1. What caused the system to "think" there was a No.2 flameout at Point 1? Before that the engine indications should still have looked normal to the crew, but it seems they had no chance to override the spool-down that resulted, and perhaps no reason to think they needed to.
2. Why was PL1 retarded 10 seconds after Point 1? It wasn't to shut down the engine as it was only a 10degree change.
3. At Point 2 they seem to have ignored the normal readings of No.1 and the "Idle" readings of No.2, and shut down No.1 Is this a "confirmation" problem because they were expecting No.1 to be a problem before they set off? Also, would the windmilling No.1 "confirm" they were shutting down the bad engine?
4. Why did retarding PL2 clear the erroneous Flame Out condition (not just cancelling the warning, but also bringing up the fuel flow and unfeathering)?
5. If they had retarded PL2 at Point 3 instead of trying to restart No.1, would they have got out of the situation in time?
6. (Unimportant) What's with the three triangle-wave traces?
Very interesting analysis HDRW.
1. Could the ATPCS system have erroneously activated and feathered prop #2? It looks like a distinct possibility.
2. We will have to wait for the CVR for that one.
3. We will have to wait for the CVR for that one.
4. I believe that as part of the start sequence for eng #1 the crew selected the PWR MGT switch to MCT, thereby cancelling the autofeather signal from the ATPCS system, this i think caused eng #2 to begin to revert to normal.
5. I don't think so, as I believe this to be an ATPCS issue.
6. I have seen DFDR spikes before and they seem to appear when the recorded value is 0, some sort of "noise" on the recording, I am certain that they are not relevant to the accident.