Originally Posted by baobab72
If the PDU is using bleed air both for deploying and stowing the translating cowls, whta exactly happens when you press the emergency stow switchlight?
I'm not sure how much more you need than what the manual says, which is:
Originally Posted by challeger manual
As safety feature the thrust reverser system is comprised of an emergency stow system controlled by the respective UNLK switchlights on the THRUST REVERSER panel that when pressed it will direct 14th stage bleed air into the PDU returning the thrust reverser to the fully stowed position.
Or are you asking what physically happens in the PDU? I can tell you I don't know and I don't care, and I have just under 3,000 hours in CRJ-100/200 with the same engines and same reversers.
I will tell you this: when you're in the sim practicing an inadvertent deployment, make sure your hand is not in the way of the thrust lever that will be snapping back, because is snaps back violently quickly, they have hurt people.
All this is handled much better on the bigger CRJs.