"Brad Z" wrote in message
news:MJKzb.301460$9E1.1527176@attbi_s52...

I noticed that ATP Inc. uses two transponders in their Seminole trainers.
My understanding is that because many of the ATP locations only have one
plane, no maintenance shop, and operate out of class C airports, a faulty
transponder would effectively ground the airplane, making a "Four day"
multi
course a four week course.


A faulty transponder COULD effectively ground the airplane. ATC can
authorize operations without a transponder, but there's no guarantee they
will.