What was found
AFTER SLOWING DOWN TO THE REQUIRED INDICATED AIRSPEED FOR FLAPS, I LOWERED FLAPS TO 20 DEGREES. I CONTINUED TO SLOW DOWN BELOW FULL FLAP SPEED RANGE AND AT 5500 FEET MSL APPROX I LOWERED THE FLAP LEVER TO 30 DEGREES (FULL FLAPS). THERE WAS AN AUDIBLE “CLUNK” OF SOMETHING BREAKING. THIS WAS LATER DETERMINED TO BE THE CONTROL ROD FOR THE RIGHT WING FLAP. WHEN IT BROKE THE RIGHT FLAP IMMEDIATELY REVERTED TO BE LEVEL WITH THE WING (0 DEGREES), WHILE THE LEFT FLAP CONTINUED LOWERING TO FULL POSITION (30 DEGREES). I IMMEDIATELY LOST CONTROLLABILITY OF THE AIRCRAFT AND WE ROLLED AGGRESSIVELY TO THE RIGHT DUE TO THE ASYMMETRICAL FLAPS.