Squadron Leader Hersern Singh Gill was one of the first pilots to be selected to fly a highly sophisticated aircraft introduced in the Indian Air Force. Since then, he has been actively connected with this aircraft either a Flight Commander or as a Staff Officer. He holds a Master Green instrument rating on the aircraft, and is an Instrument Rating Instructor. Due to his efforts, his Squadron attained 100% instrument rating and a very high operational state on the new type of aircraft. He was selected by Air Command to give a low level aerobatic demonstration on the aircraft on two occasions during the visits of foreign dignitaries.

Throughout, Squadron Leader Hersern Singh Gill displayed professional skill, leadership and devotion to duty.

During the operations against Pakistan in December, 1971, Wing Commander Hersern Singh Gill was commanding a Fighter Squadron in the Western sector. He led several operational missions on air defence, close support and counter air operations during the period 3rd December, 1971 to 13th December, 1971. He set an inspiring example to his pilots with his fearless approach, flying skill and dedication to his duties. His Squadron shot down one enemy F-104 aircraft over Jamnagar and hit another F-104 aircraft on 11th and 12th December 1971 respectively. Disregarding his personal safety and with great courage and skill, he undertook strie mission over the Badin Signals Unit Complex in the face of intense enemy Anti-Aircraft fire. On the 13th December 1971 he undertook another strike mission on the same target. During this attack his aircraft was shot down by the enemy Anti-Aircraft fire.

Throughout these operations, Wing Commander Hersern Singh Gill displayed gallantry, leadership and professional skill of a very high order.