As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE CLIMBING THROUGH 700 FT, A LOAD NOISE STARTED COMING FROM THE COCKPIT ESCAPE HATCH. RETURNED TO THE FIELD WITHOUT FURTHER INCIDENT. MAINTENANCE REMOVED AND REPLACED THE CREW ESCAPE HATCH ASSEMBLY AFTER DETERMINING THAT THE ACRYLIC COVER HAD COME OFF.