As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT FAILED TO ENSURE THAT THE PILOT HATCH WAS FULLY LATCHED PRIOR TO TAKEOFF. DURING CRUISE THE PILOT HATCH CAME OPEN IMPACTING THE UPPER FUSELAGE & THEN DEPARTED THE ACFT. ACFT CONTROL WAS NEVER COMPROMISED. ACFT LANDED WITHOUT FURTHER INCIDENT.