The plane carrying Nigeria international
Passengers were hurried off the aircraft by the crew as a safety precaution, after a fault occurred with the air conditioning system in the cabin of the Carpatair flight.
Fire engines and an ambulance were placed on standby at the scene after the plane had been fully evacuated.
Iheanancho along with all passengers - which included media personnel, who began to provide updates via Twitter - were escorted back to the terminal at Manchester Airport after safely disembarking.
They later re-boarded the aircraft after it was cleared for take-off.
"After reports of an air conditioning fault, passengers on the Carpatair charter flight to Bucharest were disembarked back to the terminal as a precaution," a statement from Manchester Airport read.
City are travelling to Romania for the first leg of their play-off tie against Steaua, which takes place on Tuesday.
The forward is set to play in his first Champions League game for Pep Guardiola. He was introduced in the latter stages of their 2-1 win over Sunderland in the Premier League.