So the book says:
During normal operations the EEC opens the reverser isolation valve (when all actuation requirements are met).
EEC will inhibit reverser isolation valve actuation unless aircraft is on the ground.
FCOM 2:
Fire Switch pulled:
- arms fire bottles
- closes fuel valves
- closes bleed air valves
- trips generators off
- shuts off hydraulic fluid to EDP
- depressurizes EDP
- removes power to the thrust reverser isolation valve
Everything prior to that is ‘regular’ airplane stuff but why the need for removing electrical power to the isolation valve?
Yes airborne you wouldn’t want thrust reverser deployment, however you don’t meet the actuation requirements except thrust lever idle.
EEC is not unpowered so should still prevent inadvertent deployment.
During normal shutdown on the ground the EEC is unpowered after 2(?) minutes.
I don’t see why that would make a difference as no EEC would mean no TR deployment either.