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Saab 340, setting VS and heading


gunner
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I have searched through the manuals trying to find how to change the VS and heading settings while using the autopilot. For the life of me, I can't find the information. I know it must be there and the process must be simple, but I have to admit I am at a loss as to where it is. Any help would be appreciated.  Thanks.

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gunner,

 

It is a bit tricky at first and a bit unwieldily because of the position in the cockpit of the MSP, APA (altitude selector), the pitch-wheel (center console) ,and the EADI reading. I have a view set in my cockpit that shows all 4 at once as zoomed in as possible.

 

1. initial climbset target altitude on the APA; use the low, medium, or high IAS setting by just clicking the the CLIMB button until you see the desired VS on the EADI (personally I use the 141 IAS until 10000)

2. enroute climbs: set target altitude on the APA, then press the VS button on the MSP (yellow light), rotate the pitch-wheel down (down arrow), and watching the EADI, wait until the desire vertical speed is showing and then quickly release the wheel (increase power)

3. descent: set target altitude on the APA, then press the VS button on the MSP (yellow light), rotate the pitch-wheel up (i[ arrow), and watching the EADI, wait until the desire vertical speed is showing and then quickly release the wheel (I reduce power)

 

Make sense? If it doesn't work, chances are you forgot to set your target altitude.

 

Brad

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2. enroute climbs: set target altitude on the APA, then press the VS button on the MSP (yellow light), rotate the pitch-wheel down (down arrow), and watching the EADI, wait until the desire vertical speed is showing and then quickly release the wheel (increase power)

 

 

for climb is best and safer to use IAS mode, you select your desired climb speed rotating the speed bug and the AP will accommodate the VS rate continuously to guarantee your desired IAS speed during the entire climb. The higher you go the lower the VS rate would result to maintain the speed.

 

It is a bad idea to use VS for climbs abobe 10000, because in this mode the aircraft AP will guarantee the ascend rate and the IAS will drop rapidly while climbing, the IAS will also vary a lot based on existing weather conditions (temp/winds/pressure). As consequence climbing in VS will result in constant manual intervention or you risk to stall the aircraft.

 

I would advice to use IAS mode to climb except for initial after takeoff CLIMB mode.

Edited by mmerelles
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  • 3 years later...

I also have problems to figure this out.

I can set with vert_sync and this is the only way available to me right now. But it sure must be possible to set vert directly and more precise.

In the tutorial I find information what I have to do but it does not say how, like

"Reset your altitude on the APA to 3,000 feet and set your vertical speed to descend at a rate of 1300fpm"

 

 

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What makes this even harder for me is that before I can hit v_sync VS disengages by itself all the time and I have to hold the stick with my left hand while clicking it again, at which point my desired vertical speed has gone (unless I learn to fly left handed) And often I need to change target altitude too or VS wont engage at all.

As it is I am already happy if I get the autopilot to descend at all.

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The knob in the center pedestal next to the autopilot controls has two functions.
Outer ring is heading, duplicate of the actual HDG knob up with the course ones.
In the middle on top of it is the pitch wheel, has a ridged appearance to it. That controls the VS setting.

Only because you mentioned target altitude, you can't be maintaining a level with that level in the APA.
Great trick in the circuit to forget to reset the APA, attempt to descend by pushing the VS wheel over and watch absolutely nothing happen -_-

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