Posts about: "EAFR" [Posts: 153 Pages: 8]

tdracer excellently summarised. But I'll confirm.
The switch is directly connected to the coils of a latching relay. That latching relay is directly connected to the coils of the spar valve. There is no digital logic device in the way,
The position of the switch is monitored (through a different set of contacts) by the EAFR (twice). The position of the spar valve is monitored by the EAFR.
Thus the recorder sees (twice) that the switch is moved, and that the valve moved in response.

The control path the engine HPSOV is likely far more important in his case as that valve is much faster acting the slow motor driven spar valve.

That's better than being at the mercy of speculation from the AAIB.

It's easy to go, "it must be suicide, there's nothing else in the preliminary report that explains it". Well, the things that might turn out to be a factor are not in the preliminary report because they're still being investigated. Fuel samples. The switches themselves, which suffered fire damage. A thorough understanding what can cause the transitions logged on the EAFR, and what did cause them.

YOU are one of the sources of "speculation of unknown origin".

Please stop this nonsense. There was no problem with the engines until one of the pilots set both fuel control switches to the CUTOFF position. Why is it so hard to understand that the change of position of the switches is the reason there was no thrust anymore? There is not a single report of a switch failure on any of B787 aircraft.

I am not aware of a part of the prelim report, second paragraph being discussed anywhere. Something I find, if I'm correct, not discussed yet for me surely very significant.
"The EGT was observed to be rising for both engines indicating relight. Engine 1\x92s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery . The EAFR recording stopped at 08:09:11"
Forgive my now 20 years into retirement as an F/O on the B737 400 and A320/21 but I still retain my lifelong avid interest in all things aviation. So am I correct in thinking this paragraph indicates significantly that eng2, right hand, core compressor had failed, albeit not explosively? It relit and fuel was being "re-introduced repeatedly "but could not arrest core speed deceleration". From day one I believed that no 2 failed after V1 and that the automatic correction for this on the 787 hid all but a possibly apparent small nose right on its climb out. Additionally I surmised that with all the warnings this produced, the low altitude and few seconds to address such a failure, the first recycle was offered up to the no 1 engine switch, in haste. The immediate result then RAT extension, a check on the engine parameters and an action on the no 2 switch, again in haste on realisation that was down on N2, then, sadly too late, No 1 recycled successfully. Unlike No 2. Heaven knows, a similar mistake was made on the Kegworth B737, when all he time in the world was available compared to AI171.
To me the long debate here about suicide is very unprofessional and surely this factual part of the report, has masses more credence, regardless of the consequences facing the AI crew.
If this bit about No 2 engine report is as I interpret, I would at least hope, if not already, someone else has picked it up, or at least it will get more attention ere long. God bless all the people so badly affected and I pray the cause will be one day revealed and not be buried to protect the money men. Has been known.

Yes, absolutely true. It has been mentioned before, but deserved to be again.

There was reasonable expectation that the front EAFR with battery backup would record some data, not least cockpit audio from at least one of the mics, but not the tail-mounted unit.

whether training explicitly covers it, only 787 pilots will know, but I would expect a pilot intent on crashing the flight would take the time to find out since it would likely be very relevant to that intent. It's one of the issues which clouds deliberate suicide as a probable cause of the crash.

Non-intentional behaviours or impulsive action... that's a different matter. In that instance, the pilot is likely not to have given it any thought - as per your post from which I partially quoted just now.

Totally wrong.

The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!

This is just *one * example of dozens of factual incorrect statements made by Mary Schiavo about aircraft accidents. I am surprised that any journalist still takes her seriously.

The displayed EICAS messages are very different when an engine is shut down via the fuel cutoff switch vice other reasons. The EAFR records those messages. I am quite sure they have eliminated the TCMA as a problem in this accident.

Indeed, there are dedicated parameters for TCMA:

Eng1_TCMA_Shutdown_Local_EEC_A
Eng1_TCMA_Shutdown_Local_EEC_B
Eng2_TCMA_Shutdown_Local_EEC_A
Eng2_TCMA_Shutdown_Local_EEC_B

Because the preliminary report can only contain verified factual information.
"There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB." - This will have been verified by the investigation team fairly rapidly. Verified reportable fact, included in the preliminary report.

This could not have been done by the team in the time available. Bear in mind that the EAFR was not read until almost 2 weeks after the crash. Before that point there would have been little focus on the fuel switches, which were recovered in the run position (verifiable and reported). Once attention was directed to the switches, a small team will form just to forensically examine those switches. They will likely take WEEKS to even begin the detailed examination of the switches. Those switches have been through a crash and a fire. They dare not move them until every possible non-destructive examination technique has been used. What do you test first? just pulling the sleeve will move something. Moving the lever will move the contacts. Did fingerprints survive the fire?. You would want to x-ray them, measure wear on the locking, look at contact position. Electrically test the terminals. Does it need to be opened? They would get examples from the manufacturer and destructively test them.

Yes in the final report they would be in a position to make a statement like that. But in the preliminary - No.

Several posts (I think - Pls don't ask me to find and quote) - have made statements to the effect of "we'll never know which person moved the switches".

Question to our active flight crew.
The EAFR records column / yoke angle and input force . It will be easy to show who was controlling the aircraft at any moment. Do you think that if for example the FO, whilst actively flying the aircraft was the one to reset the switches back to run, in changing to a single hand on the yoke and turning to the switches, there would be any detectable change in input force / angle ? Or would that detail be lost in the noise?

A visual inspection would verify if the body had a dog and the barrel lined up with it and was behind the dog. Report had nice big pics of exemplar switches and low resolution small pics of mishap switches.