I have been tracking this flight for the past week or so…Any thoughts as to why it would have circled at 4000 feet after taking off?
Because of a criminally obsolete air traffic control system that can allow an airplane to leave the ground and receive holding instructions seconds after takeoff due to traffic at the planned destination airport.
While this is probably right for this particular flight, there are SIDs that require a climb in a holding pattern; the CATHEDRAL8 out of KPSP or the FMG7 and HUNGRY2 departures out of KRNO require a climb in their respective holding patterns until you are at or above the MEA for the direction of flight you’re going to.
BL.
What you describe is for the purpose of meeting a climb gradient until clear of terrain/obstacles. Not an issue out of KPIT.