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craig_read

Autothrottle OFF Alert Question

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Hi,

I was watching a video of a real 747-400 pilot flying the PMDG QOTSII and he made a comment re the audible alert of the Autothrottle being turned to OFF..

Ref: @ at 50:50 ish...

 

"and that autothrottle alert, doesn't actually happen.. in real life."

My question is.. is he correct for all 744's.. should it be audible if disarmed during taxi?  Or is it a company option thing?  Also.. I noticed on startup he has Autothrottle OFF and switches it to ARM during taxi to the runway.. in most of my flights it's in the ARM position all the time.. even when shutdown at the gate.. again is this simply a 'company procedure' thing?

Cheers

Craig

 


Craig Read, EGLL

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As for most such things, there are differences between company procedures; however, the Boeing preflight checklist includes arming the autothrottle (FCOM NP 21.20).  There is an EICAS caution message when autothrottle is disconnected either manually or automatically, but my understanding is that pressing the autothrottle disconnect button twice will cancel the caution message.  See also FCOM 4.20.8.

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Dan Downs KCRP

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Yeah I thought there might be differences, I guess the Boeing procedure for arming during pre-flight makes sense.. most of the time I imagine it's just left on.  A lot of real flight deck videos (in fact nearly all) I have seen have the Autothrottle switch set in the ARM position, event at the gate/ramp during loading.  That part must be company SOP based I guess, what makes me suspect this is this company checklist https://www.onebag.com/popups/747checklist.pdf which has autothrottle armed at line-up.  The FCOM at no point in normal procedures actually sets the Autothrottle to OFF either as far as I could tell... Anyway just so long as my mode of operation is not 'incorrect' I am content!  It would seem the autothrottle selection used by his company is a bit unusual.

But on the subject of the audible alert.. for Autothrottle to OFF while taxiing to the gate, the pilot here is specific in saying this doesn't happen in the real aircraft.. I guess the question is.. do we know if this is a configurable item and therefore is probably correct for his company's 747's.. or is it an oversight?  I don't know the answer so I was just asking the question, I didn't consider it a 'support' item as I don't know whether or not this is an error... I appreciate regardless you'll see the EICAS message.. it's the audible that I was querying..

Cheers

Edited by craig_read

Craig Read, EGLL

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14 minutes ago, craig_read said:

But on the subject of the audible alert.. for Autothrottle to OFF while taxiing to the gate, the pilot here is specific in saying this doesn't happen in the real aircraft.. I guess the question is.. do we know if this is a configurable item and therefore is probably correct for his company's 747's.. or is it an oversight? 

I've not got access to the manuals at this specific moment to double check the conditions of the A/T disconnect audible alert, but it seems plausible to me that it shouldn't sound in this case on the basis that the A/T is not active and therefore is not being disengaged - merely disarmed.


Simon Kelsey

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1 hour ago, skelsey said:

ut it seems plausible to me that it shouldn't sound in this case on the basis that the A/T is not active and therefore is not being disengaged - merely disarmed.

Sounds plausible to me, too. I haven't heard the A/T aural simply by putting the switch to OFF on the ground. There would have to be at least an active mode shown on the PFD FMA.

There are a few airlines which only arm the A/T just before entering the runway for safety reasons. My old airline wasn't one of these. The odds of the TOGA switches being pushed accidentally are pretty remote (and easily cancelled).


John H Watson (retired 744/767 Avionics engineer)

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