Hi, I am trying to understand the sequence of the events to be unfolded into a given situation.
The first failure that will come into play is:
FUEL L(R) TK PUMP 1+2 LO PR
-If NO FUEL LEAK:
FUEL X FEED (IF ABOVE FL150)....ON
1) Why specific FL150? If we are below why we keep it OFF?
ENG MODE SEL...IGN
TK PUMP 1 (AFFECTED)....OFF
TK PUMP 2 (AFFECTED)....OFF Let's assume that left hand pumps are the ones inoperative.
At this point, left hand fuel pumps are off, the xfeed is open, so both engine consuming from the right hand engine. From now on we have some other sub cases, like where the failure happened. Let's assume again that the failure happen at FL 350 and we were there for 35 minutes, so the GRAVITY FEED CEILING is current FL.
The procedure continues:
WHEN TK (AFFECTED) FUEL RQRD:
TK (AFFECTED) FEED....GRVTY ONLY
If at this point we go to the procedure of the feeding it says:
ENG MODE SEL...IGN
AVOID NEG G FACTOR
MAX FL:GRAVITY FEED CEILING which is FL350 for us.
When reaching gravity feed ceiling:
FUEL X FEED...OFF
2) So in the beginning we had the x feed ON and the right hand side was supplying. Now the procedure asks us to put it OFF. So from what I understand, the right hand engine will continue to consume the inner/outer tank fuel, xfeed seperated the two sides, and the Left hand pumps are off due low pressure. From what I get is that the left hand engine will shut down from fuel starvation.
3) At this point if we lose one engine, we can't maintain FL350, so we have to pick another Gravity fuel ceiling?! Then we continue.
If no fuel leak and with one engine running (fed by gravity): which in my mind translates us first part no fuel leak (check) AND this one engine running (we have only one because the other one shut down) is fed by gravity.
FUEL X FEED...ON, so again put it on
BANK ANGLE...1 degree down on the live eng side
RUDDER TRIM...USE
When fuel imbalanve reaches 1000kg:
BANK ANGLE...2or3 degrees on the live eng side.
Now if we continue the
FUEL L (R) TK PUMP 1+2 LO PR procedure from the place we left it goes as follows:
WHEN TK (AFFECTED FUEL RQRD:
TK (AFFECTED) FEED .... GRVTY ONLY Let's assume we diverted and one engine could supply us to the diversion airport.
FUEL X FEED (IF BELOW FL150)...OFF
4) This question probably is the same with the first. Why it asks to switch it off again and specific below FL150? and then again
If FUEL X FEED off:
PROC: GRVTY FUEL FEEDING (here is has a note saying: As long as the fuel x feed is closed, associated engine is fed by gravity only).
AVOID NEGATIVE G FACTOR
I really don't know if I have burnt myself up, or if I am missing something system wised and I can't get the whole concept, but it seems a bit difficult to me to understand it.
I haven't seen it in the simulator to be honest, maybe it would have been more clear that way, but you work with what you have.
Thanks in advance anyone who will try to explain it to me.