Transponder Gremlins
Yesterday I was alerted by a helpful ATCO that my mode C was returning erratic altitudes ranging between FL11 and 4500ft when actually I was level at 1300ft.
Before I commit to having it investigated and repaired has anyone here experienced similar goings on and if so what was the fault? I should say that it's a King KT76A not sure what the ALT encoder is though.