WPvsMW
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Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 7:54 am

The sidesticks on the Airbii 319/320/321 have a pushbutton, the Takeover pushbutton. The last pilot to press the Takeover pb has priority. How often is the Takeover pb used?
Is it on the larger Airbii?
Do Boeing a/c have an equivalent pb?

Moving the sidestick when on autopilot will disengage the autopilot. Does this ever happen? Is this why it is dangerous to read a newspaper when on autopilot?
 
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Starlionblue
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 8:21 am

330/340/350/380 have the same logic. As far as I can tell the stick is identical.

The takeover pushbutton is pressed every flight since it is also the instinctive disconnect button for the autopilot. ;)

I've never seen the pushbutton used for takeover except in the simulator. The functionality is there for stick malfunctions, incapacitation situations or if one pilot feels the other one is about to do something really silly and must take over immediately.

Boeing's equivalent is the decoupling of the yokes if enough force is applied.

The sidestick is locked when the autopilot is engaged so it is pretty hard to move. If you lightly bump it by mistake it'll just stay in place. I've never seen the autopilot disengage due to force applied. If you accidentally bump the instinctive disconnect pushbutton with your knee (been there, done that) the autopilot will disconnect, with associated aural and visual warning. but all you need to do is look up sheepishly and then re-engage the autopilot.

It's not dangerous to read the newspaper, or study material, or whatever during the cruise, as long as you take certain precautions. Don't hold your reading material in a way that obscures the instruments, and ensure your attention is somewhat on the instruments (and the speakers) in order to catch messages and such. Of course, if you're dodging thunderstorms maybe pay attention to that instead of the paper. Judge the situation and manage your distractions accordingly.

Besides, as mentioned, if the autopilot disengages you get aural and visual warnings which are pretty hard to miss. The disconnect warning is LOUD!

Pilots regularly have cruise phases that last from 1 to 16 hours. It would be unrealistic to expect us to sit and stare attentively at the instruments while doing nothing else the entire time we are in the seat.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
WPvsMW
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 9:16 am

Starlionblue... your posts are always informative, and I'm glad you construed my newspaper comment in the humorous way intended. I know a cargo captain who writes novels in the left seat during the long stretches on autopilot. As you observe, no reason not to multitask when the a/c doesn't need attention. Much safer than zoning out from boredom.
 
flipdewaf
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 9:41 am

Starlionblue wrote:
Boeing's equivalent is the decoupling of the yokes if enough force is applied.
Is that like when I opened my lap top with too much force and the screen "decoupled"?

Being serious for a second though... if, for example, on a Boeing, the FO was pushing and the Capt. was pulling and the "decouple" happened and the FO has stick fully forward and the Capt fully back then what would the aircraft be commanded (in the case of the FBW aircraft) orwhat would the control surfaces do (in the case of a non FBW aircraft)?

I realise you are an airbus driver but maybe you know or someone else on here would have the knowledge.

Thanks,

Fred
Image
 
WPvsMW
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 10:06 am

I think Boeing, like Airbus, a/c would have a bright visual, and a loud audio, "Dual Input" warning. As to who wins the tug of war... that needs a Boeing a/c pilot who's just prepped for the simulator. :smile:
 
WIederling
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 12:48 pm

flipdewaf wrote:
Starlionblue wrote:
Boeing's equivalent is the decoupling of the yokes if enough force is applied.
Is that like when I opened my lap top with too much force and the screen "decoupled"?


If you can fit it back together as designed without glue later on? YES.

IMU the split goes back over the redundant pathes to separate control surfaces ( but same function )

i.e. you should have similar behaviour to the competing input on Airbus FBW ( while mixing is at the tail so to speak
and not at the stick input processing level)
The override function "press button" should not be available with split joke input?
Murphy is an optimist
 
Flow2706
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 3:04 pm

The decoupling mechanism is installed in a lot of aircraft type. As I fly Airbus I do not have any personal experience with this kind of device (concerning the Take Over Pushbutton: I have never had to use it and I haven't flown with anybody who ever used it...), but I read an incident report where an ATR almost experienced a structural failure of the tailplane (which would have had catastrophic consequences) due to inadvertent operation of this mechanism at high speed with a lot of force - the aerodynamic loads almost ripped the stabilizer apart. You can find the report here (its still an interim report, I'm not sure if the final report was released until now..): http://www.atsb.gov.au/media/5772731/ao ... report.pdf
 
WPvsMW
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Re: Last pilot to press Takeover pb has priority

Fri Dec 01, 2017 6:27 pm

Very interesting report from the ATSB, with interim conclusions confirmed by UK AAIB. There's no time scale on the graphs, but I assume each vertical line is one second, so all hell broke loose 4 seconds after decoupling.

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