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I was just flying from KLGA to KBOS and was descending into Boston via the ROBUC3 arrival.

 

image.thumb.png.089b1c60a36f92140698a49e7809090b.png

 

At this point in descent, I was approaching BANKI which you can see from the chart is 16000 or above. Notice that the blue circle on the PDF shows my vertical speed to hit that should be around -400 while the DIRECT-TO screen on the FMC shows -7300. My understanding is that these should be the same -- is that incorrect? I'm not sure if there's a bug or a misunderstanding on my part.

 

qY1Foqd.jpg

 

Additionally, later on in the arrival the DIRECT-TO page on the FMC shows a constraint of 9800> for ANSLY which should be 8000 (which I confirmed on the LEGS page). The vertical speed it was giving me was correct, but I don't understand where this number came from.

 

Xm8DLLb.jpeg

 

It's not clear to me if there's something I'm not understanding or one or more bugs. I do think MERIT being stuck at the top of the DIRECT-TO screen is a bug -- I've experienced some wonkiness using that which I believe is an acknowledged area of concern in another thread. I don't remember exactly, but after take-off, it either wasn't showing up on this screen despite being my first waypoint (route KLGA MERIT ROBUCC3 KBOS) or clicking it didn't do anything so I had to type it in manually and click the top row. This messed something up in the flight plan which I easily fixed through LEGS.

 

In any case, my main question is what is the difference between the vertical speed guidance shown by the blue circle and on the DIRECT-TO screen?

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Regarding BANKI: the DIR INTC page does not do a good job of handling at-or-above or at-or-below restrictions. It just shows you the required V/S to get to the fix at the altitude associated with it (in this case, 16000). You're only a short distance away and would have 4000 feet to lose to do that, so that V/S makes sense (this is the reason that you should plan your V/S off of a hard altitude, and then just make sure it meets the requirements of whatever at-or-above or at-or-below restrictions come before that). The blue dot is more direct indication of what your V/S should be at that exact moment. So that seems correct. However, there is still an issue I'm seeing: the altitudes in the DIR INTC should come directly off of what's in the LEGS page. BANKI should be 16000, not FL214. ROBUC is a "between" restriction, so it should show FL190 until you go below FL190, at which point it should change to 12000 (and the displayed V/S should adjust accordingly). That appears to be a bug.

 

I don't have a good answer for your question about ANSLY. You're correct that it should be 8000 in the DIR INTC page, to match the restriction you see on the MFD. I have no idea why it's not. I suspect a bug there as well.

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@thecloudcitiesInteresting, thank you for the comments! The way the restrictions for ROBUC and ANSLY were being displayed definitely seem like a bug, possibly two different ones, so I hope someone on Aerosoft's support team takes a look at that. I'll try repeating the same flight tonight to see if I have different results if I avoid any issues going direct MERIT at the beginning.

 

I'm still not quite sure about the blue circle vs. the DIRECT-TO guidance though. As you can see in my first screenshot, the blue circle was telling me to decrease my rate of descent while the FMS shows me needing to increase it for every visible waypoint.

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If a waypoint has an “at or above restriction” and your flightplan (direct to page) has calculated that you are passing that waypoint above then it seems correct for me. 
 

also I believe the v/s on the direct to pages are calculated for 250kt whereas the bluedot/snowflake takes your actual speed. 



Not claiming I would know anything for sure, but that’s how I try to figure out what the aircraft is trying to tell me. 

:)

 

ps I think the direct to pages show you v/s as if you would want to decent to that hight right now and the snowflake shows more of a general path towards your destination (if that makes any sense)

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5 hours ago, Puuhbear said:

If a waypoint has an “at or above restriction” and your flightplan (direct to page) has calculated that you are passing that waypoint above then it seems correct for me. 
 

also I believe the v/s on the direct to pages are calculated for 250kt whereas the bluedot/snowflake takes your actual speed. 



Not claiming I would know anything for sure, but that’s how I try to figure out what the aircraft is trying to tell me. 

:)

 

ps I think the direct to pages show you v/s as if you would want to decent to that hight right now and the snowflake shows more of a general path towards your destination (if that makes any sense)

 

That's interesting about the differences in factoring speed, if accurate -- thanks for that.

 

The issue with the altitude constraints is that some of the values on the DIRECT-TO page seem completely random and don't align with what's entered (and correct) on LEGS.

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