Gulfstream G700 T4 Enters Test Fleet N705GD joined the G700 flight test program on Friday when it took the the air for the first for an hour and fifty-six minute flight. This G700 is dubbed T4 by Gulfstream which showcases how this new program is already advancing and maturing. Two more test articles are to join the flight test team. T5 and T6 are the remaining aircraft. T5 will be utilized for Level D simulator data gathering as well as avionics data while T6 will be the production test aircraft with the finished interior for testing.