For more than a century of powered flight, engine technology has been the main key to improving aircraft performance. And so it is with Aircraft Industries’ latest version of the venerable L410. It is fitted with 800 shp GE Aviation Czech H80 powerplants and was just certified in April 2013. It has only 50 shp more per side than the previous version, but it offers much improved hot-and-high airport and climb performance, faster cruise speeds on warm days and at least five percent better fuel efficiency.
Operators of the GE-powered L410 also will benefit from a TBO increase from 3,000 to 3,600 hours, no fuel injector nozzle maintenance and no midlife hot section inspection. The water injection system also has been eliminated. The H80 shares its type certification with the 1990 Walter M601E, but dissassemble the engine and profound internal changes are apparent. The two-stage axial and single-stage centrifugal compressor take full advantage of GE aerodynamic expertise to raise the compression ratio, and improved metal alloys boost temperature margins.
GE bought Walter in 2008, moved the plant to a factory next door to Kbely Airfield and completely revamped the production process.
Friday before the Paris air show, we strapped into the left seat of a GE-powered L410UVP-E20 at Kunovice, Czech Republic, accompanied by factory test pilot Petr Jarocky, for a first hand, albeit brief, demonstration of its improved performance. UVP is the Russian equivalent of STOL (short takeoff and landing) in English. The UVP has increased wingspan and a taller tail that enable it to use the increased horsepower of the twin H80 engines to full advantage.
The -E20 designation indicates that it is certified to EASA CS23 commuter category standards. Similarly, the L420 is an -E20 certified to FAR Part 23 commuter category standards. The GE powered version, equipped with five-blade Avia AV 725 props, was certified in April 2013.
Basic Operating Weight was 10,390 lb with the two of us in the cockpit and a full array of flight test equipment bolted into the main cabin. Two flight test engineers, plus all their kit, added 440 lb. Loaded with 1,763 lb of fuel, computed takeoff weight was 12,595 lb, about 87% of MTOW.
Airport elevation was 581 ft, OAT was 17C and QNH was 1023 Mb. At that field elevation, the full 800 hp takeoff rating was available to 33C and up to 40C for one engine inoperative conditions. Balanced field length is not published in the AFM, thus it’s necessary to compute accelerate-stop and accelerate-go performance, plus V-speeds, using more than a dozen charts. This airplane begs to have a software app for your iPad or laptop that would automatically compute airport performance.
With 6,600 ft of concrete available, runway length wasn’t a limitation, so we used simplified speed computations for flaps 18 degrees: 78 KIAS for V1 takeoff decision speed, 81 KIAS for rotation and 100 KIAS for the V2 OEI takeoff safety speed. OEI climb gradient was 4.9%.
L410’s cockpit is a blend of traditional and modern features, having left and right side Universal Avionics PFDs, an optional Honeywell KFC325 autopilot, TCAS and E EGPS, plus a plethora of analog gauges in the instrument panel, more than a dozen circuit breaker toggle switches in the overhead panel and some Czech and/or Russian design oddities. For example, there is an electrically controlled and hydraulically actuated ground spoiler system that’s activated by a guarded switch on the left hand control wheel, a nosewheel steering tiller lever on the control yoke stalk and a low-speed, roll control assist system that is activated in the event of an engine failure on takeoff.