Gulfstream Aerospace’s flight-test campaign for its G500 program has surpassed more than 100 hours over more than 45 missions. The milestone comes exactly one year since the large-cabin twinjet, as well as its larger and longer-range G600 sibling, were launched at the company’s headquarters in Savannah, Ga.

In the five months since its maiden flight, the first flight-test G500 (T1) has reached an altitude of 38,500 feet and a maximum airspeed of Mach 0.80. Its longest flight to date is five hours and 22 minutes, Gulfstream said.

“This airplane has been flying exactly as expected,” said Gulfstream senior vice president of programs, engineering and test Dan Nale. “The team recently flew three missions in one day, with hot refueling between flights, for a total flight time of nearly seven hours. Our test pilots have said the aircraft’s handling qualities are exceptional.”

Gulfstream has completed initial testing of the aircraft’s handling qualities, as well as testing of the high-speed and attitude recovery stall system. T1 is currently involved in flutter and envelope expansion testing. Meanwhile, the company is preparing T2 and T3 for flight, with the start of ground and loads testing on T2 and avionics testing on T3.

The fourth flight-test G500, T4, will come online next year and focus on human factors and supporting systems. This airplane will also be used for functionality and reliability testing.

Fatigue testing will begin once structural testing is complete. The fatigue test article has already been manufactured and will be subject to three lifetimes of operation to evaluate the structural integrity of the aircraft, according to Gulfstream.

Together, the G500 and G600 programs have accomplished more than 39,000 hours of lab testing. Gulfstream expects FAA certification of the G500 in 2017 and entry into service in 2018; the G600 is planned to follow by one year.