Posts about: "CVR" [Posts: 265 Page: 14 of 14]¶

Do you not consider the EAFR showing the cutoff switches switching to cutoff, followed by the engines spooling down, a smoking gun? Especially coupled with the engines restarting once re-enabled?

We had some discussions over in 787 GEnx loss of aircraft data will result in engine shutdown which I won't repeat in full, but there doesn't seem to be any credible way to get that result from a system failure without dealing in one-in-a-quadrillion events. The monitoring channel going to the RDCs and EAFRs is independent from the relay logic that closes the fuel valves.

Most of the "we'll never know" accidents don't have full FDR and CVR data. This one does.

I'm usually not on Boeing's side but the evidence is pretty overwhelming here.

Unless the CVR captured the sounds of a physical struggle. I suspect that those who have heard it have a better understanding of what happened than we do.

I'm not clear on what an "incorrect direction" would be in this context. Does that imply that when the switch was in the RUN position pushing it toward run caused it to easily move toward CUTOFF?

This requires more explanation to make sense.

Hmmm... Were it to have been a circuit breaker, how many times would a reset attempt be acceptable practice? But ultimately, it latched correctly in RUN. But then someone evaluated the switch locking, and reported as quoted above? This is all very slushy.

Though this discussion being about the RUN/CUTOFF switch(s) of a 787 being accused of improper operation, does this really relate to the Air India 171 crash? The reported information has already stated that both switches were selected from RUN to CUTOFF within a second, and then back to RUN, with a pilot remark about that action. It is a statistical infinity that on 171 both switches would fail into the cutoff position by themselves within a second, and there not be a pilot remark about that in the CVR, when there was a remark "Why did you do that?" associated with the switches.

I have moved a lot of switches and other controls in my flying career. In each case, I made that action with the intent that doing so would cause the desired action of a system. Moving the control itself was a means to an end. So, in moving the control, I determined that the ultimate objective was achieved. If there was a "feel" or locking system associated with the motion of the switch/control, then I would assess that too - was it working as expected? Like a flap or landing gear selector, I don't just push it toward the other direction, and hope that it pops into the desired position, I actually move the control the whole way, and confirm by feel/sight/locking device, that it is where I intend it to be, and will stay. Let's not forget that very basic expectation of piloting! Yes, there is the phrase "throw the switch", but that is for Igor. We pilots will move the switch the whole way, and assure that it got where it was going and is going to stay!

Both of these topics relate to the switch(es) in the 787, but I think that the similarity ends there.

One more vote for "It's a corporate culture thing." Let's think about what this implies about the pilots who wrote it up. Their company had a fatal accident that involved moving that switch within the last year. All aircrews are certainly going to pay attention to that switch, right? Right? And if it doesn't work properly, they will alert maintenance. Right? Right?
This smells of fish.
Well they (probably) did fill out the paperwork, but did they make sure that the switches worked? Did they replace any that needed replacing? A few months back I offered a thought that the full investigation may uncover some unknown details about aircraft maintenance at Air India.
Is this slowly coming to light as a result of the investigation?
Seconded.

Ver5pen , strongly suggest that you review the context (via the CVR summary, not transcript) from the accident aircraft's interim report. You are deliberately removing the context and timings of that event in your attempt to throw up a smoke screen. Not well played given that the type, model and series differences have been discussed as nauseum , and more to the point...Air India has had most of a year to take a good look at all of their switches in all of their cockpits and replace any found to be defective.

And was that done? If not, Why Not?

It could possibly be an interesting failure mode of the FCSs but a) it still appears to require significant (deliberate) force to make it happen and b) on the accident flight both switches go to cutoff and are left there for some considerable time before being put back to run despite the crew being aware of their unusual position for the phase of flight (CVR). Chances of this happening without pilot input infinitesimal?