Why - because so many are not FM immune?
Yes, most self fly hire spamcans aren't.
This is based on a sample size of 10-20 that I've been in. I don't think a single SFH plane I've been in was FM immune. In fact perhaps half of them had unserviceable instruments. I did my IMC Rating in several planes; one had a working VOR, another had a working DME (no ADF), another had a working ADF (and a duff but
apparently working DME). None had all three working.
So I do quite enjoy ownership now
