FGD135 is misinformed
Sorry mate but you are wrong. Once the torque on the failing engine falls below 400 ft lbs the autofeather armed light on the operating engine will extinguish indicating that the operating side autofeather is disarmed. Then once the failed engine torque falls below 200 ft lbs it will feather. That is what you are looking for in the autofeather (AFX) test sequence discussed above.
Groggy