We have a Cirrus SR20 in our group. A months ago, the Alt-2 warning light started to come up intermittently in flight. Then from a weeks ago or so the ALT-2 light stays on irrespectable of the engine RPM.
When the ALT selector button is switched to ALT-2, there is no indication of charge on the AMP indicator infact the needle stays on zero.
Well, it sounds to me like a pretty straightforward case of Alt 2 failure, unless I’m missing something. It failed intermittently I guess, but now sounds like it’s dead.
I actually don’t remember whether the SR20 has the same shear coupling issue that the SR22 #2 alternators have - a plastic coupling which connects the engine accessory drive to the alternator can shear, which is one way alt 2 can die (again this may be SR22 only). You could also check the field wire for security - on SR20 ALT1s this has been a problem historically but not so much on the Alt2, since Alt2 is behind the engine and protected to a certain degree from the ram air in flight.
Otherwise, you may just have to pull alt 2 and send it for IRAN (inspection & repair as necessary).
The aircraft was taken to a maintenance organisation. The initial suggestion was that the “coupling” between the alternator and the small gearbox is sheared. So had to order the parts to Cirrus US. I will let everyone know if this is the only cause of problem.