TOGA Lock on during climb

[chumley 9]

Today I took off and over rotated causing the aircraft to go almost to a stall condition. The climbout came back under control and when the Climb thrust was commanded I duly rolled back the Thrust lever. The detent was found but the indication showed as TOGA all the way to cruise altitude and when the aircraft levelled out it remained locked in TOGA. To correct the indication I had to disengage the Auto Thrust then reengage at which point the indication changed to MACH and the thrust wound back.

Is something amiss here or did I stuff up ( I expect it to be the latter )

Thanks

Andy b

[Chris0410 3]

I had the same problem today. I set climb thrust on the initial climb, the airbus went for a 30 degrees climb near stall, then I saw that there was the TOGA indication. I pulled back the thrust lever completely, then pull it forward and after 2 tries I could manage to set Climb thrust later auto speed.

I never experienced this Problem with 1.10.

Today I took off and over rotated causing the aircraft to go almost to a stall condition. The climbout came back under control and when the Climb thrust was commanded I duly rolled back the Thrust lever. The detent was found but the indication showed as TOGA all the way to cruise altitude and when the aircraft levelled out it remained locked in TOGA. To correct the indication I had to disengage the Auto Thrust then reengage at which point the indication changed to MACH and the thrust wound back.

Is something amiss here or did I stuff up ( I expect it to be the latter )

Thanks

Andy b

[Joshua Che. 1601]

Some screenshots along with more detailed information (steps to reproduce incl dep apt and sid) would be good.

[Chris0410 3]

Joshua I will try to do the same flight again and recreate the problem with some screenshots.

I was flying EGLL from RWY 09L, via SID BUZA3K to WOBUN WELIN T420 TNT EGCC

I started with Cold and Dark and let the Pilot and Co-Pilot do everything by their own.

Some screenshots along with more detailed information (steps to reproduce incl dep apt and sid) would be good.

[Cheyenne Chief Pilot 829]

Pls. check whether thrust mode remains in TOGA or whether it's actually TOGA LK. TOGA LK is a mode that engages after stall protection has been activated (ALPHA FLOOR). As soon as you leave the stall area TOGA becomes LocKed (TOGA LK) - like in the real Airbus.

So screenshots from the PFD (including the FMA) are appreciated.

[chumley 9]

In my case it was TOGA LK.

Andy b

[Cheyenne Chief Pilot 829]

In my case it was TOGA LK.

Andy b

So the AAX successfully prevented for you to fall out of the sky!

Manually disabling A/T and re-engaging it again is standard RW procedure to get back from TOGA LK to CLB - well done, Andy!

[Chris0410 3]

It was TOGA LK for me to.

Thanks for the first explanations. This helped me, to understand more waht's going on. So, the question is changing from "Why TOGA LK" to "Why is the climb in autopilot-mode so steep, that the Airbus is going to stall"?

I will do another test flight first. After that perhaps I can give more Information.

[Emi 5161]

It was TOGA LK for me to.

Thanks for the first explanations. This helped me, to understand more waht's going on. So, the question is changing from "Why TOGA LK" to "Why is the climb in autopilot-mode so steep, that the Airbus is going to stall"?

I will do another test flight first. After that perhaps I can give more Information.

When do you activate the autopilot?

[chumley 9]

Hi

I have just traced my excessive climb out rate which caused the Alpha Floor engagement to a poor stick calibration. After resetting I have been able to avoid the Alpha Floor and thus far everything appears to be operating as per expectations.

In my case autopilot is engaged after thrust reduction during climb out.

Thanks

Andy b

[JustanotherPilot 14]

I too experience a steep climb after engaging auto pilot(ver 1.15), the airspeed doesn't go above 180kts at 30deg climb. I disengange autopilot and autothrottle, lower the nose, build up the airspeed to 200kts, engage autopilot and autothrottle - back to 30deg climb and 180kts. I notice too that the Capt/FO don't retract flaps anymore like in ver 1.10.

For me to get a climb speed I have to manually enter a speed in the speed window. I seem to have lost any auto manged speed or auto throttle with ver 1.15.

For you info I engage autopilot between 700-1000' agl after rotation

[lonewulf47 83]

The answer to this phenomenon is very simple: if someone of the dev team would look into the values of V ls and V alpha prot against V2 you would notice that one or more values are simply wrong. The speed target for V2 is in almost all cases (at least in the A321) within V alpha prot and thus also within V ls which is by definition wrong. As an intermediate solution I would however not recommend a setting of 250 KTS just to prevent this. Just increase V2 by approx.10 KTS in the PERF PAGE and rotate a bit slower. That will do. If you leave SRS upon initial climb out you of course lose all "close in" speed constraints.

Oskar

[Joshua Che. 1601]

The answer to this phenomenon is very simple: if someone of the dev team would look into the values of V ls and V alpha prot against V2 you would notice that one or more values are simply wrong. The speed target for V2 is in almost all cases (at least in the A321) within V alpha prot and thus also within V ls which is by definition wrong. As an intermediate solution I would however not recommend a setting of 250 KTS just to prevent this. Just increase V2 by approx.10 KTS in the PERF PAGE and rotate a bit slower. That will do. If you leave SRS upon initial climb out you of course lose all "close in" speed constraints.

Oskar

Interim solution until this is fixed: Before engaging the AP switch from managed to selected speed and dail in 250kts. Thereafter engage the AP and once 250kts have been reached switch to managed speed again.

Lets wait for further screenshots from the user before making judgement.....

Right now the situation is still very unclear to me. (when it exactly happened etc)

[lonewulf47 83]

There's no mystery in the whole story. First of all SRS must hold V2 +10, no matter at which speed lift-off has occurred. In case of EO sensed it must hold V2+10 or speed at lift-off, whichever is higher. That's according to FCOM 1.22.30. The present V-speeds seem adequate however the values of V LS and V ALPHA PROT are much too high (V LS should be indicated 10 sec. after lift-off however not visible as it is obviously buried within V ALPHA PROT). The overall AoA seems pretty high. Unfortunately there are no values for V LS etc. published in the FCOM. This might need some spot verifications within a real world A/C or Simulator, especially also regarding actual AoA. This can easily be done with simultaneously using FD and FPV. the difference between actual pitch and FPV angle is the AoA.

The maintained speed by SRS must be well clear of V LS !

So as a consequence: critical speeds and SRS must definitely be reviewed on all models. A321 seems to be more prone to TOGA LOCK however I have seen it also on the A320.

Oskar

[Joshua Che. 1601]

There's no mystery in the whole story. First of all SRS must hold V2 +10, no matter at which speed lift-off has occurred. In case of EO sensed it must hold V2+10 or speed at lift-off, whichever is higher. That's according to FCOM 1.22.30. The present V-speeds seem adequate however the values of V LS and V ALPHA PROT are much too high (V LS should be indicated 10 sec. after lift-off however not visible as it is obviously buried within V ALPHA PROT). The overall AoA seems pretty high. Unfortunately there are no values for V LS etc. published in the FCOM. This might need some spot verifications within a real world A/C or Simulator, especially also regarding actual AoA. This can easily be done with simultaneously using FD and FPV. the difference between those two is the AoA.

The maintained speed by SRS must be well clear of V LS !

So as a consequence: critical speeds and SRS must definitely be reviewed on all models. A321 seems to be more prone to TOGA LOCK however I have seen it also on the A320.

Oskar

Oskar,

I am well aware of how SRS works and how it should behave. I am looking into the cause of the issue now.

[lonewulf47 83]

In the MCDU you can call up the actual AoA as well.

Interesting! Can you give me a hint where and how to call it up? That would make things much easier. Or do you refer to the RW MCDU? I see an AoA of approx. 8-9° which indeed could be close for V2 + 10.

Oskar

[lonewulf47 83]

I'm talking about RW.

Lovely...

[Joshua Che. 1601]

Corrected a small PFD VS1G Stall calculation error. Should solve some of the issues here, but not all.

[cgentil 163]

Corrected a small PFD VS1G Stall calculation error. Should solve some of the issues here, but not all.

Will be released in hotfix shortly?

[Cheyenne Chief Pilot 829]

Since Joshua "forgot" to include the download link ... ( ):

In the A321 I engage A/P with SPD managed and, immediately after A/P engagement, I select/pull SPD and dial ("wheel") it up some 10-20 kts.

[Neo444 0]

Maybe you forgot to set the Take-Off trim? If you forget that it will get into alpha Floor and TOGAKL mode. If you set the trim before take off, it won't.