2 hours ago, jcomm said:

Patricio,

look at the last post at the Aerowinx thread I started early today to ask about the altitude set for the last segment before FAF ... It can be airline specific and you can read there:

"However, I believe this is something which is airline-specific.

I'm familiar with setting MDA (rounded down) in this circumstance, but recently I was chatting with a friend who flies for a major US airline and it turns out their procedure for a VNAV approach is to set threshold elevation.

So horses for courses, as they say..."

So, you were actually not wrong in doing as you did 🙂 and I am always learning...

I understand. Going to check Aeroxinx thread to learn more. I can fly PMDG in all my sim Collection without problems with Altitude setting to do Approach and landings.

My question is about XP11 Boeing Flightfactor 777 Worldliner Professional not descending according to FMC LEGS page info.

Again here the video. https://drive.google.com/file/d/1dNM2vQfdI1TJpSpWTN4cLCwgzUT61IuT/view?usp=sharing

Happy Holidays to all.

Patricio

5 hours ago, trisho0 said:

l not descending according to FMC LEGS page info.

This is still a VNAV ALT thing (not related to what you set the MCP to), looking at FF they do the alt knob thing - so probably PMDG simulates it wrong if its not the same.

-if the plane has already reached the MCP level, it won´t ascend/descend unless you set the new MCP level + pressing the knob to execute

I know this from

While building

 

Edited January 1, 20215 yr by mSparks

11 hours ago, trisho0 said:

I understand. Going to check Aeroxinx thread to learn more. I can fly PMDG in all my sim Collection without problems with Altitude setting to do Approach and landings.

My question is about XP11 Boeing Flightfactor 777 Worldliner Professional not descending according to FMC LEGS page info.

Again here the video. https://drive.google.com/file/d/1dNM2vQfdI1TJpSpWTN4cLCwgzUT61IuT/view?usp=sharing

Happy Holidays to all.

Patricio

Trisho 🙂 what my daughter called her friend Patrício when she was 4 🙂 - btw: Trisha is what I call a colleague of mine mamed Patrícia ehehehe...

I will ask further in that thread about the approach mode logic in the 777. Some of the pilots there are actually 777 drivers as well... but I believe there's no difference there, and I will look again at your video, but mSparks gave the right answer above when he said that you were supposed to use ALT intervention ( press the ALT MCP button to start the descent ) because you were in VNAV ALT mode at the cruise segment altitude (*), @ 8000 ft, when you set the ALT to rw27L threshold + 50 ft, meaning you reached the first descent leg at cruise FL. Under such circumstance ( watch the two videos above, at the saved play times, the first by Jon an actual 777 captain that uses PSX and the second by "Britjet" a retired 744 BA pilot / instructor ) the only way to transition between VNAV ALT, entered the moment you dialled the lower altitude ino the MCP ALT window, into VNAV PTH is by pressing the ALT knob.

Happy Holidays to you too Trisho !

(*) Well, this could only happen when you do not set the next altitude before reaching TD. It actually appears to me you set it right above TD. I don't remember if there's a limiting distance from the ToD point you should set the ALT to a new value ( lower ) in order to automatically start the descent, but I will try to find out.

One test you could run would be to set it, say, at least 20 NM before reaching TD, and see if in that way your 777 automatically initiates the descent.

Watch this segment of the VNAV Des video by Britjet where he talks about setting the new altitude before reaching ToD. Actually, watch the whole video if you can :-)

Edited January 1, 20215 yr by jcomm

Further on this subject and from tw new posts at that other thread ( Aerowinx Forum )

"For the 747-400 specifically, whether the MCP altitude is set to the MDA or TDZE is irrelevant when using VNAV. The MCP just needs to be set far enough below the FAF altitude to be out of the way. For the Legacy FMC, inside the FAF the FMC is assured to be in the "on approach" mode, meaning the MCP altitude can be set above the airplane altitude without causing VNAV ALT to display. When inside the FAF and more than 300' below the MAA, set the MCP to the MAA.
The NGFMC transitions to the approach mode when flaps are out of up. As such, the MCP can be set to MAA before the FAF for VNAV Non-ILS approaches. The Boeing procedure changed recently for the NGFMC to the following:
With flaps out of up and 300 below MMA, set the MCP to the MAA.
As all our 747-400s are NGFMC, we transitioned to this procedure last year."

and this other one,

"

(...)

At our airline, we set the MCP to MDA by adding 50 feet and then rounding to the next highest 100 feet (670 feet becomes 800 feet).

Under FAA rules (which govern our operation), no part of the aircraft must descend below MDA unless certain visual and positional requirements are met. By setting MDA+50 feet, should we have to execute a missed approach, we ensure that as the engines spool up and the aircraft momentum transitions from downwards to upwards, the landing gear and aft fuselage/empennage will remain above MDA, not violating regulations. The “Minimum” aspect of MDA is what dictates this procedure. It’s a MINIMUM altitude.

In case of a non-precision approach with a DA, we set the MCP to DA rounded to the next 100 feet (we do not add 50 feet), since DA is a DECISION altitude AT which we are allowed to decide whether to initiate a missed approach, therefore penetrating the DA “layer” while transitioning is allowed.

The easy way to remember this is MDA=“Must Do Arithmetic”, DA=“Don’t Add”.

As you can clearly see, it’s all about each carrier and the way the respective regulating authority approved their procedures.
 

(...)
"

Edited January 4, 20215 yr by jcomm

On 1/1/2021 at 4:13 AM, jcomm said:

Trisho 🙂 what my daughter called her friend Patrício when she was 4 🙂 - btw: Trisha is what I call a colleague of mine mamed Patrícia ehehehe...

I will ask further in that thread about the approach mode logic in the 777. Some of the pilots there are actually 777 drivers as well... but I believe there's no difference there, and I will look again at your video, but mSparks gave the right answer above when he said that you were supposed to use ALT intervention ( press the ALT MCP button to start the descent ) because you were in VNAV ALT mode at the cruise segment altitude (*), @ 8000 ft, when you set the ALT to rw27L threshold + 50 ft, meaning you reached the first descent leg at cruise FL. Under such circumstance ( watch the two videos above, at the saved play times, the first by Jon an actual 777 captain that uses PSX and the second by "Britjet" a retired 744 BA pilot / instructor ) the only way to transition between VNAV ALT, entered the moment you dialled the lower altitude ino the MCP ALT window, into VNAV PTH is by pressing the ALT knob.

Happy Holidays to you too Trisho !

(*) Well, this could only happen when you do not set the next altitude before reaching TD. It actually appears to me you set it right above TD. I don't remember if there's a limiting distance from the ToD point you should set the ALT to a new value ( lower ) in order to automatically start the descent, but I will try to find out.

One test you could run would be to set it, say, at least 20 NM before reaching TD, and see if in that way your 777 automatically initiates the descent.

Watch this segment of the VNAV Des video by Britjet where he talks about setting the new altitude before reaching ToD. Actually, watch the whole video if you can :-)

Patricia = Trisha

Patricio = Trisho

=========================================

Regarding, on your good exposition for me to understand and to watch the videos I appreciate that so much. Holidays time kept me busy around and no flights done yet.

I learned TD green sign near to 10nm is the time to start descending from my cruise of 8,000 ft ALT. Next flight with XP11 I will follow your explanations.

Thanks again,

Patricio

On 1/4/2021 at 9:02 AM, jcomm said:

Further on this subject and from tw new posts at that other thread ( Aerowinx Forum )

"For the 747-400 specifically, whether the MCP altitude is set to the MDA or TDZE is irrelevant when using VNAV. The MCP just needs to be set far enough below the FAF altitude to be out of the way. For the Legacy FMC, inside the FAF the FMC is assured to be in the "on approach" mode, meaning the MCP altitude can be set above the airplane altitude without causing VNAV ALT to display. When inside the FAF and more than 300' below the MAA, set the MCP to the MAA.
The NGFMC transitions to the approach mode when flaps are out of up. As such, the MCP can be set to MAA before the FAF for VNAV Non-ILS approaches. The Boeing procedure changed recently for the NGFMC to the following:
With flaps out of up and 300 below MMA, set the MCP to the MAA.
As all our 747-400s are NGFMC, we transitioned to this procedure last year."

and this other one,

"

(...)

At our airline, we set the MCP to MDA by adding 50 feet and then rounding to the next highest 100 feet (670 feet becomes 800 feet).

Under FAA rules (which govern our operation), no part of the aircraft must descend below MDA unless certain visual and positional requirements are met. By setting MDA+50 feet, should we have to execute a missed approach, we ensure that as the engines spool up and the aircraft momentum transitions from downwards to upwards, the landing gear and aft fuselage/empennage will remain above MDA, not violating regulations. The “Minimum” aspect of MDA is what dictates this procedure. It’s a MINIMUM altitude.

In case of a non-precision approach with a DA, we set the MCP to DA rounded to the next 100 feet (we do not add 50 feet), since DA is a DECISION altitude AT which we are allowed to decide whether to initiate a missed approach, therefore penetrating the DA “layer” while transitioning is allowed.

The easy way to remember this is MDA=“Must Do Arithmetic”, DA=“Don’t Add”.

As you can clearly see, it’s all about each carrier and the way the respective regulating authority approved their procedures.
 

(...)
"

That is high level knowledge for Pilots and former Pilots I guess. I am not intended to become a real Pilot but virtual with my sims. Still even though, that is a very good material to learn.

Patricio