Comment by histriosum
16 hours ago
> The report is actually a little cagey about whether the locks were properly installed on these switches. Said locks are supposedly optional.
The locks/gates on the switches are definitely NOT optional. There was an SAIB about some switches that may have been installed improperly. It didn't result in an AD, which likely means the extent was limited or potentially even nil.
The switches were moved to cutoff with a one second delay between the first and second switch. That's pretty suggestive of deliberate movement. I've flown a Max9 simulator, which has the same switches. Moving one of them by accident would be impossible, let alone two of them.
I agree with not jumping to conclusions about the pilots and possible motives or circumstances, but I will bet a lot of money that the switches were just fine.
The CVR will likely have audio of the switch movement to confirm as well.
The switch must be lifted and turned. The optional posts block you from inadvertently knocking the switch (that you must pull up and turn).
I second that it’s not an accidental motion, you must actively manipulate the switch. But just like your turn signal in your car, it is muscle memory when you use it. I just wonder what action the pilot mistook the fuel cutoff for. Looking around the cockpit shows just how unique those switches are and not something you mistake with another common activity.
Pretty sad day if this was an intentional action
> one second delay
did the report say a one second delay or that the two switches were turned off at consecutive seconds? The latter is what I remembered, but I'll check again.
The report can be found here: https://aaib.gov.in/What's%20New%20Assets/Preliminary%20Repo...
> did the report say a one second delay or that the two switches were turned off at consecutive seconds?
The report states, on page 14: The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec.
"with a time gap of 01 sec" seems fairly clear. The final report will have more granularity, but I don't think that's very ambiguous.
You are right, I was remembering the description of turning the switches back on.