Safran Silvercrest To Have Two Takeoff Thrust Ratings

 - June 26, 2017, 10:56 AM
Safran's Silvercrest engine will have two different takeoff thrust ratings—one for normal operations and another for hot-and-high conditions. The latter can be used in “certain high ambient temperature conditions" and is limited to a maximum accumulated usage of 20 minutes in any one flight. (Photo: Safran Aircraft Engines)

Safran Aircraft Engines’ Silvercrest 2D and 2C turbofans, which will power the Dassault Falcon 5X and Cessna Citation Hemisphere, respectively, will have two different takeoff thrust ratings—one for normal operations and another for hot-and-high conditions—according to proposed special conditions published today in the Federal Register.

The first rating corresponds with the rated takeoff thrust of the engine—11,450 pounds for the 2D variant and 12,000 pounds for the 2C. Meanwhile, the second takeoff rating maintains the takeoff thrust in “certain high ambient temperature conditions.”

Use of the ‘‘Rated Takeoff Thrust at High Ambient Temperature’’ (Rated TOTHAT) is limited to two periods of no longer than 10 minutes each under one-engine-out conditions or five minutes each under all-engines-operating (AEO) conditions in any one flight, for a maximum accumulated usage of 20 minutes in any one flight. Each flight where the Rated TOTHAT is used must be followed by inspections and maintenance actions.

The special conditions also require additional test cycles that include at least 150 hours of engine operation to demonstrate the engine is capable of performing the Rated TOTHAT rating during AEO conditions without disassembly or modification.

According to the document, the Silvercrest is slated to receive FAA certification in August next year, just one month before Safran's extended type certification application expires. EASA certification is expected in spring 2018.