It I am finding that my student is having a hard time getting over a landing plateau there are a couple different things that I would try to help them get over it. I would not just stick with just practice lessons the whole time. I would make sure that they still have some self cofidence in their flying. I would consider having them do some maeuvers that I know that they are good at. Maybe even have them go for a flight for fun or for pleasure. I would make sure they are still enjoying what they are doing.
I would also have them go out on a flight with another instructor. This has helped me out during my training and I think it would be great for anyone. It would provide them with another view on what they are doing. Maybe another person may notice something that you didn't notice or they may even have a technique for teaching leasons that you don't use that would work great for your student. They is no problem with doing this.
If you student is struggling there is no problem with going and talking to your supervisor early on. They are a great resource for you. They have great experience and may be able to help you or your student in aiding them to get over the plateau.
I am not sure exactly how many hours or reviews that I would wait till before I would have that "aviation isn't for you talk". I would make sure that I had worked with people and tried everything possible first. It would be a last resort for me and I hope to never have to do such a thing.
