Originally Posted by
Ewfflyer
Squawk it as failed, they can't fly 91 training with an open squawk.
According to what reg? It isn't required for VFR flying, but obviously, you cannot take it IFR. As long as they placard it as INOP, it is good to go.
91.213(d)(3)(ii)
Deactivated and placarded "Inoperative." If deactivation of the inoperative instrument or equipment involves maintenance, it must be accomplished and recorded in accordance with
part 43 of this chapter;