Figure: G450 Twin Engine Go-Around, from G450 Aircraft Operating Manual, Rev 24, §06-05-00, figure 6.
The G450 manuals no longer mention balked landings, other than to say that if you have one don't forget to turn the ground spoilers off. The older manuals do cover the procedure and they are worth considering because so much can go so wrong when a landing is balked.
During my 20 years in the Air Force we had several examples where a balked landing went horribly wrong. The best example, however, was civilian: Mishaps / Learjet 60 N999LJ. Once you've made the decision to balk the landing, you should stick with it. Indecision has killed.
The current Aircraft Operating Manual go around procedure is fine but it leaves out one important point. Once you have weight on wheels the autothrottles disengage and cannot be convinced to do anything else. (They are not indecisive.) Not even the TO/GA button will change their mind-set. You have to disengage the autothrottles and push them forward. Once airborne you can reengage them.
What follows are quotes from the references listed below, with my comments and techniques shown in blue.
Gulfstream no longer specifies a balked landing procedure but here is what the AOM used to say:
[G450 Aircraft Operating Manual, Rev 24, §06-05-20, ¶1.A.] When it becomes doubtful that a safe landing can be accomplished, apply go-around power and simultaneously increase pitch attitude (15°) to stop the sink rate as quickly as possible. Do not change aircraft configuration until sink rate is arrested and the aircraft will not touch down. Contact with the runway may be unavoidable. If the aircraft does touch down, allow the aircraft to accelerate and continue with the go-around. Once a positive rate of climb is achieved, set flaps to 20° and retract the landing gear. Climb out at VREF+5 knots until a safe altitude is attained.
NOTE: In the event that a go-around is performed because of a balked landing (after touchdown on runway), select ground spoilers (GND SPLR switch) to OFF.
[G450 Aircraft Operating Manual, §2B-12-40 ¶5.] The retard mode is used to establish a fixed rate of throttle retardation to the idle thrust position during the aircraft flare on landing. The retard mode is used for AP/FD coupled and non-coupled approaches, and it is activated based on radio altitude < 50 ft (i.e., gears down, flaps > 31.5°).
When the aircraft touches down, and both throttle levers are located in the idle thrust stop, the AT automatically disconnects in preparation for reverse thrust. If the aircraft touches down without the AT retarding the throttles because of a failure to detect a landing configuration or lack of radio altitude, the AT retards the throttles to the idle thrust position when touchdown is detected (i.e.,WOW or both wheels spun up), before it automatically disconnects. The AT remains engaged until touchdown, so it is available in the event of a go-around during the flare.
Gulfstream G450 Aircraft Operating Manual (Historical), Revision 24, September 18, 2009.
Gulfstream G450 Aircraft Operating Manual, Revision 35, April 30, 2013.