Hello. I ran into suspicious behavior of the fuel system on BAe 146 and would like to know if it works as intended.
A long story
I have been flying with random failures enabled recently and got a right outer fuel pump failure in cruise. I shut the pump down and took no other action thinking the R standby pump would step in. It was only later I found that standby pumps do not supply fuel to the engines. IIUC the correct response would be to open the R common feed valve so that R inner pump feeds both engines 3 and 4.
Anyways, with the R outer pump both broken and off engine 4 soon starved and flamed out, which is understandable. I have landed succeffully on three engines and decided to handle this situation again in a practice flight. This is where things got a bit weird.
For the first test I have triggered the R outer pump failure manually in the EFB. FUEL and R OUTER LO PRESS annunciators have immediately turned on. Without waiting for the engine to shut down I have switched the pump off and opened the R common feed valve. The engine kept running normally as expected.
Then I decided to repeat the failure but let the engine flame out and restart it in flight:
R OUTER PUMP FAILURE (EFB): OFF
R OUTER PUMP: ON
R COMMON FEED: SHUT
R OUTER PUMP FAILURE (EFB): ON
Then I waited for the engine 4 to stop but, unlike the original flight, this has never happened. Switching the R outer pump off also did not interrupt the fuel flow.
As an experiment I have turned ALL engine pumps off and waited for a couple minutes but the engines just kept running normally at the same thrust setting (~80% N1).
I then triggered failures of ALL fuel pumps including the standby ones in the EFB. No effect, the engines kept running normally.
I have restarted the flight several times and tried both switching the pumps off and triggering fuel pump failures in different combinations. Switches never seems to affect anything. Triggering the failures, on the other hand, sometimes stops the fuel flow to the respective engine, about 1 time out of 10. In other cases only the annunciators are lit.
TL;DR
I found that turning some or all engine pumps off does not stop the fuel flow to the engines. This happens regardless of X FEED and COMMON FEED valve states. Is this as designed? I may still be missing something obvious about the fuel system.
I also found that triggering pump failures in the EFB rarely makes the pumps actually fail. In most cases only respective annunciators are lit but the fuel keeps flowing. Is this as designed? Could there be different kinds of the same failure (real ones and false positives)?
Other issues
While experimenting with this I also noticed other, more serious issues. I am not sure if all of them are known:
Loading a saved BAe 146 flight crashes MSFS 100% of the time. This used to work in earlier versions and still works with other aircrafts.
EFB occasionally hangs and becomes completely unresponsive. Hiding it and showing again has no effect.
Shape of the holding pattern perfomed by the autopilot in LNAV mode is far from the expected oval. It resembles an open envelope instead. This is already reported on the forum.
