As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, A LOUD NOISE WAS HEARD IN THE COCKPIT. INSPECTION REVEALED THE CANOPY ASSIST SPRING (EASES OPENING OF CANOPY - 1 INSTALLED EACH SIDE) HAD BROKEN. FLIGHT RETURNED TO BASE WITH NO FURTHER INCIDENT. THIS WAS THIRD TIME ON 2 AIRCRAFT.