A320 OP CLB behaviour

[vilas]

The following information was released by Airbus in Sochi crash investigation:
The logic of integration of the autopilot/flight director (AP/FD) pitch control and the
autothrust control
¬If AP/FD pitch mode controls a vertical trajectory (e.g. V/S, ALT), then AT controls speed.
¬If AP/FD pitch mode controls a speed (e.g. OP CLB), then AT controls thrust.
¬If no AP/FD pitch mode is engaged, then АТ controls speed.
Logic sequence of the OPEN CLB mode
¬for level change more than 1200 ft:
¬at OPEN CLB mode engagement by the pilot, V/S control with V/S target = +8000 ft/min (40 m/s) is applied for AP/FD, and SPEED/MACH mode is engaged for AT
¬when engine N1 reaches 95% N1CLB mode, AP/FD switches to SPEED/MACH control law, whereas AT switches to the THRUST mode
¬Throughout this time the FMA displays THR CLB for AT and OP CLB for AP/FD
The given scheme of engagement for the OPEN CLB mode ensures the uniformity of the aircraft response in all configurations and within the whole range of the flight altitudes and speeds.
¬For level change less than 1200 ft:
¬at OPEN CLB mode engagement by the pilot, V/S control with V/S target = + 1000 ft/min (5 m/s) is applied for AP/FD, and SPEED/MACH mode is engaged for AT
¬ Throughout this time FMA displays THR CLB for AT and OP CLB for AP/FD
In this case the climb is in fact performed in the vertical speed control mode.
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It should also be noted that if the OPEN CLB mode is engaged less than 30 seconds after the aircraft level off function is activated, the autopilot is authorized to use the vertical acceleration at the maximum value of 0.3g, whereas usually it is only 0.15g.