Questions about FMC VNAV setting on PMDG 737

[David Mills 4,739]

I'm totally enjoying my new learning experience with the FMC on the PMDG 737. But I have a few questions for you experts:

* Are you still required to set the altitude with the manual altitude control? I have all my altitude parameters set within the FMC for various waypoints. But I often get an error message during flight at the bottom of the FMC saying that I need to adjust the Altitude control. Do I need to set my maximum altitude manually even though the FMC already has my preferences programmed? Must I manually set a minimum Altitude on the way down? 

* Do you still need to manually tune the ILS frequency -- on the knobs near the throttle -- even though you already told the FMC which runway you were landing on and the FMC shows that your ILS has been selected and has been executed? I never get a clean handoff between the last waypoint near the airport and the ILS landing system. Must I press the Approach Hold button as well even though the FMC already has the ILS information?

 * What does it mean when the FMC tells me I need drag? What should I do?

* Is it possible to enter flap settings into the FMC? I know how to set waypoint speed and altitude, but how do you program the flaps for varying waypoints?

* Should I need to press the Speed button on the panel, or should the FMC control everything? I've enabled the FD, the CM autopilot, LNAV and VNAV. I'm having varying degrees of success with each flight. I'll sometimes get a message saying that the request parameter cannot be achieved.

Many thanks for your help!

 

Edited May 19, 2022 by David Mills

[Stearmandriver 2,240]

2 hours ago, David Mills said:

I'm totally enjoying my new learning experience with the FMC on the PMDG 737. But I have a few questions for you experts:

* Are you still required to set the altitude with the manual altitude control? I have all my altitude parameters set within the FMC for various waypoints. But I often get an error message during flight at the bottom of the FMC saying that I need to adjust the Altitude control. Do I need to set my maximum altitude manually even though the FMC already has my preferences programmed? Must I manually set a minimum Altitude on the way down? 

The flight guidance will always honor the altitude set in the mode control panel window. This is intentional and a standard of airline flight ops.  It provides protection against altitude incursions; an aircraft changing altitude before being cleared to do so. 

* Do you still need to manually tune the ILS frequency -- on the knobs near the throttle -- even though you already told the FMC which runway you were landing on and the FMC shows that your ILS has been selected and has been executed? I never get a clean handoff between the last waypoint near the airport and the ILS landing system. Must I press the Approach Hold button as well even though the FMC already has the ILS information?

Yes, you'll always need to tune the frequency and set the course for an ILS, and arm Approach mode on the MCP.  An ILS is a radio navaid-based approach, vs just using data in the FMC.  You can fly an ILS with nothing entered or initialized in the FMC at all, though it's standard to add the approach in the box for situational awareness and missed approach guidance.  

 * What does it mean when the FMC tells me I need drag? What should I do?

It means you need drag to maintain the FMC's calculated descent path.  You should add some ;).  Speedbrake, flaps or gear (gear is the most effective but usually reserved until relatively close to the airport.)

* Is it possible to enter flap settings into the FMC? I know how to set waypoint speed and altitude, but how do you program the flaps for varying waypoints?

No, you cannot specify a flap setting at a waypoint. You select a landing flap setting in the landing perf page of the FMC, and this is used to calculate your approach speed.  You will see a calculated speed for every waypoint on the Legs page; it's wise to try and fly those or slower. When you're slowed below clean maneuver speed (the "Up" bug), add flaps as appropriate. 

* Should I need to press the Speed button on the panel, or should the FMC control everything? I've enabled the FD, the CM autopilot, LNAV and VNAV. I'm having varying degrees of success with each flight. I'll sometimes get a message saying that the request parameter cannot be achieved.

This is dependent on your vertical flight guidance mode. If you're in VNAV with the speed window closed (the speed window on the MCP blank), the FMC is managing your speed. If you're in a different vertical flight guidance mode, the speed window will be open and you'll need to set the speed you want to fly. 

I recommend running through the tutorial flight step by step; don't skip anything even if you think you know it.  It should clear a lot of this up. 

Many thanks for your help!

 

 

[David Mills 4,739]

Thank you so much, @Stearmandriver. I really really appreciate your expertise and the time you devoted to writing such a helpful and detailed response. I know I'll spend the next few hours practicing your tips.

Much gratitude,

David

 

[Jetman67 517]

2 hours ago, Stearmandriver said:

 

absolutely amazing the support we get from the real professionals, thank you so much

[Jetman67 517]

2 hours ago, David Mills said:

Thank you so much, @Stearmandriver. I really really appreciate your expertise and the time you devoted to writing such a helpful and detailed response. I know I'll spend the next few hours practicing your tips.

Much gratitude,

David

 

Hi David

 

i also recommend videos from 737 NG driver he is also amazing, this 737 is amazing and will only get better. 

(27) 737NG Driver - YouTube

 

Cheers

Wayne

 

 

[Stearmandriver 2,240]

Absolutely, Emi's videos are top knotch.