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How to set altitude in autopilot JS 4100

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HelloMy full name is Aidan Vincent Bartley. There is probably somewhere else to put that but I cannot find it. No doubt someone will tell me.Can someone please tell me how to set the altitude in Autopilot - I'm not using the FMS - I cannot get the alt to change to my setting.ThanksAidan Vincent Bartley (Mr)


Aidan Bartley

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Guest BlueRidgeDx

Aidan,There is a large "ALT" knob on the right-hand Instrument Remote Controller. It's on the glareshield to the right of the TAT/TAS display. Give it a spin.EDIT: I think you might be asking a different question than the one I answered. To get the airplane actually climb/descend to your selected altitude, you need to press the ALTSEL button on the FD panel. Then you need to engage a vertical mode of the FD...Either press VS and then rotate the thumbwheel (on the center pedestal) in the desired direction. Or press IAS and GENTLY rotate the thumbwheel to set the desired climb/descend airspeed. In both cases, you retain control of the power levers, and in IAS mode what you do with them will dictate whether the airplane will climb or descend to maintain the selected speed. In IAS mode, the airplane doesn't care whether your preselected altitude is above or below you, and it will use pitch attitude to achieve the desired speed regardless if it results in a climb or a descent.

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Thanks for the reply Nick. Sorry I should have been more specific. I set the ALT to 5000 but the A/P took it up to 3000 and stopped. On the next flight I set the ALT to 5000 and the A/p just kept it rising past 8000. What are the ALT and ALt Sel buttons for please? The manuals are really assuming I should know and I'm deeply stupid.My question should have read, What is the procedure for setting the ALT when not using the FMC?RegardsAidan Vincent Bartley


Aidan Bartley

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Guest BlueRidgeDx

Aidan,Hopefully my edit answered most of your question. I thought I might have misunderstood...The difference between the ALT button and the ALTSEL button is important.ALTSEL arms the preselected altitude for capture. If you engage a vertical mode but forget to press ALTSEL, the AP will fly right through your selected altitude.The ALT button commands the FD (and thus the AP) to maintain the altitude at the instant you pressed the ALT button. There are a few caveats if your ascent/descent rate was very high at the time of engagement, but thats the basic premise.

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Thanks Nick Am really grateful - I'll give that a bash!Kind regardsAidan (Bartley)Nick - just tried your suggestions and they all worked - thanks for your clear instructions. Now I can fly the plane in a basic fashion, time to try the FSM - my first time with any FSM!RegardsAidan (Bartley)


Aidan Bartley

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Guest BlueRidgeDx

No problem! Glad you got it sorted out.Enjoy!

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