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Cessna 172 AP Nav not working with cold start

Featured Replies

Hi,

Have you noticed that the AP, at least in Cessna 172, doesn't work after cold start (if you begin with your Cessna parked and engines off). 

However, if the plane is placed directly on the runway with the engine running, the autopilot in NAV mode works.

I don't understand why.

 

  • Author
8 minutes ago, Armchair Pilot said:

Have you tried checking the cdi source is set correctly? 

No, but on the same same airport, the same flight plan, and if I start in cold star there is no possible way to put the AP in NAV. However, if I put the plane in the runway with the engine running it always works. Every time I try it's the same! Simply I don't understand it.

 

 

 

Edited by John Fields

47 minutes ago, John Fields said:

No, but on the same same airport, the same flight plan, and if I start in cold star there is no possible way to put the AP in NAV. However, if I put the plane in the runway with the engine running it always works. Every time I try it's the same! Simply I don't understand it.

 

 

 

Thats because the system is preselecting your cdi source. 

Armchair Pilot is exactly right. I've experienced the same thing with the Longitude, when it wouldn't follow the flight plan after a cold start. I then realized that the CDI wasn't set "correctly."

Processor: Intel i9-13900KF 5.8GHz 24-Core, Graphics Processor: Nvidia RTX 4090 24GB GDDR6, System Memory: 64GB High Performance DDR5 SDRAM 5600MHz, Operating System: Windows 11 Home Edition, Motherboard: Gigabyte Z790 Aorus Elite AX, LGA 1700, CPU Cooling: Corsair H100i Elite 240mm Liquid Cooling, RGB and LCD Display, Chassis Fans: Corsair Low Decibel, Addressable RGB Fans, Power Supply: Corsair HX1000i Fully Modular Ultra-Low-Noise Platinum ATX 1000 Watt, Primary Storage: 2TB Samsung Gen 4 NVMe SSD, Secondary Storage: 1TB Samsung Gen 4 NVMe SSD, VR Headset: Meta Quest 2, Primary Display: SONY 4K Bravia 75-inch, 2nd Display: SONY 4K Bravia 43-inch, 3rd Display: Vizio 28-inch, 1920x1080. Controller: Xbox Controller attached to PC via USB.

I confirm John.  The A/P works when you start the Skyhawk C&D.

Dominique

Simming since 1981 -  [email protected] GHz with 16 GB of RAM and a 1080 with 8 GB VRAM running a 27" @ 2560*1440 - Windows 10 - Warthog HOTAS - MFG pedals - MSFS Standard version with Steam

 

  • Author

Hi,

Thank you all for your help.

I'll try to set the CDI this afternoon (although I don't how to do it yet).

 

  • Author

Hi,

It works like a charm!

And it's very easy to set the CDI.

Thank you again for your help!

Edited by John Fields

1 hour ago, John Fields said:

Hi,

It works like a charm!

And it's very easy to set the CDI.

Thank you again for your help!

You've been flying this plane for 6 months and now just figured out how to set the cdi? 🤦🏿‍♂️ 

  • Author

Hi,

Yes, because I didn't fly the C172!

I used the C152 instead, and also the Savage Carbon (this one, very very much) and also one or two small aircrafts (but not so much). All of them without AP.

I usually do bush flying with very short flights, that's why.

But I'm going to try some other aircrafts. Some day! 😃

I've never tried the Daher tbm (so popular among msfs pilots) or airlines (I don't think I couldn't, because I consider these planes a bit too complicated for me). 

Greetings

🙂

 

 

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