Just a few random questions.

• What does the "FCM/COMM" button do on the FCM?  
• Are there any guides to using the HUD?   I thought I saw an FCM page related to the HUD as well (not 100% sure), if so, what are the features on that page?   
• Do the iFly liveries include airline specific equipment, such as a HUD, various optional features, etc?  Or do you have to do the research and then go through the EFB settings and add / delete whatever is needed for a specific airline? 
• I'm having some issues with GSX.   When I request fuel, the truck shows up and is there for at most a minute or two before it drives off.   Does it also connect it's hoses to the fueling port (like the Fenix does)? 
• Do RL pilots turn on the runway landing & taxi lights as soon as the lower the landing gear or can you simply turn the switches on earlier and the lights illuminate upon gear extension?  I have a habit of forgetting to turn on those lights during the landing process.   Same for turning them off during the takeoff process - are the lights turned off immediately upon gear retraction or a bit later when the cockpit is cleaned up post-take-off?  Are runway turnoff lights always illuminated during takeoff / landing?
• When running the APU on the ground, do you need one of the fuel pumps on or is the fuel system designed to automatically feed the APU?
• I selected Cut Back as part of the take-off process but unlike PMDG, I don't really see any reduction in thrust when passing 1,500', nor do I hear the engines throttling back.   Is this accurate? 

Any info is much appreciated 

It might help to specify whether you’re using MSFS 2024 or 2020. Like liveries for 2024 are extremely limited. And liveries will not cover EFB options  

I’m no expert, but as far as the APU goes, I think you need one of the fuel pumps on for it to fire up. 

Edited August 11, 2025Aug 11 by Virtual-Chris

4 hours ago, 11bee said:

What does the "FCM/COMM" button do on the FCM?  

Changes between FMC and datalink/CPDLC functionality.  Except the ATC button does that as well 😉.  Basically, different levels of datalink features have been cobbled into the box at different times in different ways, and varying versions of them are used by different operators.  All a moot point in the sim.

 

4 hours ago, 11bee said:

Are there any guides to using the HUD?   I thought I saw an FCM page related to the HUD as well (not 100% sure), if so, what are the features on that page?   

I keep threatening to make a video tutorial.  One day lol.  Yes, there is an HGS page in the MCDU (not really the FMC, that's just one computer you can interface with using the MCDU.). This page replaces the HGS control panel on the center pedestal of the NG.  You use it to enter runway and glidepath information, and to select various modes of the HGS.  It's all modeled well in the iFly.

4 hours ago, 11bee said:

Do RL pilots turn on the runway landing & taxi lights as soon as the lower the landing gear or can you simply turn the switches on earlier and the lights illuminate upon gear extension?  I have a habit of forgetting to turn on those lights during the landing process.   Same for turning them off during the takeoff process - are the lights turned off immediately upon gear retraction or a bit later when the cockpit is cleaned up post-take-off?  Are runway turnoff lights always illuminated during takeoff / landing?

Somewhat operator dependent but I'll tell you what we do:  taxi light on for motion, turnoff lights on for line up and wait, landing lights on and taxi light off when cleared for takeoff.  Landing and turnoff lights off at 18,000ft.  On the way down, landing, turnoff, and wing lights on at 18k.  Taxi light on when cleared to land. 

Everything on when crossing a runway. 

4 hours ago, 11bee said:

When running the APU on the ground, do you need one of the fuel pumps on or is the fuel system designed to automatically feed the APU?

Yes, but all the fuel pumps are AC powered.  Thus, if you're performing a battery start of the APU (no ground power), the APU will have to suction feed until it's running and you can get the gen on the AC buses.  So, yes, it suction feeds fine... But give it a fuel pump when you can, it's less wear.

I'm not sure I've ever tried cutback in the iFly.  Regular thrust reduction works correctly.  I think there's an option related to cutback in the EFB; might make sure that's selected correctly.

Good questions! Thanks for writing and posting it!!! Some are questions I myself have 🙂

5 hours ago, Stearmandriver said:

Yes, but all the fuel pumps are AC powered.  Thus, if you're performing a battery start of the APU (no ground power), the APU will have to suction feed until it's running and you can get the gen on the AC buses.  So, yes, it suction feeds fine... But give it a fuel pump when you can, it's less wear.

Does it matter which fuel pump/is one in particular used when just the APU is running?

1 hour ago, Tom Wright said:

Does it matter which fuel pump/is one in particular used when just the APU is running?

IIRC left Aft.

22 minutes ago, Sparkrite said:

IIRC left Aft.

Mainly because the left fuel manifold is used.

In the 737-800 you can install a DC powered fuel pump to help if no AC power and only from battery power is used (option)

If no pumps suction from Tank no1 is provided

Michael Moe 

2 hours ago, Tom Wright said:

Does it matter which fuel pump/is one in particular used when just the APU is running?

Functionally, no.  Just one that is correctly plumbed to the APU (so, if a right pump, need the cross feed open.)

1 hour ago, Michael Moe said:

In the 737-800 you can install a DC powered fuel pump to help if no AC power and only from battery power is used (option)

This is an option in any 737, but I don't know of an operator that does it since the APU will suction feed just fine.  Might be useful if you were making a habit of battery starts at particularly high density altitude airports,  but I've done battery starts at Denver on a warm day with no problem.

14 hours ago, Stearmandriver said:

  Landing and turnoff lights off at 18,000ft.

You just gave away your location, FAA boy. 😉

 

In the rest of the world it happens at 10.000ft /FL100.

Well... In *some* of the rest of the world.  And then there are operators that do it at transition, even when below 10k.  Like I said, operator dependent... But it's hard to argue against being more visible when down where GA guys fly.

4 hours ago, Farlis said:

In the rest of the world it happens at 10.000ft /FL100

I used to turn off the extendable landing lights (737 NG) at 10,000 and keep the fixed ones on because the vibration from those extendable lights as you accelerate is a bit annoying. Once you feel them, you can’t “unfeel” them lol

I do the same, though there's no speed limitation on the retractables.  Just a "buzz" in your feet at higher speeds, most noticable for the folks sitting near the wing.  Thankfully most of our fleet that didn't get delivered with the LED arrays has been retrofitted by this point, because the LEDs are SO much better.  The taxi light switch actually does something now 😂.