Excuse me, autoflight is complicated and information considering this issue is very fragmented, I am trying to filter and report the relevant bits and pieces related to this specific case not any other mode or CONFIG.
That doesn't mean information is complete.
Whatever the altitude ?
Altitude is not mentioned considering this limit, but pressure information is an input to FMGEC so could be used in the AP command calculations.
Once again is it sure you'll be VLS protected if you're already 40kt below ?
What would be the command ?
It is IMO a scenario not foreseen on the design board.
-No, not for me, AP is disengaged and can not be engaged below VLS.
That's a clear statement!,
Such a statement is not made in the FG section.
AP disengagement doesn't prohibit the FG to calculate FD guidance and display.
-The expected guidance would be LEVEL OFF!? ......and handle speed
(Identical as AP/AT command when VLS is encountered in CLB mode)
-Agreed. but there are different views on how such a scenario was initiated and did developped.
-Thx for correction.
The following snippets concerning AP/FD Speed Protection:
(Read the NOTE: section)
What do they mean with -except level off is performed-?
level off as result of this speed protection or level off due to CRZ?
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Clearing of FD commands
Manual clearance
.....
.....
1// Logic-controlled clearance
a/ Axis-by-axis removal
.......
- NCD on the three labels when the FD ENGD condition is lost
- NCD on label 141 (pitch bar) when no longitudinal mode is engaged or when the ROLL OUT mode is active
- ......
.......
b/ FD disengage request
The FGE requests the FCU to disengage the FD if:- Aircraft speed is not in the flight envelope (VLS, VMO, VFE), and
- The AP is disengaged, and
- The FD is in OPEN CLB/DES or CLB/DES modes
When the FD is disengaged, the A/THR changes to SPEED mode to bring the aircraft speed back in the flight envelope.
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NOTE: AP/FD speed protection
The speed protection is applied, according to the mode, in order to protect against Vmin or theta max (=22.5°) when climbing or Vmax when descending with the following load factor limits:
Max pitch attitude limitation is set to theta max =22.5°
The protected modes are OP CLB, OP DES, CLB, DES, ALT*, and V/S-FPA except when a level off has been performed.
Description of Vmax/Vmin:- 0.3g max versus VMO
- 0.15g max versus VFE or VLE (when landing gear is down).
- Vmax is VMO(MMO)-1kt in clean configuration, VFE/VLE+4kt else
- Vmin is VLS if Vc target >or= VLS +5kt or Vmin is VLS-5kt if Vc target =VLS
Specific indications upon AP speed protection activation in V/S-FPA mode:
With AP engaged, when V/S-FPA target is not held by the AFS because it is excessive, the AP speed protection is activated: a triple click aural indication and a flashing amber box around V/S or FPA mode and target on the FMA are commanded by FMGEC.
Example Speedprotection when AP engaged:
