I recently simulated an engine fire (eng #2) during climb.  The fire came up at FL300 and was successfully extinguished.  I followed the PMDG QRH procedures.

Once the engine 2 was stopped, I checked my hydraulics and both systems were fine.

 

As I approached the airport for landing, the Hydraulic System B failed (no more pressure / "overhead" indicated for system B.   I was able to land using the alternate flaps.

 

My question; was the Hydraulic failure Syst B a result of the Eng 2 fire or was it a result of my (mis)management of the engine fire ?

 

I have completed this "simulation" a few times in the past and I am pretty sure I had the hydraulic problem each time. 

 

Thanks

 

 

My question; was the Hydraulic failure Syst B a result of the Eng 2 fire or was it a result of my (mis)management of the engine fire ?

 

I don't have the manuals in front of me, so I can't provide an answer directly, but doesn't the QRH note which other checklists to accomplish and the potential consequences?  I might be imagining things.

 

It would make sense to have a HYD B light, though, since ENG 2 has a mechanical pump to drive HYD B (though there is an ELEC backup).  My bet is that you still had some function because of the ELEC side of HYD B still working.

 

Take a look here (about 1/3 of the way down) to see what systems would be affected by a total failure of HYD B:

http://www.b737.org.uk/hydraulics.htm

Did you return to the airfield ASAP? With only one engine running you should plan to land at the nearest suitable airfield as soon as possible for this reason. If you continued on for ages to your destination no wonder it ran out of press.!

I had a look at the QRH for this emergency procedure. I don't understand why you would get a hydraulic B failure on the approach. The electric hydraulic pump should provide back up hyd pressure for the remainder of the flight. So, this failure of the B hyd sys does not make any sense to me either.

 

I'm surprised that the engine fire procedure doesn't have you check to make sure the electrical hyd B pump switch is ON. That surprises me. Here you have a full blown emergency with one engine shut down and the check list doesn't make sure your back up hyd elec pump is operating? The last thing you need at this point is a compounded emergency (loss of one hydraulic system added to the mixture).

You shouldn't lose the whole B system with an engine fire. You'd shut down the engine driven hydraulic pump, but the ELEC1 pump should still run.

I think there's some confusion on terms here...

 

Wouldn't you still get some sort of annunciation because the EDP is down, and you're only on ELEC?  If so, then the annunciation doesn't mean failure (despite the language used in the post).  It means that the EDP for Sys B is down.  Sys B's ELEC is just fine.

I actually lost all pressure in the Syst. B and when lowering the flaps the usual way, nothing happened.  So definitely lost the Syst. B.

I did return to the airport right away but it did take some time to descent from FL300.