Sikorsky has completed initial main transmission and drive train testing of the S-92 Helibus ground test vehicle, clearing the way for the inaugural first flight of the new medium-size helicopter by the end of December and an anticipated production decision in 1999.

The manufacturer has completed around 200h of testing on a static prototype at its West Palm Beach development flight centre since the first blade-off transmission run on 14 August.

Blade-on testing of the drive train and transmission has been under way since early September, including over torque and endurance runs, and will continue after the first flight.

Sikorsky has just completed delivery of the second S-92 prototype, the first actual flight test aircraft, to West Palm Beach. The first flight had originally been scheduled for September, but this has slipped some three months. "It will happen this year, we 're looking at the the third or fourth week of December," says S-92 programme manager Frederick Geier.

Around 350h of flight testing has been scheduled for the prototype, including an initial 120-140h of system "shake-down testing." The second General Electric CT7-6D turboshaft-powered test helicopter will also be involved in handling and avionic development testing, including the S-92's automatic flight control system.

The third prototype will undertake another 450h of flight testing, focused mainly on the improved production standard CT7-8 turboshaft, full authority digital engine control and auxiliary equipment such as flotation gear.

This process will carry over to the fourth prototype's 500h flight test programme.

An additional 200h of acoustic, vibration, and external loading testing has been set aside for the fifth and final prototype to be configured for the utility role.

The S-92IU will feature open cabin access to the rear-loading ramp and side-seating for up to 22 passengers. The civil S-92C is designed to seat 19 passengers and will incorporate a rear cabin/ramp partition.

Sikorsky is now targeting to complete full US Federal Aviation Administration and European Joint Airworthiness Authorities FAR/JAR 29 certification by mid-2001.

First deliveries are provisionally scheduled for later that same year, provided that the programme receives a production go-ahead from Sikorsky chief executive Eugene Buckley.

"As long as we make a decision by mid-1999, we can meet all the production assessments we have right now," says Geier. "We're responding to questions on performance and availability and we're talking to several customers-but cannot accept any contracts until after the first flight," he adds.

Source: Flight International