PMDG 777 Struggling Through Descend

[Remys 4]

Hello Guys,

 

I do have one question, I am always Struggling through the Descend Phase as if it not really managed, I always have to drag and adjust manually the descend rate ......... speed breaks most of the time extended and speed takes time to slow down. in the real thing, things don't go that way.

 

any suggestion, any solution, Am I missing something ? 

 

thanking you in advance

[aentwis 61]

Might be an issue with real world weather and the aircraft not having the information.

 

If you use the T7 with real weather (like AS2016 or something) you will need to enter the winds at altitude data into the flight management system...

 

As I understand it, the manual explains how to do this...

 

A

[Remys 4]

Might be an issue with real world weather and the aircraft not having the information.

 

If you use the T7 with real weather (like AS2016 or something) you will need to enter the winds at altitude data into the flight management system...

 

As I understand it, the manual explains how to do this...

 

A

Hello,

I am using PFPXalong with ASN and Uploading the Wind and Altitude into the FMC. Upload Wind Data Link. do not face any problem during climb just during descend. Drag all the time message from FMC and spoilers 90% retracted too .... I am really out of options during the descend phase.

 

PS: I am Flying the 777 300 [PFPX and ASN]

[scandinavian13 5,192]

Hello,

I am using PFPXalong with ASN and Uploading the Wind and Altitude into the FMC. Upload Wind Data Link. do not face any problem during climb just during descend. Drag all the time message from FMC and spoilers 90% retracted too .... I am really out of options during the descend phase.

 

PS: I am Flying the 777 300 [PFPX and ASN]

 

Where are your hardware throttles when all of this is happening?

[Remys 4]

 

 

Where are your hardware throttles when all of this is happening?

my hardware throttle mid position but the autopilot sets them to Idle, so Ihave Idle displayed. no throttle power engines at Idle thrust

[scandinavian13 5,192]

my hardware throttle mid position but the autopilot sets them to Idle, so Ihave Idle displayed. no throttle power engines at Idle thrust

 

Not entirely true.

 

The autothrottle will set them to idle, but then the mode reverts to HOLD. HOLD mode allows the throttles to be manually manipulated. In the real aircraft, the throttles are servo driven back to the idle position. Yours aren't. Manually move them to idle prior to TD and I'm willing to bet that the issue disappears.

 

If you'd prefer not to worry about it, you can change the AT hardware override setting via MENU > PMDG SETUP > SIMULATION (on the CDU).

[Remys 4]

 

 

Yours aren't. Manually move them to idle prior to TD and I'm willing to bet that the issue disappears

 

I will try a short Flight now and will move the throttles to idle position manually before initiating the Descend and will let you know with the outcome. finger crossed

[downscc 1,327]

Yeah, this is a common problem because idle N1 is not the same at FL320/0.80M as on the ground.  The sure indication is your fuel flow which should be about 3.2 lbs x 1000 / hr.

 

I always use the override in hold/arm option and show position when moving, and make sure the throttle controller is on the idle stop.  A quick nudge of the throttles while in hold you can see the moving blue arc to confirm aircraft throttles are idle.

 

Another consideration is your descent airspeed.  I usually change the default ECON value such as 314 KIAS to a STAR speed constraint such as 280, and the speed may increase to 290+ but I let it go until approach the published constraint.  Usually, the V/S has decreased before then and she is slowing on her own and only a few miles of speedbrakes are required.  This is part of energy management, which is something that is a major factor in flying a big heavy.

[Remys 4]

Might be an issue with real world weather and the aircraft not having the information.

 

If you use the T7 with real weather (like AS2016 or something) you will need to enter the winds at altitude data into the flight management system...

Yours aren't. Manually move them to idle prior to TD and I'm willing to bet that the issue disappears

 

I would like to Thank you for you great Help and Support. Actually I did three test flights and they worked as a charm:

problems that I was facing and solution as given has been adapted:

1- my first error is that I was just uploading the CLB Wind Data and not uploading the Winds for the Descend, so I upload it to the FMC

   

2- Setting Throttle to Idle Prior to TD

these two things saved my life didnt even had to Drag.

 

On Another Hand I do have some clarification on 4 issues listed below:

 

1- I am not having correct readings for the TAT for instance it is displaying +26 C on a level of 280 attached is the screenshot whereas it should at least be -27 C

2- Getting Insufficient Fuel from FMC although I have the right profiles in PFPX unless there's an updated profile for PMDG 777 300 [using PFPX 1.28]

3- Flight Plan from PFPX new version not loading Correctly [ I am manually adjusting the Plan]

4- Unable to fligh cruise altitude although it should be able [but i believe that this error is from the FP exported from PFPX] I believe that I have to adjust all of the airways and stuff manually in order to have a proper plan

[Remys 4]

I am also facing now a new problem. after landing Autoland, the autopilot won't disconnect in any way. whatever I do it remains active ........... very weird issue never experienced it

[downscc 1,327]

Please don't double post the same topic.

 

Regarding TAT, -26C might be the SAT but TAT is usually around -10 to -5C at the FL300 region.  Higher temperature is always a weather engine problem, what are you using?

 

I've not had problems with PFPX fuel predictions but again this can be weather related. Is it using the same winds aloft as the flight?  And I see the remaining are PFPX related. They have an active forum over at Aerosoft and the manual is very complete.  Most of us here don't mind answering one or two questions about other products but your questions reveal you need more than that.

[Remys 4]

You are completely right. PFPx and other issues not related to PMDG 777 are not to be written or posted here.

 

but regarding the Temperature, for instance In otherplanes, lets Say FsLAb A320 it givess like : TAT: -27, SAT: -24 , ISA +1 at FL of 280 same value as ASN. I was just wondering how to read the real external Temp on the PMDG 777 . 

[downscc 1,327]

. I was just wondering how to read the real external Temp on the PMDG 777 .

 

The SAT is available in the FMC.., check PROG page 2.

 

Are you familiar with TAT?  It's not a tattoo in this context, just Google "total air temperature."  Airspeed has everything to do with the measurement.

[pcubine 143]

uploading the CLB Wind Data

There is no CLB Wind Data that I am aware of. Where did you get this from? It's either cruise or descent forecasted winds.

 

Unable to fligh cruise altitude although it should be able

An updated profile will make no difference. PFPX has a tendency to pick altitudes that are very close to the top of optimum altitude. Go with what the FMC says and not what PFPX says. Sometimes I have seen it planning steps climbs that are above the maximum altitude.

[Remys 4]

On 9/26/2016 at 3:14 PM, scandinavian13 said:

If you'd prefer not to worry about it, you can change the AT hardware override setting via MENU > PMDG SETUP > SIMULATION (on the CDU

in the PMDG Menu I should Set the A/T Manual Override to:

1- Always

2- In Hold Mode Only

3- Never

 

Which Option Should I Choose. [and Should I Also Set Trim Manually to Idle] Honestly I prefer to let the plane manage the Throttles during descend phase to avoid the problem