A question for the 777 guys
 

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WEIRD BUT TRUE.

This FMA Shows that the associated A/THR is presently not LINKED to the ALT HOLD MODE (pitch of A/P)

The TARGET Speed magenta bug is missing.

The question is HOW DID WE REACH THIS STAGE?

Looks like the autothrottles are off.



Shock / horror :eek:

Why should it disappear? A target bug is always a handy reference even if the A/T is not controlling the airspeed?

A/T is off ( obviously!! ) you are in ALT mode so either VNAV isn't available or you've selected ALT.

No computed data being received to display commanded Speed on the PFD...

Possibly an FMC reset or fault with the FMC master. Try switching to L or R FMC.

Either way you are in control of the speed....until it resets itself.

This is a failure of the MCP speed window. Selecting ALT should result in SPD, the speed window was unable to open or send the info, it cannot use VNAV(FMC info) with ALT as the vertical mode.

Selecting VNAV would probably rectify the situation as the data would come from the FMC rather than the MCP.

Not necessarily.

Selecting ALT would result in SPD only if the A/T is engaged. If it's disarmed with the 2 switches on the MCP it will be blank. ( same also if the A/T disconnect switch is pushed on the Thrust levers???? )

The --- magenta dashes mean "no computed data" from memory.....

Either way it's not normal....

With ALT selected the no computed data is from the MCP the auto throttle mode means nothing. Yes it's disconnected but it's not faulty no mode doesn't mean a fault, it would obviously disconnect with no data but that's what it should do.

So as I said providing speed data from the FMC would no doubt allow the auto throttle to have useful data.

Yes true, if you are in ALT then the SPD does come from the MCP.
So thinking more about it then you'd be correct, the fault resulting in no computed data would be in the MCP. VNAV may well fix the issue....

It's been 5 years since I flew the tripple and 12 since ground school...!

The one thing I like about Boeing is they're very logical, but I imagine those days are gone with the 787 I hear it's right up there with Airbus PFM. :ok:

I know the 747-8 reminds me of the Airbus it's definitely got some complicated magic going on in the background. The MCP is definitely connected via a computer now as it does things that don't appear as hard wired like the older Boeing's