Gulfstream V / G500 / G550
Flight Crew Air Transport Pilot (ATP)
Workload; Situational Awareness
Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter CFTT / CFIT
Flight Crew Became Reoriented
Human Factors; Procedure
This event occurred while flying the ILS 6 / Circle to Land 1 approach at TEB. It was nighttime and the weather was VMC; winds were 320/18G33 with light to moderate turbulence reported on approach. Prior to circling; tower reported the traffic we were following and instructed us to square our turns to final (to increase our spacing). I initiated our circle; turning to the right approximately 60 degrees (more than would normally be required for the circle). As we descended and began to turn back to final; we received an Obstacle Alert from the aircraft warning system. I began to raise the nose and the alert ceased after just a few seconds. I completed the turn to final and we landed.Suggestions: More adequate spacing between us and the preceding aircraft would have negated the tower's instructions for us to alter our planned circling path. I believe by lengthening the circling path and the amount of turn required; the expected geometry changed. This added to the workload; making glide path management more difficult. Or we could have continued to fly the planned circling path and executed a go-around if inadequate spacing developed.
[Report narrative contained no additional information].
G550 flight crew reported receiving an obstacle alert from the GPWS on a night visual circling approach to TEB.