Grand Renaissance Commander Levels Up the Twin Turboprop

Grand Renaissance Commander

Kevin McCullough's grandfather, who started a Commander service center called Aero Air in 1956, used to say: “God never made a low-wing bird.” So when McCullough was old enough to start flying, there wasn’t much choice.

“I learned to fly in a Lark Commander, got my multiengine rating in a Shrike Commander and then went up to Turbo Commanders and have flown almost every type of Commander that was made,” he said.

McCullough has accumulated more than 5,000 hours flying Commanders, and his life is deeply involved in the Commander family of airplanes. Together with Jack Erickson of Erickson Air-Crane, McCullough owns and operates Aero Air, a Twin Commander service center as well as a busy Commander operator. The company has expanded its mission, but the core of the business still lays with Commanders, using them for medical evacuation, fire spotting and charter services.

When McCullough flies personal trips, his first choice is his 690B Commander. “It takes 29 minutes to get to Sunriver,” he said, referring to a 120 nm trip he takes regularly from his base at Portland-Hillsboro Airport (HIO) to Sunriver, where he has a second home.

The Aero Commander 690B is a pressurized high-wing twin turboprop with a rugged design, simple systems and plenty of power. With a roomy cabin featuring seating for up to seven people, including the pilot, the airplane appears to have been designed with both the flying and non-flying occupants in mind: great comfort and visibility, good performance capabilities and nice handling characteristics. Its rugged construction also is well suited for unimproved airport operations. It is no wonder the 690B has become one of the most popular Commanders produced to date.

Long Legacy
Ted Smith, a former Donald Douglas engineer, conceived the idea of what was initially called the Aero Commander. Smith's goal was to come up with an airplane design optimized to carry people to and from destinations the commercial airlines didn't serve. Together with an engineering team, Smith designed and flew the first Aero Commander and was able to secure private funding for the final development and initial production of the airplane. The company that ensued was called Aero Design and Engineering Company.

In 1950, four years after Smith put his ideas on paper, the Aero Commander 500S, also called Model 520 and later the Shrike Commander, received its certification paperwork from the Civil Aeronautics Administration—the predecessor to the FAA.

To prove the extraordinary single-engine performance and stability of the new airplane, Aero Design and Engineering Company organized a marketing demonstration flight from its base in Oklahoma City to Washington, D.C., in May 1951. But this was no ordinary demo. The airplane was fully loaded, and only one engine was operational. The propeller was even removed from one side.

The flight went off without a hitch, and the Aero Commander became a hit. It was even considered safe enough to become the first twin-engine Air Force One—used in the late 1950s by President Eisenhower. Later, the Shrike Commander was also made famous by Bob Hoover’s mind-blowing aerobatics routine.

Several other piston Commander models followed, and in the early 1960s, after Rockwell acquired the company, the 680FL Grand Commander was introduced. It featured a much longer fuselage and the trademark picture window under the wing. The same fuselage was used for the 680T, the first Turbo Commander, which sported two 575 hp Garrett AiResearch TPE331-43 engines (the production of which was later taken over by Honeywell Aerospace), providing higher gross weight capabilities and better performance. The 690 followed in 1973 with a 717.5 hp TPE331-5, a larger wing, rudder and dorsal fin, and a longer tail cone. The result was an airplane with a service ceiling of 31,000 feet, a 9,600-pound gross weight and a baggage capacity of 600 pounds. And with subsequent 690 models the performance numbers improved even more.

As is the case with many legacy airplane manufacturers, there is much confusion about the model names. This holds true in the case of the Commanders. As the 690 series continued to improve, it morphed into the 840 (690C), 980 (695), 900 (690D) and 1,000 (695A/B)—four models that also bear the name Jetprop. These new model numbers were “marketing model numbers that I believe were loosely tied to the thermodynamic horsepower available for the different engine models,” explained Geoffrey Pence, technical service manager at Twin Commander, who has worked on Commanders since 1973.

In 1981 Gulfstream acquired Rockwell and took over the Commander production. But the acquisition was the deathblow for the Commander production line as Gulfstream decided to zero in on business jets. After Gulfstream supported the Commander fleet for a few years, the type certificate and 58,000 pieces of production tooling were sold and have since traded owners several times. Since 2008, Twin Commander Aircraft is based in Creedmoor, North Carolina, and is a subsidiary of Firstmark Corporation—a company that specializes in the support of legacy aircraft. With 18 employees, Twin Commander provides technical, engineering and parts support.

And this type of support keeps the aging Commander fleet in the air. With about 1,000 Turbo Commanders built, about 750 are still flying, according to Matt Isley, president of Twin Commander Aircraft. The Twin Commander service centers are even capable of offering a full refurbishment program—the Grand Renaissance—to bring the airplanes back to tip-top shape. More on that later.

Rugged Simplicity
Looking at the Commander fuselage, its shape is nearly square. This shape provides a lot of space in the cabin, and the good news is that you don't need to worry about filling it up. The 690 has a useful load of 4,180 pounds and a fuel capacity of 389 pounds, so the payload is well over 1,500 pounds, enough to fill all the seats and bring lots of luggage.

And speaking of luggage, the 224-square-foot baggage compartment, which has a weight capacity of 600 pounds, provides plenty of space for luggage, golf bags and skis (at least the new, shorter shaped skis). Randy Dunn, founder, owner and winemaker at Dunn Vineyards in Angwin, California, has owned Commanders for well over a decade and regularly flies to the Baja Peninsula in his Commander 690A. He recalls unloading the airplane at his destination one time and being unable to fit the luggage he and his wife brought into the truck that picked them up at the airport.

Dunn frequently lands on dirt strips and believes that “this plane is made for that kind of mission.” The propellers are high off the ground, and the landing gear is beefy and very strong.

The landing gear system is pneumatic, hydraulic and gravity. That might sound complex, but “it’s a very, very simple system,” McCullough said. If the hydraulic gear extension fails, the gear simply drops out by gravity, and once it’s extended a set of bungees holds it in place.

The fuel system is simple too. The fuel tanks feed into one sump, so there’s no fuel management required.

"You just fill it up and burn it," said McCullough. And at 300 knots TAS, he says you can expect to burn about 70 to 75 gallons per hour in cruise.

Two Honeywell TPE331 engines convert that fuel to power. The TPE331 is a direct-drive turboprop engine with a track record of high reliability. More than 13,000 of these engines have been delivered to date, and they have accumulated more than 116 million hours of flight time. The Turbo Commander 690 was originally designed with the 717.5-horsepower TPE331-5 engines, which provide a cruise speed right around 270 knots. But the engines can be upgraded to the Dash 10T, which together with the wide-chord Hartzell propeller brings the cruise speed up around 300 knots. Both the Dash 5 and Dash 10T provide good longevity, with a 5,400-hour TBO.

Grand Renaissance
Grand Renaissance is a transformation of the airplane into a like-new Commander, the only difference being that the time on the airframe remains. Only three of the domestic and one international service centers are capable of completing a Renaissance project, which according to McCullough takes about six to nine months to complete. Any Twin Commander can go through the Grand Renaissance program, but generally only Turbo Commander customers will put their airplanes through the program.

McCullough said the manual for the project is about four inches thick, so the upgrades and replacements are too numerous to list. Suffice it to say that the airplane is completely gutted, and the airframe and all the systems undergo a full refurbishment in which many components are replaced.

And once all the pieces of the puzzle are brought together, a custom paint job and interior installation are completed. Final inspections are done by a representative from Twin Commander Aircraft. After a new dataplate is put on and the airplane emerges from the service center, “it’s no longer a Twin Commander, it’s a Grand Renaissance Commander,” said Isley.

Bruce Byerly, vice president of Naples Jet Center and a longtime Commander salesman, says the resale value for Grand Renaissance airplanes remains higher than that of comparable new airplanes when they enter the used market, but Renaissance owners tend to hold onto their airplanes.

“We haven’t seen one done in the past five years that was put back in the resale market,” Byerly said.

However, the service centers assist potential customers in finding airplanes that they can take through the Grand Renaissance program. You can pick up a decent 690A or B for around $450,000 with the -5 engines or an upgraded model for just under $1 million, and “typically between 25 to 40 airplanes are available on the market,” explained Byerly.

"If you're going to do a Renaissance, it's also a good time to do the panel," said Byerly. And most Renaissance customers do. Lately, customers tend to choose Garmin's G500 or G600 screens in combination with a GNS 430/530 (which now will be replaced with the GTN 650/750). Byerly said Eagle Creek, Naples Jet Center's affiliate in Indianapolis, Indiana, is working on an STC for Garmin's G950 glass cockpit.

When it’s all said and done, if the customer decides to include new avionics and the Dash 10T engine upgrade, the cost for a Grand Renaissance project can be more than $2 million, but it all depends on the history of the airplane and the current cost of the engine and avionics. Isely said 41 Grand Renaissance projects have been completed since the program began in the mid-’90s.

The benefit of the Grand Renaissance program extends to other Commander customers.

“It really keeps the parts movement active and keeps the airplanes flying,” said Byerly. And parts availability for this legacy airplane does not seem to be a problem. “Ninety-five percent of everything we sell for Commanders gets shipped out the door the same day,” said Isely.

On a beautiful summer day in Hillsboro, Oregon, I stepped into N71AA, one of Aero Air's 690Bs with the Dash 10T conversion. Entering the airplane was easier than getting into my car. The bottom of the fuselage is close to the ground, and Aero Air created an STC that removes the short airstair and allows the door to be opened all the way, flush with the fuselage, which provides significantly more space in the doorway. This is particularly helpful for operators, such as Aero Air, that use the airplane for medical transport.

The flat floor also makes it easy to move around the cabin. But, as often is the case with this class of airplane, climbing into the seats in the cockpit is not the easiest feat, because there is not much space between the seats and the center column.

But once I had strapped myself in I was impressed with the comfort and visibility. The Commander has a large, heated, wrap-around windshield and a skylight above each side window, providing terrific forward and side visibility as well as natural light in the cockpit.

McCullough explained that the direct-drive engines give the Commander 690B a propensity for hot starts, but as long as you watch the EGTs on start-up and shut the engine down at the first sign of a potential hot start, there is nothing to worry about. We got both engines started without a hitch.

Another potential gotcha is steering the Commander. Unlike many nose-wheel-equipped airplanes, there is no mechanical link between the rudder pedals and the nose gear. Instead, the steering is hydraulically actuated through the first part of the toe brakes, which activates a cylinder that turns the nose gear. Press the toe brakes further and the brakes on the main wheels are activated. The system allows the pilot to apply full rudder in one direction while applying steering in the other, which (while there is no good reason to do it) is quite unique. I agree that steering was a little tricky at first, but it didn’t take me long to get the hang of it, and I taxied the airplane smoothly toward Runway 31 at Portland-Hillsboro Airport (KHIO).

With an airplane coming in on final, we made a rolling takeoff, and while I pushed the throttles slowly, the power they responded with was remarkable. We got off the ground in no time and used a fraction of the 6,600-foot runway. McCullough claims he has landed and taken off with 71AA on a 1,900-foot airstrip, though he doesn’t recommend it for inexperienced Commander pilots.

We weren’t anywhere near gross weight with only three people on board, three-quarters worth of fuel in the tanks and no luggage, but the 4,000 fpm climb rate at 130 knots was still impressive. Satisfied with seeing that kind of performance capability, we pushed the nose over, and even at 160 knots we were pushing 3,000 fpm.

In addition to providing great climb performance, the Dash 10T engines reduce the performance issues associated with an engine failure. McCullough said it “climbs 1,000 fpm on one engine at gross weight.” And with the large rudder surface, asymmetrical thrust is easy to control. You can even trim the airplane out and put your feet on the floor. Several people I spoke with about the Twin Commander said an engine failure is a “non-event.” We didn’t kill an engine completely, but pulled the throttle back on the right one, and I felt that it was easy to control the airplane.

We did some stalls, and McCullough explained that the long, thick wing helps make the stall speed and Vmc within two knots of each other.

“If I lose an engine, I can maintain directional control of the airplane right to the stall,” he said.

With a clean configuration, the buffet came at 75 knots and with flaps 72 knots. I felt no tendency for either wing to drop.

I also played around with steep turns and got a good feel for the large control surfaces. I lost some altitude on my first attempt, but the second one was right on the mark. Despite being a heavy airplane, the 690B is fun and easy to hand-fly.

Although my preferred seat in an airplane is always up front, I unbuckled my seatbelt to check out the passenger experience. It was impressive. The interior was equally as nice as any airplane rolling off a factory floor, and there was plenty of legroom. But the most impressive thing was the massive picture windows in the rear, which provide the passengers with a view that nearly equals the pilot’s.

Returning for the landing, we were cleared for the shorter Runway 2. Through clear skies, I was looking right at Mount Rainier on final, approaching at 110 knots. As I got closer, I slowed to 95 knots over the fence and managed to finish the flight with a decent landing.

I have to admit that I always thought the Commanders looked a little strange. But after having a chance to fly a Turbo Commander, I now understand why the passion for these airplanes runs deep with those who fly them.

“It’s one of the cool things about Commanders — they’ve got kind of like a cult following,” said Byerly.

And it’s the same for those who work on these airplanes. Isely said some employees at the 18 Twin Commander service centers have been working on Commanders for more than 50 years, and the total amount of Commander experience for the employees adds up to more than 1,000 years.

Commanders might have been out of production for decades, but with hundreds still flying regularly and with strong support from Twin Commander, these airplanes should continue to fly for decades to come.

Pia Bergqvist joined FLYING in December 2010. A passionate aviator, Pia started flying in 1999 and quickly obtained her single- and multi-engine commercial, instrument and instructor ratings. After a decade of working in general aviation, Pia has accumulated almost 3,000 hours of flight time in nearly 40 different types of aircraft.

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