In May 1958, Singh was promoted to the rank of Air Vice Marshal and continued as the head of the Operational Command. The appointment was upgraded to Air Officer Commanding-in-Chief (AOC-in-C) Operational Command. He led the Operational Command until November 1959, handing over command to Air Vice Marshal Erlic Pinto. Singh has the distinction of being the longest serving head of the Operational Command. He led the Command for a total of six years in two stints - December 1950 to December 1952 and December 1955 to November 1959.