I was enroute to EHEH yesterday in an Aerosoft CRJ 700 when avionics and the engine failed - do not ask me how or why as I do not know. So, I started the APU mid flight, and managed to restart both engines. There was a constant humming noise, and when I looked externally, I noticed this 'fan' at the front of the plane. I assume it is some form of a fan to generate power. Can some one enlighten me as to what it is, what cause it to be deployed, and how do you retract it?

https://www.dropbox.com/s/eo6l7nzprpmgz38/Aerosofr CRJ.jpg?dl=0

 

 

 

I don't own the CRJ, but it sounds like a RAT...

https://en.wikipedia.org/wiki/Ram_air_turbine

I suppose I could have looked at the photo... RAT indeed.

HTH- C

Edited November 13, 20214 yr by cavaricooper

It's the RAT (Ram Air Turbine), it pops out automatically when all the generators drop off line.

It generates electricity (and sometimes hydraulic pressure) so the aircraft remains controllable until a better source of power is connected.

It's normally a maintenance function to restow it so only when on the ground.

I think restowing it is one of the options on the tablet.

HTH,

Ian

We probably won't know what your failure was but the RAT operated as it is supposed to so you had some electrical power to the aircraft. When you land and park, there is an option in the tablet to stow the Ram Air Turbine as this is something that is only done by the ground crew.

It is the Ram Air Turbine (RAT). It will automatically deploy in flight if all AC generators are lost. It can also be manually deployed. It provides limited AC power for essential instruments and systems, and also energizes the number 3 electric hydraulic pump. It can only be re-stowed on the ground, and it is a two-person job to get it retracted and locked. In the sim, it can be re-stowed via the EFB.

It does make a very loud noise when deployed and running in flight.

As others have said it's the RAT and I have to say it's really cool that this life saving device is modeled. The most common scenario for automatic rat deployment (and loss of both engines) is fuel deprivation. What an ingenious system - even with no fuel on board, this simple device can harness the power of the aircraft's gliding momentum and the flow of air around the airframe to act like a mini turbine generator and provide just enough power to make the aircraft controllable enough to land. 

This video provides a great description of the rat at the 13 minute mark - but I recommend watching the entire video from beginning to end for the absolutely crazy story and the surprising root cause of the failure at the end of the video. 

 

Edited November 13, 20214 yr by enright
Adjusted video time stamp