44 minutes ago, nauseus said:

 

I've  just looked over the specs again but no help. So, show me how the locking feature can be disengaged, please?

Ask the FAA, their SAIB said the locking feature was disengaged on some planes.

 

I tried to look at switch specs and instructions too out of curiosity.  An indian newspaper said the switch was honeywell type 4TL837-3D.   

 

I googled that, but I didn't get very far except to see that many varieties of locking positions were sold as options. 

 

But you had to order just one option, rather then buy a multiple option one and configure it yourself.  

 

Maybe in 2018 it was possible to select the purchase of a disengaged option or one you could choose the locking position yourself.   But thats just  guessing on my part.   The SAIB needs to explain more details of what disengaged means.

 

It would be nice to see a video of a disengaged switch in operation and see how easy or not it would be to flip the switch down.    We've seen a lot of videos of non-disengaged switches and they seem suitably resilient to accidental movement.

 

 

1 hour ago, deejai33 said:

Ask the FAA, their SAIB said the locking feature was disengaged on some planes.

 

I tried to look at switch specs and instructions too out of curiosity.  An indian newspaper said the switch was honeywell type 4TL837-3D.   

 

I googled that, but I didn't get very far except to see that many varieties of locking positions were sold as options. 

 

But you had to order just one option, rather then buy a multiple option one and configure it yourself.  

 

Maybe in 2018 it was possible to select the purchase of a disengaged option or one you could choose the locking position yourself.   But thats just  guessing on my part.   The SAIB needs to explain more details of what disengaged means.

 

It would be nice to see a video of a disengaged switch in operation and see how easy or not it would be to flip the switch down.    We've seen a lot of videos of non-disengaged switches and they seem suitably resilient to accidental movement.

 

 

 

Yes, the FAA SAIB NM-18-33 mentions 737 airplanes with fuel control switches being installed with the locking feature disengaged but does not explain the actual meaning of that. It later lists other Boeing models with different but similar toggle switches recommended for each.

 

These switches are advertised as military grade and probably last for decades but may break or get damaged like anything else. The final paragraph of the recommendations section eventually says: "we request that owners and operators report any failure of the locking feature of the fuel control switch to Boeing". This is the first use of the word "failure" in the report and implies that the switches should be initially installed as the specified, functional (lockable) units, which must be the case.

 

There is no definition of the "disengaged", what that means, or if it's even an option? 

 

 

 

1 minute ago, nauseus said:

 

Yes, the FAA SAIB NM-18-33 mentions 737 airplanes with fuel control switches being installed with the locking feature disengaged but does not explain the actual meaning of that. It later lists other Boeing models with different but similar toggle switches recommended for each.

 

These switches are advertised as military grade and probably last for decades but may break or get damaged like anything else. The final paragraph of the recommendations section eventually says: "we request that owners and operators report any failure of the locking feature of the fuel control switch to Boeing". This is the first use of the word "failure" in the report and implies that the switches should be initially installed as the specified, functional (lockable) units, which must be the case.

 

There is no definition of the "disengaged", what that means, or if it's even an option? 

 

 

 

 

I took it to be a very clever way of saying it was missing!!!!!

Just now, Will B Good said:

 

I took it to be a very clever way of saying it was missing!!!!!

 

I doubt that but there are hundreds of similar (looking) switches for numerous applications so it could be possible to install a wrong switch type that does not have the locking feature. 

 

 

New Details in Air India Crash Probe Shift Focus to Senior Pilot

 

Black-box recording and report details indicate the flight’s captain switched off fuel flow to engines

 

New details in the probe of last month’s Air India crash are shifting the focus to the senior pilot in the cockpit.

A black-box recording of dialogue between the flight’s two pilots indicates it was the captain who turned off switches that controlled fuel flowing to the plane’s two engines, according to people familiar with U.S. officials’ early assessment of evidence uncovered in the crash investigation.

The first officer expressed surprise and then panicked, these people said, while the captain seemed to remain calm.

The Wall Street Journal

MORE:

https://archive.ph/2QYNP

^Sounds like suicide by the Captain 

On 7/17/2025 at 3:50 PM, Nick Carter icp said:

^Sounds like suicide by the Captain 

Something I suggested way back when the thread(s) started, as has happened before, but why kill all of those people if he just wanted to end his own life.........but I guess someone with a troubled mind just doesn't think straight.

 

Such a shame/tragedy.

http://hibdz.skydiving.co.uk/757/767_tech/engines_and_apu/_popup_ib_2000_1_dual_engine_failure.htm#:~:text=If EGT rises rapidly approaching,drifting down from higher altitudes.

 

Quote

 

The difficulty in obtaining a rapid restart from a dual engine failure or flameout at high power settings is residual heat in the engine. The engine may restart into a stall, which may result in a hot start. Placing the Fuel Control switch to CUT OFF if the engine appears stalled or approaches the EGT start limit, clears the stall. Returning the switch immediately to RUN "reschedules" the engine control and allows the start to continue. EGT drops rapidly when the Fuel Control switch is placed to CUT OFF. "Cycling" the Fuel Control switch is more effective than waiting for the engine to cool with the Fuel Control switch in CUT OFF while engine RPM decelerates. By cycling the Fuel Control switch, higher N2 (or N3), and high pressure compressor (HPC) airflow may be sustained during the start attempt. This cycling increases HPC cooling, minimises RPM loss, and may reduce the overall time required for a successful restart.

 

The difficulty in obtaining a rapid restart from a dual engine failure or flameout at high power settings is residual heat in the engine. The engine may restart into a stall, which may result in a hot start. Placing the Fuel Control switch to CUT OFF if the engine appears stalled or approaches the EGT start limit, clears the stall. Returning the switch immediately to RUN "reschedules" the engine control and allows the start to continue. EGT drops rapidly when the Fuel Control switch is placed to CUT OFF. "Cycling" the Fuel Control switch is more effective than waiting for the engine to cool with the Fuel Control switch in CUT OFF while engine RPM decelerates. By cycling the Fuel Control switch, higher N2 (or N3), and high pressure compressor (HPC) airflow may be sustained during the start attempt. This cycling increases HPC cooling, minimises RPM loss, and may reduce the overall time required for a successful restart.

 

 

https://i2.res.24o.it/pdf2010/Editrice/ILSOLE24ORE/ILSOLE24ORE/Online/_Oggetti_Embedded/Documenti/2025/07/12/Preliminary Report VT.pdf

 

 

 

 

ie. Twin engine failure on take off, muscle memory in the captain goes through engine restart drill, first officer, less experienced, wonders aloud why, curt response from captain warns to stay focused, because in those seconds, he isn't thinking of shutting down the engines, he's trying to restart the, The RAT has deployed more or less at the same time; does cutting out the fuel via a cockpit toggle switch cause RAT to be deployed that quickly? Sole survivor recounts flickering lighting.

 

The preliminary crash report doesn't give the time the RAT deployed except that it was immediately after takeoff.