The third flight-test Gulfstream G600, T3, successfully completed its maiden flight on Friday. Registered N730GD, the fly-by-wire twinjet took off at 8:51 a.m. from Savannah-Hilton Head International Airport on a four-hour, 35-minute inaugural test flight. This milestone was reached just five months into the flight-test campaign for the G600.

“The consistent execution of the G600 flight-test program is directly correlated to our investments in research and development and is a testament to the rigor and discipline of our processes,” said Gulfstream president Mark Burns. “We look forward to our G600 entering service next year.”

In all, four flight-test aircraft and a production G600 will be used for the test program. “We increased the number of flight-test aircraft from three to four to maximize our efficiency in flight testing,” a company spokeswoman told AIN.

T1, which has logged more than 311 hours since its first flight on December 17, will be used to test brakes development, flying qualities, stall speeds, air data and RVSM; T2, which has 52 flight hours, will focus on loads, climb performance, flyover noise and function and reliability testing; T3 will be used for field performance, ice protection, cabin pressurization and oxygen system testing; and T4 will test automatic flight control systems, avionics and the fuel system. P1, the first production G600, will test cabin systems and the production interior.