PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 50; Flight Crew Total 300; Flight Crew Type 100
Situational Awareness
Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control
Weather; Human Factors
On downwind abeam the PAPI the aircraft began banking to the right. My student was at the controls; and I asked why she was banking. She said it wasn't her. I immediately took controls and began to try to bank the aircraft to the left. The controls were unresponsive. I increased left aileron and the plane banked to the left about 5-10 degrees. I tried to correct back right and the aircraft began banking left and right about 4-5 times. On base and final the aircraft responded normally. This event occurred on the second lap in the pattern. The previous lap was normal. There was no visible frost on the wings in flight. Originally; I did not think frost was the problem; but upon further reflection I believe that was the issue. I believe that frost built up on taxi and on the first lap in the pattern that was not visible from the cockpit due to the sun's glare on the wings. When we shut down I noticed a decent amount of frost that had built up on the wing on our taxi back.
PA28 instructor on a training flight with student reported having control difficulties possibly related to frost build-up on the wings.