B777 GE 90 Fire Switch / Thrust reverser Isolation valve

[B2N2]

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.

[flightleader]

Try look at it from an angle that is to minimise risk of fire.

[B2N2]

Well...since we started with a fire.....
So far I've come up with the following:
ACDP remains pressurized and fully operational with the assumption it could provide hydraulic pressure for TR actuation
TR Isolation valve is apparently mounted in the pylon on the 76, sounds reasonable to consider same in the 77.
I've just been reading again about the Lauda Air inflight TR deployment here:
https://www.aviation-accidents.net/report-download.php?id=181
Leads me to believe that de-powering the TR isolation valve would prevent an inadvertent TR deployment due to combinations of electrical short/valve contamination.
But this is all conjecture based on a lot of maybe's on my part as the accident aircraft had PW engines.