To cancel ALPHA FLOOR or TOGA LK

[Boroda]

Good time of the day!

According to 320 FCOM to do this "the pilot must disconnect the autothrust", so according to FCOM again (page before) we have two ways, including both levers to idle detent.

But people say:=, that the only way is to use A/THR disconnect p/b.
Is it true? And can I cansel AF while conditions are active for it activation? If can, will it come again?

Thanks a lot.

[Human Factor]

Match the thrust levers to the current power setting (TOGA in this case), press the instinctive disconnect button (the red button on the thrust levers), bring the thrust levers back to the CLB detent, re-engage the autothrust using the button on the FCU. At the same time, reduce the attitude to less than A-prot.

Remember, A-floor and A-prot are independent protections.

[Boroda]

So people are right, FCOM is wrong.
But what about second question please?

[Human Factor]

As I read it, A-floor should be cancelled by using the disconnect pushbutton on either thrust lever. That is the only way to do it. The matching of the thrust lever position to the demanded thrust should be a normal response.

However, if you were to do this with the the thrust levers closed, as far as I know, the aircraft will re-enter A-floor immediately if the conditions for its activation are met.

[mcdhu]

Boroda, why would you wish to cancel the A/Thr while in alpha floor (AF)?

Once you get out of the conditions for AF, you will see TOGA LOCK. Move the TLs back 2 clicks to the Clb gate, cancel the A/Thr using the instinctive Pbs (only one will do), and then press the A/Thr Pb on the FCU and you are back to normal. Always check the FMA to see what the true situation is, FDs back on, you will be in Hdg/VS so now select your way to where you want to be.

I hope this is what you were looking for.

[CONF iture]

I don't think FCOM is wrong, there are effectively 2 ways to disconnect A/THR, the standard and the non standard one, and both do once you're in TOGA LK

can I cancel ALPHA FLOOR while conditions are active for it activation?
I would say no.

At the same time, reduce the attitude to less than A-prot.
Actually to write "At the same time, reduce Angle of Attack to less than ALPHA MAX" would be more appropriate.

Once you get out of the conditions for AF, you will see TOGA LOCK. Move the TLs back 2 clicks to the Clb gate
Maybe you won't get that option as ALPHA FLOOR can be triggered regardless of thrust lever positions.

... When a system brings confusion, is it really better ?
What about simple standard moving thrust levers ...

[Boroda]

Thanks for replies.

I do not want to exit AF, I am just thinking about this FCOM phrase "to cansel AF or TOGA LK thrust, the pilot must disconnect the autothrust" and no more info.

[Max Angle]

When a system brings confusion, is it really better ?
What about simple standard moving thrust levers ...

Quite agree, after 7000+ hours on the Airbus I still think the A/T system is the worst feature of what is in most respects a very good aircraft.

[320 driver]

What's confusing?

Diconnect the A/THR using the instinctive pbs (this will disengage AF or TOGA LK) and set the power or re-engage.

The idle lever option also works but why would you?

[WannabeAirbusFlyer]

Well I was in the sim recently for a six monthly LPC, and we actually tried the same. If you try to disconnect the A/Th. (by depressing either instinctive pushbuttons), while in the Alpha Floor protection range, it will re-deploy Alpha Floor mode immediately, in real time. This is because, as Human Factor said, Alpha Floor and Alpha Prot mutually exclusive protections. The best thing (I would say the ONLY thing, as well as Airbus Industrie would, say) to do should you have an Alpha Floor situation triggered off. Would be to decrease the angle of attack (Alpha) as much as possible, and once the TOGA Lock is displayed on the ECAM, to disconnect the Alpha Floor as per procedure.

What I'm trying to say is that the Alpha Floor protection is exactly what it's called..... a 'PROTECTION' !! Therefore, as long as the aircraft computers think you need it.... USE IT !! once you dont need it any longer, and the aircraft tells you the same, and YOU as handling pilot (with the CM1's approval in case of CM2) feel you do not need TOGA power any longer, disconnect it by all means.

Any of the protections below Vls are paramount to the safety of the flight, and should as such be given their due importance.

[Boroda]

Thanks a lot!
It is what I need. It means that FCOM explanation is not accurate.

[Jonty]

The FCOM is correct.

To disconnect the ATHR in alpha floor press and hold the ATHR disconnect push button for more than 15 seconds. ATHR is now disconnected and is not usable until the next FMGC power up on the ground. FCOM 1.22.30 P63

But please don't!

[VRSCSE2]

The best method to get out of TOGA LOCK after you are out of the Alpha Floor is thrust levers to idle, (this is the disconnect) then select A/THR pb on....then place the thrust levers in the climb detent.
vrsc

[Cardinal]

I fly the Airbus, like it, but the very fact that this thread has grown to 13 replies regarding A/THR disconnection.....means the system could be better and simpler.

[Clandestino]

According to 320 FCOM to do this "the pilot must disconnect the autothrust", so according to FCOM again (page before) we have two ways, including both levers to idle detent.

Four ways, three of which are practical and one of three is easy. 1.22.30 P62 refers.

reduce Angle of Attack to less than ALPHA MAX

How do you get above alpha max in normal law? Human Factor got it right first time.

To disconnect the ATHR in alpha floor press and hold the ATHR disconnect push button for more than 15 seconds

Unnecessary. Dangerous. Don't do that. Press the red button but don't hold it.

I fly the Airbus, like it, but the very fact that this thread has grown to 13 replies regarding A/THR disconnection.....means the system could be better and simpler.

Alternative explanation is that some people just don't RTFM. FCOM could be better, autothrust - I don't think so.

[CONF iture]

Who said "above" Clandestino ?

[Jonty]

Unnecessary. Dangerous. Don't do that. Press the red button but don't hold it.


Stating the obvious!

[Boroda]

I think it would be right to state on the theme only tested things (on simulator or in flight). But thanks anyway for any interest/opinion. Airbus FCOM is too massive and inaccurate in comparence to 737 - it is pity true. Thats why I placed my topic here to find out the truth from real Airbus drivers.