Originally Posted by rickair7777

Good points.

Probably need three "stops"...

1. TOGA
2. Get to use the motor again, maybe need a borescope
3. Might blow the motor immediately, probably need a rebuild but we're going to die anyway

The CRJ 200 (no FADEC) SOP used to be to set a MAX rated power for WS/GPWS.

Then the FAA decided that wasn't good enough, and they eventually required us to use firewall thrust. That provided a little extra thrust, but usually resulted in an overtemp which required a call to MX. Usually they looked up the Temp vs. time and said good-to-go. Occasionally a borescope was required, which grounded the plane.

The firewall was a hard stop, and seemed to be about #2 on the scale above. Since usually no borescope was required, there was obviously some margin left in the motor. That was a good thing, because the automatic WS detector went off a lot, and it would be impractical for each crew to destroy a motor every week or two which was how often we got WS warnings in some hubs.

So stop #2 would be used for "routine" nuisance WS/GPWS events, with little or no economic impact.

Stop #3 would be available if the crew decided that impact was likely. That setting would be as much thrust as the motor could achieve with some non-zero statistical threshold of catastrophic failure.


In my experience, using stop #3 immediately for all WS/GPWS would bankrupt the airline pretty quick.