Christopher Low

First autopilot flight in the 747-400 QOTSII

35 posts in this topic

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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Why would we request that you do that?

No idea. I'm just the padawan here :wink:

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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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