Since it's relevant I will continue here.
It's complicated to understand what will happen from the FCOM. At least it's not crystal clear.
I am talking about THR LEVER FAULT + EIU fault at 500ft during takeoff.
2nd scenario THR LEVER DISAGREE + EIU fault at 500ft during takeoff.
Caution, I am talking only about takeoff, not during high speed and high Mach numbers.
I cannot understand if the thrust will be idle immediately after the failure due to Mach no being below 0.47, or conditions have to be satisfied to happen.
1st scenario:
As far I can explain and understand in THR LEVER FAULT plus EIU, you are at flex or toga, so FADEC normally is supposed to maintain takeoff thrust until slat retraction where it selects MCT thrust. However here slat position is already unreadable by FADEC due to EIU failure, so it should switch to approach condition due to Mach number, that is IDLE thrust (approach idle due to EIU). So practically there is nothing you can do, idle thrust is commanded. You can not delay it.
2nd scenario
THR LEVER DISAGREE plus EIU, assuming both TLA are above idle. Takeoff thrust is maintained normally until thrust reduction, at which point maximum thrust available is CLB thrust depending on the higher resolver position. After that point, it should trigger the approach condition when slats are extended. However again this is impossible due to EIU, so idle again due to low Mach number. So practically, you have idle thrust by the time you select CLB thrust in the thrust levers. It is noted in L2 as "If TLA at, or below, MCT and if the slats...". Practically here you can delay the idle selection by the FADEC.
Any corrections, suggestions?
Autothrust is out of the game due to EIU fault.
As autothrust is INOP, no alpha floor available.
What would happen in the other engine in this session can be questionable, but it depends on the scenario selected. I assume in the second scenario an engine fail could be managed with some speedbrakes and gear as long as CLB thrust is not selected on the discussed one.
Last edited by Lantirn; 23rd Nov 2016 at 14:54.