IAS rather than VS on inital AP button push

[carlp101]

Hi,

I'd like the option to be able to select either IAS or VS to be maintained when the the AP button is pushed for the first time. Perhaps on one of the auto pilot set-up screens.

The fact that it currently tries to maintain VS is much more risky just after take-off than trying to maintain IAS.

Thanks
Carl

 

[dynonsupport]

Can you explain why VS is more risky? VS inherently gives you a positive rate of climb, while IAS will descend if the requested IAS is too high or power is too low.

If you are concerned about a stall, the AP is already low airspeed protected if the VS requested cannot be maintained.

Also, what is your definition of "the first time?"

 

[Ccandrews]

Hi,

I'd like the option to be able to select either IAS or VS to be maintained when the the AP button is pushed for the first time. Perhaps on one of the auto pilot set-up screens.

The fact that it currently tries to maintain VS is much more risky just after take-off than trying to maintain IAS.

Thanks
Carl

Carl, I don’t know about ‘safer’, but my preferences for climb are to maintain Vx, Vy, or cruise climb rather than VS.

The initial press of the AP (to engage) is just a pitch and roll HOLD. when you press the AP button the VS bug is just set to the current VS and the AP goes into VS pitch mode.

What I do is to pitch for the target IAS, then press AP and then immediately press IAS. the IAS bug will be set to the present value and the VS pitch control changes to IAS mode. I have had the AP take me up to my airplanes service ceiling at cruise climb without further management or tweaking along the way.

this all presumes you have the AP in expert, I don’t believe that simplified menu has an IAS pitch mode.