The A310 FCOM says when climbing or descending, you can hit pre-set the cross-over Mach / IAS by:

1. Pushing the speed knob (PRE SET illuminates)

2. Pushing the SPD/MACH button.

3. Setting your desired speed or Mach number.

The plane will either climb at current IAS and switch to the pre-set Mach at the appropriate cross-over altitude, or descend at the current Mach and switch to the pre-set IAS at the appropriate crossover altitude.

Currently, STEP 2 does not work properly in Speed Mode. When climbing using IAS, pushing the speed/mach button when in pre-set mode does not flip the selected speed window to speed or Mach. It stays in Speed.

STEP 1 does not work properly in Mach mode. When descending using Mach, pushing the speed knob forward sets the current selected speed to 000 IAS!!

Note: Currently Pre-Set Speed-Speed transition during ALT* does work according to the FCOM. Just not Mach-Mach or Speed-Mach or Mach-Speed.

Edited January 17, 20233 yr by bear.is.flying

Heya :]

Yep, this is a known issue and already on our radar. Thanks for reporting though ^-^

Hey just a test report, on the most recent SU12 beta version, the Preset Speed-Mach feature still broken. 

On 2/26/2023 at 9:29 AM, bear.is.flying said:

Hey just a test report, on the most recent SU12 beta version, the Preset Speed-Mach feature still broken. 

Yes, this is correct. This item didn't make it into the changelog.