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dromeascr

A couple of general questions about NGX

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Hello simmers, I'm new in the NGX and now I'm trying to learn how things work here (I'm used in the PMDG 777). Always have in mind that I have many flight hours in the 777 when answering the below. And please do not simply say "Refer to the manual", because I already did. (I have read the entire tutorial 1 from Gatwick to Schiphol)

 

So:

1. Do the weather and the terrain radars function in the PMDG 737 NGX? (Are they modelled?). I'm using ASN (In the PMDG 777 the WXR requires ASN in order to work). So far I haven't seen any terrain/cloud traces on the ND. So, are they?

 

2. What's the Gear's lever middle position, (It says "off" next to it), and when should I put the lever in the middle position?

 

3. What's the purpose of 2 CMD buttons. 

 

4. Is there a way to autotune to the nearest VORs as I cruise? 

 

5. Can I set a speed restriction in the FMC? (especially during the descent). In the 777 it could be done in the VNAV 3/3 page. Here, by going in the DES page, there's only the global 240/10000 restriction and I can't put my own one somewhere. 

 

6. What's the function of the CWS buttons in the MCP (next to the CMDs).

 

Thanks in advance.

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Hello!

 

1. Yes (provided you have the latest version -- SP1d IIRC). Ground returns are not modelled as far as I know and remember that the radar shows you precipitation, not clouds.

 

2. "Off" removes the hydraulic pressure from the gear (and it is then held up by mechanical uplocks). When you place the gear lever to OFF will depend to an extent on airline procedures, but generally after takeoff and immediately following flap retraction.

 

3. Two separate autopilot systems, powered by different buses and using different hydraulic systems (mostly -- I don't know the specifics of the 737 system). In normal operations you would only use one (usually depending on who's flying -- so if the Captain is PF they would generally use A whereas the FO might use B, but the outcome will be exactly the same). You would engage both on approach as both are required for an autoland (redundancy). Some airline SOPs have you engage both autopilots for all approaches (even if you're planning to disconnect and land manually) as I think this gives you automatic go-around capability in the 737 -- others only require both autopilots to be engaged if you're planning to do an autoland (I think the 737 gives you a bunch of back trim at around 500ft as part of the autoland process, so if you disconnect after this you'll be handed an aeroplane that's out of trim). The 777 has three autopilots, but the way they operate is transparent to the pilots (so only one CMD button).

 

4. No.

 

5. I don't think so (different FMC capability), but again I'm not an expert on the 737 systems. I think you might have to give it both a speed AND an altitude at a particular leg.

 

6. CWS stands for Control Wheel Steering. In very basic terms, you point the aeroplane where you want it with the yoke and the autopilot trims to maintain the attitude (it might be more nuanced than that, but IIRC that's the basic result). Some people love it, some people hate it, I don't think it's particularly commonly used.

 

Hope that helps!

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Sure does, thanks.

 

 


1. Yes (provided you have the latest version -- SP1d IIRC). Ground returns are not modelled as far as I know and remember that the radar shows you precipitation, not clouds.

So, the WXR is modelled while the Terrain radar is not.

 

About CWS, I just don't get how the wheel steering has to do with the attitude,  other than that it was as helpful as it could. 

 

Best Regards

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Sure does, thanks.

 

So, the WXR is modelled while the Terrain radar is not.

 

About CWS, I just don't get how the wheel steering has to do with the attitude, other than that it was as helpful as it could.

 

Best Regards

The latest PMDG NGX has both weather radar and terrain mapping. It has always had EGPWS terrain. The weather radar was added in an update within the last year.

 

The terrain map is not a "radar" - either in the sim, or the real aircraft. The system contains a digital model of the surface elevation for the entire world - (rather similar to the mesh found in flight simulators in fact), and uses the aircraft's current GPS position, altitude, heading and rate of climb and descent to determine what terrain (and in what color) to display.

 

CWS allows the pilot to override the autopilot to steer the aircraft in pitch or roll with the yoke, WITHOUT disconnecting the autopilot.

 

Ordinarily, if the autopilot is engaged, and the pilot tries to manually turns the yoke in roll, or push or pull it in pitch, it would require quite a bit of force, and would cause the autopilot to disconnect. If the pilot pushes the CWS button, the autopilot releases its control of the yoke, but remains engaged in the background. The pilot can then steer the aircraft manually. This is usually done to make minor pitch and heading changes. When the CWS is turned off, the autopilot resumes control, holding the new heading and pitch.

 

As for number 4, the NG does auto tune, but it is not visible. The aircraft has a pair of dual channel DMEs. The primary DMEs remain linked to whatever VORs are tuned on the NAV 1 and NAV 2 control heads. The secondary channels of the two DMEs are continuously auto tuned in the background to get DME/DME distance cross fixes to keep the IRS position updated.

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Regarding number 5, I'm pretty sure you can change the descent speed in the FMC. I usually just do things old school though and override with the MCP.

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My suggestion, with all your questions, is to do the 2 tutorial flights that come with the 737. It will answer all your questions and you will really learn to fly the aircraft properly. 

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