Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Distraction; Troubleshooting
Aircraft Equipment Problem Critical
Aircraft Aircraft Damaged; Flight Crew Overcame Equipment Problem
Aircraft
Upon descent 15-20 miles from the ZZZZZ for arrival into ZZZ; I felt an un-commanded left wing down force upon the aircraft. I corrected by rolling wings level and looked at the wing and noticed the sheet metal had de-laminated on the inboard forward portion of the left aileron. I conducted a control check and the aircraft responded correctly with control inputs with a bit of extra right aileron force needed to keep the wings level. I continued to ZZZ and landed uneventfully. [The cause was the] age of aircraft or an improper bonding of the sheet metal to the surface underneath.
C402C Captain reported an uncommanded left wing down-force due to a delamination of a portion of the left aileron skin sheet metal.