Narrative:

I had planned a xc with a student to go to ZZZ with an expected diversion due to snow accumulation. The planned diversion was to be to ZZZ1. Notams were checked at both airports. ZZZ had no report for anything regarding snow-which was expected due to having this occurrence with a student before. However; I thought that ZZZ1 would have a NOTAM regarding snow condition or if the runway was unusable or closed due to the snow accumulation. No NOTAM was seen regarding that. At ZZZ diversion was initiated as planned. Upon coming to ZZZ1; we noticed that it looked like the airport was mostly still covered in snow. Upon flyover; we noticed that there was a thin plowed section on the runway centerline maybe 20 ft or less in width. I decided we would enter the pattern and fly the approach and decide whether to land or not. Landing was executed upon seeing runway centerline. I as the instructor should have been doing the full landing and on the controls. However; I let the student attempt to initiate the landing. We ended up getting out of the plowed portion and upon side pull; I took the flight controls. I put in lots of left rudder due to the unplowed portion pulling us to the right. We then fishtailed to the left and upon that right rudder was put in. Speed at this point had been reduced quite a bit and a stop was made just to the left of runway centerline. I then did a soft field takeoff remaining in the plowed portion. On review; I as the instructor should have been on the controls the full time during landing. 2nd lesson was that we should have just abandoned the landing due to the unplowed portion and the risk of side pull or ground control loss. 3rd lesson was to not expect an uncontrolled field to put out a NOTAM if the airport has snow on the runway or if the runway is unusable. No noted damage occurred to the aircraft and flight back was non-safety eventful.

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Original NASA ASRS Text

Title: A C172 instructor pilot allowed his student pilot to attempt a landing on a snow covered runway that had been plowed 20 feet in width. The student lost control; but the instructor regained control and they returned to their departure airport.

Narrative: I had planned a XC with a student to go to ZZZ with an expected diversion due to snow accumulation. The planned diversion was to be to ZZZ1. NOTAMs were checked at both airports. ZZZ had no report for anything regarding snow-which was expected due to having this occurrence with a student before. However; I thought that ZZZ1 would have a NOTAM regarding snow condition or if the runway was unusable or closed due to the snow accumulation. No NOTAM was seen regarding that. At ZZZ diversion was initiated as planned. Upon coming to ZZZ1; we noticed that it looked like the airport was mostly still covered in snow. Upon flyover; we noticed that there was a thin plowed section on the runway centerline maybe 20 ft or less in width. I decided we would enter the pattern and fly the approach and decide whether to land or not. Landing was executed upon seeing runway centerline. I as the instructor should have been doing the full landing and on the controls. However; I let the student attempt to initiate the landing. We ended up getting out of the plowed portion and upon side pull; I took the flight controls. I put in lots of left rudder due to the unplowed portion pulling us to the right. We then fishtailed to the left and upon that right rudder was put in. Speed at this point had been reduced quite a bit and a stop was made just to the left of runway centerline. I then did a soft field takeoff remaining in the plowed portion. On review; I as the instructor should have been on the controls the full time during landing. 2nd lesson was that we should have just abandoned the landing due to the unplowed portion and the risk of side pull or ground control loss. 3rd lesson was to not expect an uncontrolled field to put out a NOTAM if the airport has snow on the runway or if the runway is unusable. No noted damage occurred to the aircraft and flight back was non-safety eventful.

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.