Eastern jet with a western makeover

Our half-Cuban 8 tops out at 17,000 feet and we’re momentarily weightless as the nose comes down and I aim at an oval-shaped, central Florida lake while accelerating through 250 knots. None of these numbers make much sense because they’re so much bigger than those of the piston-powered aerobatic airplanes I normally fly. Even the fact that we just crested 17,000 feet is a stretch since we lifted off from Bradenton International Airport (SRQ) in Sarasota less than 10 minutes ago.

I half-roll, pull to level flight at 11,000 feet and 300 knots, and Hayes coaches me through another 4-G, over-the-top maneuver.

“You’ve got all this speed—so you might as well do something with it,” he quips.

This flight is a role-reversal for us that’s been a long time coming. Hayes and I met a couple decades ago in Atlanta when he was looking for tailwheel and aerobatic instruction in an American Champion Super Decathlon that he and two partners had recently purchased. Since then, he’s gone on to fly a dizzying variety of demanding airplanes including warbirds, aerobats, turboprops, and jets. Now, he’s introducing me to his one-of-a-kind L–39X, which combines a gorgeous, well-proven, Czech design with the best of the West. This aircraft manufactured by Aero Vodochody in Prague is now equipped with a Garrett TFE731 engine, Garmin avionics, and a complete systems overhaul performed by Code One in Rockford, Illinois.

The airframe modifications and engine installation in Illinois took one year to complete, and then the airplane flew to Gadsden, Alabama, where Jonathan McCormick spent four months repainting it. N395MK was awarded a Silver Wrench award at EAA AirVenture in 2021.

Hayes was among the first to put an Eastern Bloc jet thorough a stem-to-stern, warbird-style rebuild, and many other L–39s, Marchetti S.211s, and other former miliary jets are getting similar extreme makeovers.

The standard set by N395MK is less restoration than reinvention. Instead of bringing it to as-new standards, it’s now much better than it ever was. It’s more powerful, faster, more reliable, lighter, more efficient, and it provides situational awareness and automation that would have seemed like fantasy to its 1960s designers.

“The L–39 is already a great-looking airplane,” Hayes says. “My goal for this one was to preserve its authentic appearance while giving it great performance, high reliability, and modern safety tools that allow it to operate comfortably in the busy, complex airspace where I fly. I want to be able to fly it anywhere with confidence.”

In a bind

The airplane that would become N395MK entered the world at a tumultuous time. It was built in 1990 for the Soviet air force, but the Soviet Union was imploding at the time and the airplane was never delivered. It flew 11.5 test flight hours, then went into storage in Prague for seven years.

The airplane was imported to the United States in 1997 and logged more than 600 flight hours, mostly in Florida and Colorado, before Hayes bought it in 2019. He sent it to Code One in Rockford for a long list of upgrades. The biggest change there was the engine. Code One specializes in Garrett TFE731 installations that replace the original Ivchenko AI-25 with a more powerful, reliable, efficient, and serviceable engine that has a longer time between overhauls. The new engine also does away with the Russian requirement for an auxiliary power unit for starting, and removing it saves weight.

New oxygen and nitrogen systems were added along with an integrated Garmin avionics system that includes four G3Xs, two GTN 750s, and an active traffic warning system. Hayes also repositioned many of the internal switches for a more logical flow and added warning lights and sensors. Code One removed the wingtip fuel tanks and expanded internal fuel tanks, so the airplane now carries more total fuel (392 gallons, up from 340 gallons) with less drag. The airplane’s empty weight is also 575 pounds lighter. As a result of these changes, it can fly 400 KTAS at 25,000 feet while consuming about 145 gph at cruise compared to 360 KTAS at 175 gph with the Russian engine. The Garrett engine also responds to power changes instantly compared to the Russian engine which takes about 12 seconds to spool up from idle to full power. The Garrett puts out about 4,400 pounds of thrust, up from 3,800.

Nathan Jones started Code One 10 years ago after working as a mechanic and manager at Pride Aircraft and Draken. He said there are about 250 L–39s in the United States, and more than a dozen have had the Garrett engine upgrade. He expects the switch to Garretts to continue because the original Russian engines are increasingly costly and difficult to maintain. The largest overhaul facility for them is in Ukraine and its future is uncertain at best.

Code One started with five employees and has grown to 45. The company maintains a large stock of L–39 spare parts. Most of the Eastern Bloc jets in the United States were imported in the 1990s and early 2000s and fly under experimental/exhibition rules.

The Garrett engine conversion typically takes eight months and costs about $350,000, Jones said.

About 2,800 L–39s were built in the Czech Republic from 1970 until 1993. Most served as military trainers for Eastern Bloc air forces, and some were structurally beefed up and used for ground attack missions.

Getting insurance to fly an L–39 usually requires 1,000 hours of total flight time, an instrument rating, an L–39 type rating that takes about 12 hours of dual instruction, and at least 25 hours in make and model.

The airplanes have a service ceiling of 36,000 feet although, as a practical matter, their lack of reduced vertical separation minimum (RVSM) approval limits them to 28,000 feet. The L–39 pressurization system relies on pneumatic seals around the side-hinged canopies, and cabin altitude is about 10,000 feet at an altitude of 25,000 feet.

All L–39s were built with ejection seats, but those seats are difficult and costly to maintain, and about one-fourth of those flying in the United States currently have operational ejection seats.

Click on images to expand and view captions.

Aggressive maneuvering

Hayes completes his L–39 preflight inspection in the shade of his hangar at Sarasota while I strap into the slightly elevated rear cockpit. My backpack parachute is attached to the inactive ejection seat and a five-point harness latches me in tight. Hayes uses a robotic tug to pull the airplane outside, then climbs into the front seat via recessed steps in the fuselage. No ladders required.

Startup power is supplied by the aircraft battery and engine information is displayed on the G3X primary flight display/multifunction display at the center of the cockpit. Air conditioning keeps the cockpit cool despite the strong Florida sun.

Taxiing with the stick-mounted hand brake is the oddest part of any L-39 checkout. Use full rudder deflection and squeeze the brake handle a little for a small turn and a lot for a sharp turn. The nosewheel free casters so all turns require differential braking.

Hayes has taken most of the tower controllers at Sarasota flying, and they’re familiar with his routine. Once cleared for takeoff on Runway 32, he lines up with the centerline, holds the brakes, applies full engine power, gives the engine gauges a final check, then releases the hand brake.

The airplane weighs about 10,000 pounds at the start of our flight and the Garrett spits out about 4,000 pounds of thrust, so acceleration is brisk—like a lightly loaded Citation.

The rudder becomes effective at about 40 knots, and we reach the 90-knot rotation speed in about eight seconds and lift off at 95 knots after a 1,500-foot ground roll. Hayes raises the landing gear right away, then holds a shallow, 5-degree climb as the airplane accelerates through 140 knots and he raises the flaps. The airplane seems to come into its own as it reaches its best-climb speed of 215 knots, and we turn northeast and climb at 3,800 feet per minute up to 11,500 feet.

At 92 percent N1 the airplane reaches 270 KIAS in level flight. Visibility is outstanding, and pitch and roll forces are well balanced with moderate breakout forces. In hard turns the G onset is rapid and sustained, and the airplane barely decelerates at all. The stick pull force is moderate at first but gets lighter as G forces increase. At 4.5 Gs, the stick seems to want to move back into my lap on its own.

After a series of horizontal maneuvers—aileron rolls, point rolls, barrel rolls—we move on to over-the-top figures. Loop, half-Cuban, Immelmann. Each begins at a minimum 300 KIAS and a power setting of 95 percent N1, and the airplane keeps its energy. Our main concern is inadvertently exceeding 18,000 feet and entering Class A airspace without an IFR clearance. It’s a vigorous workout.

Descending into Sarasota, Hayes asks for and gets an overhead approach and initiates it over Runway 32 at 200 KIAS. It starts at 70 percent power and 200 KIAS in level flight followed by a hard 180-degree turn to the downwind. Deploying the belly-mounted speed brakes slows the airplane to 180 KIAS, and lowering the landing gear reduces airspeed at 160 KIAS. Approach flaps slow the airplane to 145 KIAS, and Hayes starts a 180-degree descending turn to final and adds landing flaps. He adjusts pitch and power with a target of 120 knots on a one-mile final. The engine is set to about 70 percent N1 as he follows the PAPI lights and then pulls the power lever to idle over the runway threshold.

We touch down on the fixed-distance marker at about 90 knots and the trailing-link landing gear makes it a soft return. Once the nosewheel touches down, a weight-on-wheels sensor makes the hand brake effective again, and light braking allows us to exit at a mid-field turnoff on the 9,500-foot runway.

A modern warbird

After years of museum-quality restorations on World War II-era piston aircraft, the stage has been set for these mostly Eastern Bloc jets to get new leases on life. They’ve always had impressive performance. Now, modern engines, digital avionics, and detail-oriented Western craftsmanship are making them highly reliable and maintainable.

N395MK was one of the first L–39s to get such a painstaking reinvention. It won’t be the last. 

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