PA28 instructor on a training flight with student reported having control difficulties possibly rela...

Attributes
ACN	1588096
Time
Date	201810
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Other Traffic pattern
Route In Use	None
Flight Plan	None
Person 1
Function	Pilot Not Flying Instructor
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 300 Flight Crew Type 100
Events
Anomaly	Inflight Event / Encounter Loss Of Aircraft Control Inflight Event / Encounter Weather / Turbulence

Narrative:

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.

Original NASA ASRS Text

Title: PA28 instructor on a training flight with student reported having control difficulties possibly related to frost build-up on the wings.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.