M/s Hybrid Aviation Diamond DA-42 aircraft (Reg. No. AP-BMR) got airborne at around 1045 LT from RWY 14 of Walton Airport. Aircraft leveled off at 1500ft IND, with throttle at 45% power setting and 120 kts IAS at right downwind for RWY 14. Pilot contacted Lahore Approach for practicing VOR let down and was told to standby. At the end of downwind pilot observed door open red light “ON” on the Primary Flight Display (PFD) followed by the audible warning sound. Pilot observed the door latch in halfway position between lock and unlock. Pilot brought the throttle to 35 % power, and reduced speed, as soon as pilot looked back at the very instance the rear canopy flew off. After a controllability check, the aircraft made normal landing, however did not inform ATC about emergency during or after the flight.
