Jump to content
Sign in to follow this  
craig_read

Autothrottle OFF Alert Question

Recommended Posts

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

Share this post


Link to post
Share on other sites

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.

  • Like 1

Dan Downs KCRP

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

 

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)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
×
×
  • Create New...