As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLAP ACTUATOR JACKSCREW SEPARATED FROM THE ACTUATOR ASSEMBLY CAUSING FAILURE OF THE FLAP SYSTEM DURING TAKE OFF. TEAR DOWN REVEALED THAT THE JACKSCREW RETAINING NUT HAD LOOSENED AND SEPARATED FROM THE JACKSCREW ALLOWING IT TO BE PULLED FROM THE ACTUATOR ASSEMBLY. RETAINING NUT HAD NO SAFETY LOCKING DEVICE INSTALLED.