As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE MAINTENANCE BASE HEAVY CHECK FOUND THE RIGHT SIDE WEB CORRODED UNDER THE AILERON TORQUE TUBE BETWEEN FRAME 12 AND FRAME 13 AT STRINGER 21 RIGHT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND INSTALLED NEW WEB BETWEEN FRAME 12 AND 13, IAW SRM 51-40-02. THE AIRCRAFT WAS RETURNED TO SERVICE.