Welcome, Guest. Please login or register.
Did you miss your activation email?

News: Precision Simulator update 10.85 (23 July 2019) is now available

Author Topic: Preflight test of A/P & A/T disconnect alerts  (Read 1110 times)

Hardy Heinlin

  • Moderator
  • Join date: May 2009
  • Posts: 10667
    • Aerowinx
Preflight test of A/P & A/T disconnect alerts
« on: Thu, 20 Jun 2019 23:40 »
Good evening,

I wonder if this is an airline option or type specific. So this is a question for all pilots and engineers of any aircraft type, be it Boeing, Airbus etc.

During preflight, when all automation is disengaged, do you push the autopilot disconnect switch on the yoke for an alert test? If so, will a continuous sound loop start or just a short sound? If a test alert occurs, do you need to reset it by a second push?

Is there a similar test for the autothrottle disconnect switches on the thrust levers?

Thank you!


Regards,

|-|ardy

Mariano

  • Join date: May 2009
  • Posts: 592
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #1 on: Fri, 21 Jun 2019 00:05 »
Hardy,

We (crew) do not perform such tests. I will try it tonight and get back to you.

Best regards,

Mariano

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #2 on: Fri, 21 Jun 2019 02:46 »
Also, are there associated messages?

I recall the A/T has no sound, but a message, but my memory is fading. I don't know if it depends on how long the button is pushed (to generate the A/T message).

emerydc8

  • Join date: Jun 2015
  • Location: Tucson, AZ USA
  • Posts: 1772
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #3 on: Fri, 21 Jun 2019 03:14 »
Never did it on the -400, but on the classic we'd get the wailer when we disconnected on the preflight.

[EDIT]
Quote
During preflight, when all automation is disengaged, do you push the autopilot disconnect switch on the yoke for an alert test?

I misread your question. If the A/P was already off, I'm pretty sure you wouldn't get any wailer if you hit the yoke disconnect.
« Last edit: Sat, 22 Jun 2019 11:34 by emerydc8 »

Mariano

  • Join date: May 2009
  • Posts: 592
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #4 on: Fri, 21 Jun 2019 13:21 »
Hardy,

Below, please find three very short videos.

Video 1 shows what happened when I pressed and quickly released the yoke A/P Disconnect button. I only got a blink of the amber A/P DISC discrete light, and the wailer.

https://www.dropbox.com/s/hsx2hl90x836qul/Video%20Jun%2021%2C%2003%2000%2029.mov?dl=0

Video 2 shows what happened when I held the yoke A/P Disconnect button pressed. Amber A/P DISC discrete light, Master Warning, EICAS AUTOPILOT DISC Warning message, and wailer activated (for as long as button was held in).

https://www.dropbox.com/s/kcbzesqj1dwyfnr/Video%20Jun%2021%2C%2003%2000%2034.mov?dl=0

Video 3 shows what happened when I pressed and released and then pressed and held the thrust lever A/T Disconnect button. Only the amber A/T DISC discrete light illuminated.

https://www.dropbox.com/s/90sszzm95ckyjgh/Video%20Jun%2021%2C%2003%2000%2044.mov?dl=0

I assume the difference in system response between the first and second videos was caused by me not holding the A/P Disconnect button long enough to allow time for all visual and aural warnings to activate.

I asked the engineer and he said that those tests are not part of his daily or transit (line) checks.

Best regards,

Mariano
« Last edit: Fri, 21 Jun 2019 15:04 by Mariano »

Hardy Heinlin

  • Moderator
  • Join date: May 2009
  • Posts: 10667
    • Aerowinx
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #5 on: Fri, 21 Jun 2019 14:52 »
Thank you, Mariano.

I think the 744 will behave similarly; it will just trigger EICAS messages (and associated lights and sounds) instead of the 767 specific system lights.


Regards,

|-|ardy

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #6 on: Sat, 22 Jun 2019 02:08 »
Quote
Video 3 shows what happened when I pressed and released and then pressed and held the thrust lever A/T Disconnect button. Only the amber A/T DISC discrete light illuminated.

Strange. I still have the recollection that the A/T EICAS msg appeared after some delay. Was your A/T switch armed?

emerydc8

  • Join date: Jun 2015
  • Location: Tucson, AZ USA
  • Posts: 1772
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #7 on: Sat, 22 Jun 2019 03:01 »
Thanks, Mariano. I would have never thought you could get the wailer just by pushing the yoke disconnect without the A/P being engaged.
Jon
« Last edit: Sat, 22 Jun 2019 11:33 by emerydc8 »

Mariano

  • Join date: May 2009
  • Posts: 592
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #8 on: Sat, 22 Jun 2019 14:11 »
John,

I thought likewise, but the EICAS message never triggered. We do not disarm the A/T unless an abnormal procedure dictates so, which I think is different from the 744.

I will try holding the switch in a bit longer today, just to make sure.

Best regards,

Mariano

mark744

  • Join date: Feb 2015
  • Posts: 77
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #9 on: Sun, 23 Jun 2019 10:44 »


I think the 744 will behave similarly; it will just trigger EICAS messages (and associated lights and sounds) instead of the 767 specific system lights.


Regards,

|-|ardy

Exactly so, checked a few nights ago.
Regards,
Mark.

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #10 on: Sun, 23 Jun 2019 15:19 »
The same pin on the B767 A/T computer outputs to the annunciator light and to the EICAS Computer. The logic in the EICAS computer only shows a 1 second delay on the message.

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #11 on: Wed, 26 Jun 2019 09:23 »


I think the 744 will behave similarly; it will just trigger EICAS messages (and associated lights and sounds) instead of the 767 specific system lights.


Regards,

|-|ardy

Exactly so, checked a few nights ago.
Regards,
Mark.

So you did or didn't get an A/T message on EICAS, Mark, with a long switch push?
« Last edit: Thu, 27 Jun 2019 07:21 by John H Watson »

mark744

  • Join date: Feb 2015
  • Posts: 77
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #12 on: Wed, 26 Jun 2019 22:39 »
I did get a continuous message and aural, as long as the button was pressed.
Regards,
Mark

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #13 on: Thu, 27 Jun 2019 02:02 »
I did get a continuous message and aural, as long as the button was pressed.
Regards,
Mark

A/T aural? Was this after engine start? 
« Last edit: Thu, 27 Jun 2019 07:21 by John H Watson »

mark744

  • Join date: Feb 2015
  • Posts: 77
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #14 on: Thu, 27 Jun 2019 04:06 »
After engine shutdown

Hardy Heinlin

  • Moderator
  • Join date: May 2009
  • Posts: 10667
    • Aerowinx
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #15 on: Thu, 27 Jun 2019 07:13 »
A/T aural? Was this after engine start?

Mark is probably talking about the autopilot wailer?

mark744

  • Join date: Feb 2015
  • Posts: 77
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #16 on: Thu, 27 Jun 2019 07:39 »
Sorry, yes

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #17 on: Thu, 27 Jun 2019 08:54 »
So, in summary:

744: A/P and A/T messages on EICAS
767: (EDIT: Only A/P message on EICAS, but both A/P and A/T on the discrete warning indicators on the main instru. panel

Weird.

See messages below.)
« Last edit: Fri, 28 Jun 2019 07:35 by John H Watson »

Mariano

  • Join date: May 2009
  • Posts: 592
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #18 on: Fri, 28 Jun 2019 07:08 »
Just held (767) A/T Disconnect switch again for ten seconds on the ground with engines shutdown and only EICAS message (and discrete light) activated. No wailer.

Best regards,

Mariano

John H Watson

  • Join date: May 2010
  • Location: On a pedestal
  • Posts: 1986
Re: Preflight test of A/P & A/T disconnect alerts
« Reply #19 on: Fri, 28 Jun 2019 07:34 »
Thanks for checking again, Mariano.

Earlier you said

Quote
Video 3 shows what happened when I pressed and released and then pressed and held the thrust lever A/T Disconnect button. Only the amber A/T DISC discrete light illuminated.

Hence my confusion.