CRJ-100/-200 Automatic Power Reserve
 

Has there ever been an instance of uncommanded activation of APR ?

What are the parameters for activation of ARP?

Lose an engine within 5 minutes of takeoff, APR kicks in...something like 2% 500# thrust/side...

...is that the talk about why there's a CRJ in the VIP lounge?

Cheers
George

Hi.

THe VIP lounge reference is about a CRJ-100 crash in Kigali, Rwanda, where an engine was at full power and could not be shut down. The plane's brakes failed and it crashed into the tower building. The other engine was successfully shut down after takeoff.

cliff
NBO

I'm sure there has been, but I can't find any proof.

If you meet the parameters to arm APR, then the only requirement for activation is a drop below 67.6% N1.

I never had an uncommanded activation of APR, but twice while doing a reduced thrust takeoff I had one engine decide to bump up to TOGA power halfway down the takeoff run.

Funny you should mention this. The airplane I flew yesterday had the APR deferred. It came on umcommanded in flight for a previous crew but apparently it wasn't an issue as the engine responded the the throttle inputs just fine.

Details
 

Anyone have the breakdown on what exactly took place. I saw where someone said they shut one down in flight and returned to the field SE. But then why would you taxi to the gate with one engine running wide open? I think I would have stayed on the runway with the AC pointing in a safe direction ( Like a grassy area )until we could get the thing shut down.....was the Engine fire Push swith not pushed?....details anyone?

I had a similar instance to this out of MSP a year or so ago. APR just came on out of nowhere, stayed on for a few minutes and went off by itself. Unknown why it was tripped, nothing was abnormal prior to it going off.

APR would not have caused this accident IMO. It simply boosts the fuel schedule...ie it adds some fuel to what is already manually selected. If you are at flight idle, APR would simply increase RPM a little bit...it would not cause th engine to go to full power.

If BOTH engines were at full power, there is only one common point between the two engines that I can think of: The throttle cables (they are cables on the 100/200). A structural failure along the path of the cables might have pinched them and jammed them so they could not be moved. Or they might have been cut or broken, which would leave the engines in whatever power setting they were selected at when the cables failed.

Also, you don't need the throttles to shut the engines down, the respective Fire Switchlight will do it for each engine. If the throttles cables AND the fire system failed...well they would be very lucky to get on the ground in one piece, cuz there must have been some serious problem with that airplane.