Christopher Low

First autopilot flight in the 747-400 QOTSII

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I have just attempted my first autopilot controlled flight in the 747-400, and I noted some differences to the 737 NGX (which is to be expected). The 737 NGX seems to automatically enter ALT HOLD mode when reaching cruise altitude, but it seems like I need to press the ALT HLD button on the MCP to switch from VNAV PTH mode to ALT HOLD mode in the 747-400. Is this correct? This is not mentioned in the tutorial....unless I missed it. In addition, do I not need to enter the ILS approach frequency anywhere when preparing for the approach (like I do in the 737 NGX)?

Please don't bite my head off here. I am simply trying to understand (and learn) the differences between the 747 and the 737 :smile:

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No and No...

The aircraft will stay in VNAV PTH in the cruise, there is no need for you to change it.

If you select an ILS approach in the FMC it will automatically tune the ILS for you (but probably worth checking as you get near to your destination).

Hope this helps,

Ian Webber

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Just another difference between the 737 and 747 you'll come across:

The 747 can't do RNAV approaches. It's not equipped for these.

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1 minute ago, RichieFly said:

The 747 can't do RNAV approaches. It's not equipped for these.

A Trashhawk 172 can do RNAV approaches. Are you, perhaps, confusing RNAV and RNAV (RNP)?

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I guess I must have done something else wrong when I approached my destination, as the aircraft failed to lock onto the ILS localiser, and refused to descend unless I "forced" it down with LVL CHG. I will try the same flight again, and see if I can identify the problem.

On a side note, I realised that I had forgotten to activate the V1 callout for the take off (which I have since corrected), but I still do not have the "rotate" and "V2" callouts. How do I get these working?

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59 minutes ago, scandinavian13 said:

A Trashhawk 172 can do RNAV approaches. Are you, perhaps, confusing RNAV and RNAV (RNP)?

Yes. Confusion, I have it.

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19 minutes ago, Christopher Low said:

I guess I must have done something else wrong when I approached my destination, as the aircraft failed to lock onto the ILS localiser, and refused to descend unless I "forced" it down with LVL CHG. I will try the same flight again, and see if I can identify the problem.

Did you check the ILS frequency in the sim? It may be different than the one in the FMC since they are two different nav database and while the nav database of the FMC is updated with the AIRAC, the one of the sim is not.

Most of the time, if a localizer is not captured while the APP is armed and you are on instercept route, you can bet that it is a problem of  frequency mismatch.

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24 minutes ago, Christopher Low said:

but I still do not have the "rotate" and "V2" callouts. How do I get these working?

In the options of the FMC. 

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3 hours ago, Christopher Low said:

On a side note, I realised that I had forgotten to activate the V1 callout for the take off (which I have since corrected), but I still do not have the "rotate" and "V2" callouts. How do I get these working?

From the FMC menu click PMDG Setup > Options > Simulation > Pages 4 and 5 have the PNF callouts. There are options for airspeed, 80 knots, V1 on page 4, and VR, V2, and positive rate on page 5.

 

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10 hours ago, RichieFly said:

The 747 can't do RNAV approaches. It's not equipped for these.

It most certainly can, at least, the real one can, even RNP, I don't know about this model though.

Ian Webber

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If the real aircraft can execute an RNAV approach, then I am certain that the PMDG one can. You do realise that Boeing based the design and technical specifications of the real world 747-400 on the PMDG version? :wink:

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Another question I wanted to ask......

After TO/GA is engaged (and THR REF is displayed on the FD), the tutorial states that I need to increase the throttles to maximum. Not a problem.....but do I need to keep them there for the entire duration of the flight? The reason I ask is because, when I disengage the autopilot on final approach to perform a manual landing, as soon as I touch those throttles the power is going to jump to 100% (unless I can get them to the correct setting by sheer luck). This doesn;t seem to matter in the 737, because that 40% mark before TO/GA is engaged is quite close to the power setting on final approach.

In short, is there a procedure for this?

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56 minutes ago, Christopher Low said:

Not a problem.....but do I need to keep them there for the entire duration of the flight?

Nope. Why would we request that you do that? The "show throttle position" option is there for a reason: it helps you match your throttles up when dumping AT.

In short:

  • IDLE through start
  • Taxi: As required
  • Takeoff: 40-55% (I forget what the tutorial says) and then hit TO/GA; throttles full
  • Before T/D: IDLE
  • Approach: Match and dump off of A/T; then as required
  • Final/Landing/Taxi: As required
  • IDLE before fuel cutoff
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I was almost successful on my second attempt. I say almost because.....although I successfully captured the glideslope, pressing "Z" to disengage the autopilot on final approach did not seem to work. The left hand button of the three "autopilot buttons" remained on, and I was unable to take manual control of the aircraft. I ended up disengaging the autopilot when I tried to force the flare, and the result was that the aircraft pitched up and started to rise again! I did manage to get the plane down and stopped before the end of the runway (by maybe a hundred feet), but that isn't good enough for me, so I will be attempting the same flight again until I get it right.

I noted that to disengage the autopilot properly, I had to click on the large rectangular button below the three "autopilot buttons". I can do that next time, but I had assumed that pressing "Z" would have done that..... :huh:

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7 minutes ago, Christopher Low said:

I was almost successful on my second attempt. I say almost because.....although I successfully captured the glideslope, pressing "Z" to disengage the autopilot on final approach did not seem to work.

Did you assign a custom function in the FMC's "Autopilot" section for A/P disconnect?   From memory, the default assignment is not 'Z' (so as not to clash with default FSX/P3D assignments).  So you'll need to set a custom function.  

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The default assignment is "Z" for the PMDG 737 NGX, and it works perfectly fine with that aircraft. Are you saying that it is different for the 747?

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17 minutes ago, Christopher Low said:

The default assignment is "Z" for the PMDG 737 NGX, and it works perfectly fine with that aircraft. Are you saying that it is different for the 747?

It might well be - just check the 747's FMC key assignments page and you'll find out. I have no issues disconnecting the AP, but I use a completely different custom assignment for the QOTS  ('X' key).    The PMDG birds do not use any aspects of the default AP, so worth checking as it certainly won't 'read' any default AP assignments from the sim.

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If you use FSUIPC I believe it is AP MASTER. That's what I use and bind it to one of the yoke buttons. Double push. Autothrottle has one too, but can't remember that name off hand.

As far as throttle level position, I have "in hold mode only" set and I make it a habit of matching my throttle lever position throughout the descent and approach (to some extent). Even in cruise I do it occasionally to occupy time.There are times in descent, when in hold mode, that I find myself burning off too much speed. I can then bump the levers off of idle and bring my speed back up.

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On 12/4/2017 at 1:34 PM, Christopher Low said:

I have just attempted my first autopilot controlled flight in the 747-400, and I noted some differences to the 737 NGX (which is to be expected). The 737 NGX seems to automatically enter ALT HOLD mode when reaching cruise altitude.

This is also not the correct way. if the 737 engages in ALT HOLD when reaching cruise altitude set in FMC, this means that your climb was performed outside vnav. the 737 should also read VNAV PATH when reaching cruise altitude. Make sure you have engaged vnav on the MCP panel.

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That's an interesting comment, Alfredo. I always activate VNAV and LNAV before I initiate pushback in the 737, but for some reason the VNAV light always goes OFF soon after I depart....

My third attempt at an FMC controlled 747-400 flight was a success (EGBB Birmingham to EIDW Dublin). I just disconnected the AP by clicking the DISENGAGE button on the MCP. Much more realistic than pressing the "Z" key :smile:

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51 minutes ago, Christopher Low said:

I just disconnected the AP by clicking the DISENGAGE button on the MCP. Much more realistic than pressing the "Z" key

Actually, if you are referring to the disengage bar below the A/P buttons - not at all. This is not the correct way to disengage the autopilot: it is an emergency system. 

The normal way to disengage the A/P is via the disengage switch on the control wheel, which should be mapped to the FS "A/P master" control.

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1 hour ago, Christopher Low said:

That's an interesting comment, Alfredo. I always activate VNAV and LNAV before I initiate pushback in the 737, but for some reason the VNAV light always goes OFF soon after I depart....

My third attempt at an FMC controlled 747-400 flight was a success (EGBB Birmingham to EIDW Dublin). I just disconnected the AP by clicking the DISENGAGE button on the MCP. Much more realistic than pressing the "Z" key :smile:

The normal procedure to disengage the autopilot in both aircraft is by pressing the disengage button ON the control column. you can map that button trough the FMC options. in the 747 you RIGHT CLICK the screw just above the FD switch.

If your vnav disappears then something on your lateral revision is causing a reversion. check your FMC legs page to ensure everything is ok. on climb the FMA should read VNAV SPD

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Stable on final approach during my second flight, disconnected the AP, adjusted the power slightly to correct the glideslope.....and a massive surge of power resulted in one of my worst ever landings in the 747. In short, I had forgotten to reduce the throttles from the full power setting when taking off :blush: I really need to start writing things down....

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