IBob

I agree with all your above Onetrack. I programmed decades of automation (though not in aircraft). I had a lot to do with logging plant data, also examining it. And I have a strong troubleshooting background. On that basis I would like to add this: There are lots of posts here that assume the EAFR cannot be wrong, in either the data it logs, or the timestamps. So there seems to be a general acceptance that certain exact things happened at certain exact times. While I have no doubt that the people who design these systems do everything they can to ensure that, we cannot be sure that is so. The data accuracy depends on where the data is sourced and how robust that source is (in this case in accurately reflecting the state of some switches). We should not be simply assuming that the EAFR 'looks' at the switches. It is entirely possible that it 'looks at' something in the software that is interpreting the condition of those switches. In which case there is more to consider than just a couple of switches. Regarding the timestamps: the EAFR is sharing a common central comms bus with many other things. And it is capturing a broad array of data. Whether it grabs all this data pretty much in one burst, or a bit at a time, I don't know. But any major disruption of those central comms...or indeed any failure to answer by whatever provides the data... has the potential to put the time stamps out from the actual events.The timestamp is when the EAFR managed to source the data. We need to be confident of rapid uninterrupted data access for those timestamps to be taken as accurate. I write this not to further muddy the waters. But from the info provided, I think we should be saying 'The switches were logged off/on at these specific times.' Not 'The switches went off/on at these specific times.' I should end by saying that close inspection of the captured data and of how and where that data is sourced would clarify much of the above. And I am hopeful that there are impartial investigators with access to do that.

Some comments here are clearly so one-eyed and judgemental, I've taken to just skipping over them. Here are 787 Oral Notes that go some way towards describing the general layout of the electronics and automation: https://pdfcoffee.com/787-oral-notesdocx-2-pdf-free.html

Certainly the information released to date indicates that, Roundsounds. However, given the circumstances, I'm sure you would agree that all possibilities need to be investigated.

One would like to think so Thruster. But then we don't know what we don't know, and sometimes that means we don't know what to ask. For instance, a lot of contributors here seem to be locked onto the idea that the FDR is directly monitoring those switches. That may be so, but it is also entirely possible that it is monitoring something in the logic that is 'looking at' those switches. In which case one has to look not only at the switches, but at that logic. And, again for instance, nobody has thought to consider the approx 1 sec between the two switches being logged as off. Maybe that was so. But the FDR is accessing and logging a great deal of data, a bit at a time, presumably by repetitively scanning all the stuff it is supposed to pick up. That approx 1 sec could be due to the scanning rate, the difference between the time it looked at switch 1 then switch 2. For me a major red flag in all this is that it took place at rotation. That, to me, remains an enormous 'coincidence'.

Roundsounds, I watched part of an analysis that included pics from a flight simulator. There was an active display showing the fuel valve/s status. And unless you go through the switches and logic, including the power to those, you cannot say there is no connection between the two systems. In a perfect world, yes. But given what happened, I would not blithely assume that. I would check.

No it doesn't Roundsounds. What it actually says is "In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so." It says nothing about anyone observing that switches were in cutoff position. Maybe he saw the valves off in a panel display??? And you're missing the point about the EFAR, but I don't know how to explain it any clearer except to repeat that it quite possibly logs what the automation thinks the switch positions are......not the actual inputs from the switches. And that's a very important difference.

The media at large have jumped on 'the fuel was turned off' as one would expect. That leaves us with two possibilities: 1. The fuel levers/switches were indeed turned off. 2. Something downstream of those switches saw them as being turned off. Both possibilities need to be investigated as far as is possible. And for 2, it becomes very important to know where the FDR gets it's info on those switches. Because to investigate possibility 2 requires an inspection of everything from the switches to where the FDR picks up that info. Here I am guessing, but after years of process control work, including setting up a great deal of system monitoring and data logging, I would be surprised if the FDR is looking at the actual outputs from the lever switches. It is far more likely to be looking at some register in the automation that holds (or should hold) the state of the switches. In my opinion........

I think folk need to read and digest the whole Interim report to clear away some of the assertions. Some Boeings were fitted with switches without the lever latches. Very unlikely in this case but not impossible. As for retracting the undercarriage: it seems the RAT deployed almost immediately after rotation, with the engines commencing to shut down, after which they were fighting for their lives. They had no 'positive climb'.

Okay. I was trying to raise what I see as valid points. But they are hard to explain, so I'll leave it.

Which part of finding is not worth anything?

Which bit, Facthunter???

That's not the case at all, Thruster: My aircraft (for instance) has a little lever that turns a ball valve. The 787 has a switch that provides at least 2 outputs (one for each switch position, Off or Run) and I would lay odds that those inputs go to automation logic that interprets the switch position and makes a decision regarding the fuel valves etc. That logic would also be trying to deal with fault conditions (both inputs on or both inputs off) and deciding what to do then. It is interesting that the switch is reported as taking place immediately after liftoff.......which is also when the logic switches from ground to flight mode. There also seem to be the general assumption that the FDR info is taken straight from the switch. And maybe it is, but it seems likely to me that it is taken after the logic has decided where the switch is.

Some may find it easier to read the preliminary report in it's original form. It also has some pics: https://aaib.gov.in/What's New Assets/Preliminary Report VT-ANB.pdf

This muddies the waters some: file:///C:/Users/OEM/Downloads/EASA_SIB_NM-18-33_1.pdf And how on earth is this, quote : 'not an unsafe condition that would warrant airworthiness directive (AD)' ????????

The prinicipal suggestions that come out of that would seem to be: 1. Due to their mechanical design, those switches cannot be accidentally tripped. 2. For the aircraft to behave as it did (without yawing) they would have to both be operated more or less simultaneously. I did freelance industrial automation work for over 30years. Much of it was quite straightforward, but over half of any program I wrote would be made up of 'what ifs'. That is, how the system should respond in the event of a failure of some part of the equipment or system. (And I always made a point of running that past the actual operators or end users, the reason being that they, not management, were usually the most knowledgeable when it came to the process.) So, those switches are not just a couple of switches wired to fuel valve. My guess would be there will be switches or contacts for both open and shut positions. And that will go to some sort of logic, which operates the valves. And aside from normal operation, the logic has to include what if power is lost to a switch or switches, what if a switch fails etc. Also under what other conditions (if any) are the fuel valves allowed to change state. It would be very interesting to see the actual switch arrangement, circuitry and logic...........