Auto flight- IAS and NAV modes- question....

[brucek 38]

Loving this aircraft and it’s immersion into flight dynamics! I’ve looked at the included manuals, and the am going through the Tutorial v2 also at the moment, but can’t find the answers to these issues (both relate to the AP):

 

 

1. IAS Mode: I understand what this is, and I have used it to change climb pitch according to the speed that I am requesting. But I’m guessing at the target speed by trial and error- is there somewhere that the commanded IAS (knots) is shown? I would have expected on the PFD, but can’t see it there.

 

 

2. NAV Mode: In the tutorial (v2), I depart and engage the AP to HDG, then change the Heading knob as the tutorial calls for. I then do the :Direct To” on the FMS (no issues here, I can see the active leg), but getting the AP to slave to the FMS flight plan is a chore. On the AP (AFCS?) panel, if I select “NAV”, nothing happens, I remain in HDG mode (as shown on the PFD). I’ve even tried changing the a/c heading to an legitimate intercept heading to the active leg (less than 30 degrees), and tried even pressing the “NAV” button on the FMS (which I think is unrelated), but am never able to get the NAV mode to activate. I did note a message on the FMS at the start of flight plan entry regarding GPS integrity, so it may be that there’s a part of this issue that relates to a basic nav feature (such as INS, or the GPS not turned on, or something) that I haven’t done.

 

 

Thanks, any help most appreciated…

 

Bruce.

[ckyliu 1,749]

In relation to 1):
When you press IAS on the MCP, the autopilot stores your speed at that precise moment as the target speed, and displays it in the top right of the PFD. You can adjust the IAS target by using the wheel in the center of the MCP<br />

In relation to 2):
The GPS integrity message is normal, it's because RAIM isn't simulated as mentioned in the documentation. If NAV mode won't arm, the first thing is to ensure you have selected "purple needles" on the PFD, i.e. the AP nav source is set to FMS1. You can change this by turning the NAV SOURCE knob on the top left of the MCP, the selected NAV source is indicated to the right of the EHSI.

[brucek 38]

Thanks- I had been adjusting the V/S knob on the AP panel, which seemed to have the same effect as I would have expected- I’ll look at the MCP for a speed function, and also at the top-right of the PFD.

 

"If NAV mode won't arm, the first thing is to ensure you have selected "purple needles" on the PFD, i.e. the AP nav source is set to FMS1"

 

OK- this must be my issue, I had not seen this..... at least I know what I am looking for now. Thaks so much for the helpful reply.

 

Bruce.

 

 

Thanks, Bruce.

 

[ckyliu 1,749]

 I had been adjusting the V/S knob on the AP panel..  I’ll look at the MCP for a speed function

They are one and the same, the function of the wheel changes depending on the vertical mode that is selected. The wheel is labelled "NOSE DN" and "NOSE UP" and in the centre of the glareshield on the MCP.