Born in 1909, Air Vice Marshal Harjinder Singh joined the Indian Air Force on its formation in 1932 as a technician. He served in the ranks till 1942 when he was granted a Commission in the Technical Branch. Since then, he has served in both Command and Staff appointments. He was appointed Officer Commanding, Base Repair Depot, in 1949 and Air Officer Commanding Maintenance Command, in 1955 when that Command was formed. The status of Maintenance Command was raised and A.V.M. Harjinder Singh was promoted in his present rank and appointed Air Officer Commanding-in-Chief, Maintenance Command.

In early 1960 it was decided to manufacture in the country a transport aircraft to replace Dakotas which were in short supply. After a decision by the Government to manufacture the AVRO-748 aircraft was taken, this task was given to A.V.M. Harjinder Singh who was asked to build the first aircraft as soon as possible and to set up a manufacturing line at the Base Repair Depot at Kanpur. This modern jet transport aircraft could only be manufactured with skilled and experienced personnel. An aircraft manufacturing depot was established alongside the Base Repair Depot at Kanpur under the Command of A.V.M. Harjinder Singh who was asked to undertake the manufacture of this aircraft. Jigs and tools were set up in the record time, mostly from available resources under the personal supervision of A.V.M. Harjinder Singh. Air Force personnel who have so far been accustomed exclusively to repair and overhaul work were trained in the factory methods and given the task of manufacture. With the assistance of a few specialists from England, the I.A.F. personnel numbering about 440 in all, built the first production model of the AVRO-748 in the aircraft manufacturing depot at Kanpur in a record time of 17 months when the production model was still being manufactured in the U.K. The Indian made AVRO-748 gave a flying display on 26th November 1961, when the Prime Minister blessed its maiden flight in Delhi.

The speed with which this aircraft was constructed by Air Force personnel with no previous manufacturing experience and with the resources which previously were mostly used for maintenance and repair and the quality of workmanship itself, which even the A.V. Roe of U.K. have acknowledged as something unique in aircraft industry, are a tribute to the tireless energy, skill and personal example of Air Vice Marshal Harjinder Singh. Air Vice Marshal Harjinder Singh has thus rendered distinguished service of the most exceptional order.