Sikorsky is to start certification testing on the S-434 light single helicopter in January, thus postponing FAA certification to a targeted December 2011, AIN has learned. With this improved Schweizer 333, engineers already have completed some 50 hours of development flight tests to “mitigate risks and develop new systems,” according to company spokesperson. Engineers are now conforming two aircraft for 75 to 100 hours of certification flight tests. On the S-434, a four-blade main rotor provides “substantial performance improvements and handling characteristics over a S-333 at a comparable gross weight,” according to Sikorsky. Mtow thus increases by 300 pounds, to 2,850 pounds. The new tail of the S-434 rotor can generate more than 20 percent additional thrust, which is said to improve yaw handling and controllability. Sikorsky claims to have three civil orders for the S-434. In the defense sector, the Saudi Ministry of Interior has already taken delivery of nine copies of the new aircraft.