Snecma has confirmed the 11,000-lb-class Silvercrest turbofan has been flying since May on a modified Gulfstream II, after several delays. As another seven Silvercrests are running on the ground, the France-based engine manufacturer is still targeting late 2015 for certification. The first two applications are the large-cabin, long-range Dassault Falcon 5X and the super-midsize Cessna Citation Longitude, both twinjets.

“We have opened the flight envelope for the modified Gulfstream II with one Silvercrest and one Rolls-Royce Spey,” Eric Portejoie, the program's new general manager, told AIN. The aircraft flew at up to Mach 0.82 and 40,000 feet. Over the May-June period, it totaled “fewer than 10 flights, lasting three to four hours each,” Portejoie said. This was for the first phase.

Last summer, further modifications were performed to enable in-flight restarts with an electric system rather than the Spey’s pneumatic starter. Flight-testing was to resume in late September, also including operability power management and trials. Some 250 hours are planned for the entire flight-test program. The modification was performed by Texas-based Sky Aerospace Technology (in the same group as Sierra Industries).

Ground tests have already involved hail and bird ingestion, the latter having been performed only on the fan and associated booster.

Dassault received its first two Silvercrests in June. The assembly line is up and running at the Villaroche factory, near Paris; use of the test bench for production engines was validated last summer. Snecma is responsible for the integrated powerplant system, including the nacelle, thrust reversers and mounting systems. Podding activities have begun at Aircelle’s facilities in Toulouse.

Compared to existing engines in this class, Snecma targets a 15-percent cut in fuel burn, a 50-percent margin below the CAEP6 NOx emission standard and a noise level 20 EPNdB below Stage 4. The engine is to provide 11,450 pounds of thrust (at sea level, ISA+20) for the Falcon 5X. With an 11,000-pound thrust rating, it is to equip the Cessna Longitude–which will involve minor changes, such as the accessory gearbox’s design.

The schedule is still fluid on the latter program. Last May, a Cessna official said the Longitude is still in the early design stage, as the Wichita-based company continues to solicit customer input on the design. “We are in standby mode and will start again as soon as Cessna issues a new schedule,” Portejoie said.

Customer-support plans are being devised around three hubs to be located in Europe, the U.S. and Asia. Each hub will feature a warehouse for spares parts, a hotline and a go-team. Snecma is also betting on advanced health monitoring to ensure top-level engine reliability. o