when the Glow Control Lamp goes out, push the start button. Hold it until you reach 500 RPM on the digital tachometer, and you’re done.
While we waited for the coolant and oil temperatures to get into the green, we got the Garmins ready to go. I have to say that this is my first hands-on with the GTN-750 touch screen, and it’s the best Garmin yet. The icons and intuitive operation make it a joy to use—and perfect for an infrequent flier.
After a few other checks, it’s time to release the breaks and push the power-lever forward to get rolling. Hallaran said that using Jet A isn’t the only “turbine-like” characteristic a pilot will find when transitioning to the Premier Edition 172.
“Like a turboprop or jet, you have to make all the power movements smoothly—no jamming the lever forward or back,” he said.
As I advanced the power lever to get rolling, I was again struck by just how quiet this engine is. With all the post-start checks we were doing, I really hadn’t noticed the lack of noise and vibration. But, when I pushed the power lever up to 50%, the lack of accompanying noise was a bit disconcerting at first. But, the acceleration away from the chocks proved all was well.
Taxiing was a pleasant, vibration-free ride to the run-up area. Once there, everything was pretty standard except the actual engine run-up. With this airplane, you pull the power to idle, and instead of fiddling with mag checks, power and mixtures, you just push and hold the FADEC button and watch the lights.
The dual FADEC computers will automatically self-test everything, including cycling the propeller at the proper RPMs. The final step is to advance the throttle to 100% power just to make sure she’ll deliver when you take the runway. The whole automated process probably didn’t take three minutes and it was done, and we were ready to go.
And We’re Off
With clearance from FXE’s tower, I rolled onto runway 08. Selecting 10 degrees of flaps and smoothly advancing the throttle to the stops, the two of us were airborne PDQ.
Hallaran said that best cruise/climb is 80 knots to help keep the engine cool while providing the best view over the nose. With a pretty big storm having just passed through the area, the air was unusually cool and smooth for a September morning in South Florida.
|Forty-five gallons of Jet A, please.
Once power and trim are set, she flies just like any Skyhawk—that’s to say, like it’s on rails. I hate to belabor the point, but this airplane is amazingly quiet and vibration free. In fact, I found myself repeatedly checking the tachometer to confirm we were indeed making power. We were. If you’ve ever gone on a long cross-country in a 172, you know how the noise and vibration can wear you out. I don’t see that being an issue with the Premier Edition 172.
Unfortunately, today wasn’t the time to test my theory. With the XM showing more nasty weather heading our way, my flight was to be short lived, and 4,500 feet was as high as we could go. That’s important to note because a diesel, like a turbine, likes altitude.
The higher you get, the better the fuel economy, which is one big reason to go diesel in the first place. For example, at 85% power, we saw 111 knots true at 6.3 gph. Pull back a bit to 75%, and we got 107 knots at 5.3 gph. Back a bit more to 65%, and we saw 100 knots at 4.6 gph. We went all the way to 45% power and held 52 knots at 3.4 gph.
Spengler said that on a recent trip home from Texas at 8,000 feet and 85% power, he averaged 117 knots true while burning 6.2 gph of Jet A. Nudge the power lever back to 75%, and with 44 gallons of Jet A in the wings, the Premier Edition 172 will outrange anybody’s bladder.
When it comes to air work, there are no surprises here. Steep turns, stalls, slow flight—all by the book. Hallaran said that the only addition a flight school or banner tower may make is to add the optional Micro Vortex Generators, which would improve low-speed controllability and reduce stall speed.
Is the Premier Edition 172 perfect? No airplane is. Aviation at every level is all about compromise. The fully equipped demonstrator I flew stickered at $289,000. Not cheap, yet it could be considered a bargain compared to the $435,000 price tag on a new diesel Skyhawk from the factory. At least until Premier gets FAA approval for the CD-155 engine, the biggest differentiators are that the factory version has additional 20 hp and a G1000 panel. Also, Premier will convert the Lycoming on your 172 to the Continental at a fraction of the cost of the new airplane.
But, no matter how you crunch the numbers, if you’re looking for an alternative to Avgas, I can tell you that once you get some left-seat time, you’ll agree that the Premier Edition 172 is as good as the Skyhawk gets.
Triple R Affordable Aircraft
|Throw a blanket over the panel and power lever, and you’d be hard-pressed to tell the Premier Edition 172 from a factory-fresh Skyhawk. And according to Premier’s Vice President of Operations, Art Spengler, that’s just the impression the company was going for when it committed to do the program.
“We looked around the industry to find a set of standards that matched our high-level of quality,” he said. “We had been following the efforts of the Triple R Affordable Aircraft group for the past couple of years and really like what they are trying to establish. Our Premier Edition 172 dovetailed nicely into their standards for a refurbished airplane.”
Tom Bliss, President, Triple R Affordable Aircraft, explains: “Our philosophy is to offer today’s buyer an airplane that has been basically rebuilt to an exacting set of parameters including all of the manufacturer’s inspections and upgrades,” explained. “Starting with a quality airframe, our goal is to give a Part 145 shop or custom rebuilder a set of pre-agreed upon guidelines to re-create an aircraft that is as close to new as you can possibly get.”
Bliss said that the Premier Edition 172 exemplifies what Triple R is trying to achieve. “Premier really fits our profile of a repair shop that is dedicated to delivering an exceptionally high level of quality and value,” he said. “The only thing that sets this apart from the new model 172s are the Garmin G500 avionics.”
“The point is, like any airplane refurbished to our standards, the Premier Edition 172 has been done with the highest degree of care, and Premier used the best available replacement parts and components,” Bliss said. “We are proud to have the Premier Edition 172 as an example of what buyers can expect a Triple R Affordable Aircraft to be.”