Failure of Auxiliary Vacuum
Lost my primary vacuum pump while in flight. Switched to auxiliary vacuum. Worked for a while then also quit. Returned home safely. Called my A&P and found out the auxiliary vacuum does not work when operating at max power. This was confirmed during my flight because it failed during the climb and started working again when I reduced power for the decent. Does anyone know why the auxiliary vacuum does not work when using max power? Is it to protect the instruments when vacuum is too high? Thanks!