Entering NAT TRACK Points in RTA Progress Page

[Kevin Handl 1]

Hey, Today i got a restriction from Oceanic to not cross a Certain Waypoint on the Track at a Time, i was not able to put in for example 6120N into the RTA Progress page

 

Anybody knows something about this?

 

Thank you

[thibodba57 462]

1 hour ago, Kevin Handl said:

Hey, Today i got a restriction from Oceanic to not cross a Certain Waypoint on the Track at a Time, i was not able to put in for example 6120N into the RTA Progress page

 

Anybody knows something about this?

 

Thank you

Haven't played with this function of the 777.  But did you try other formats of the fix like N61W020?

[Kevin Handl 1]

Yes, i tried as you said, even the Whole lenght i already tried, always saying invalid entry

[downscc 1,327]

Copy the waypoint from the LEGS page to the scratchpad, then copy from the scratchpad to the RTA page... little trick I use just don't know if it's something kosher or unique to PMDG.

[Kevin Handl 1]

i tried that Sir, invalid Entry it says 😞

[downscc 1,327]

Seems odd that the RTA waypoint field would not take 6120N.  These shortcut names are the same as any other waypoint in the world in that they are contained in the navdata file wpNavFIX.txt and that's how 6120N is converted to N61 W020.  Is it possible that the time restriction is outside the range that the RTA can operate?

[Kevin Handl 1]

i need to clarify, if you fly a Oceanic you put the MACH Number into the Legs page, after exiting the track back to ECON.

Maybe thats the Reason why the RTA is locked?

[thibodba57 462]

20 minutes ago, Kevin Handl said:

i need to clarify, if you fly a Oceanic you put the MACH Number into the Legs page, after exiting the track back to ECON.

Maybe thats the Reason why the RTA is locked?

Possibly. I'd have to look in the NG FMS guide to see if one takes precedence over the other.  Did you change the entry point to .XXM and after or did you just modify the VNAV speed?

[downscc 1,327]

Yeah... you cannot have a fixed speed segment and an RTA. Back to the original clearance where the restriction was crossing a waypoint not before or after a specified time, on closer evaluation I would say this removes any speed constraint and you do not set a fixed Mach rather the RTA is set up to comply with clearance.  I'd certainly confirm that with controller first.

[CaptainLars 21]

A) a constant speed segment does not work together with RTA, and B) once you had a constant speed segment, the RTA function is broken on this flight. It's a bug it seems.

[downscc 1,327]

2 hours ago, CaptainLars said:

A) a constant speed segment does not work together with RTA, and B) once you had a constant speed segment, the RTA function is broken on this flight. It's a bug it seems.

I almost agree with your conclusion, but not having tried it I have to ask what if the RTA were not used until after the aircraft exited the constant speed segment.  Once that segment is behind, it is no longer a consideration right?  At this point forward the RTA should work within its normal limits..... or is this where you say it is broke?

[scandinavian13 5,192]

I'm confused. RTA and constant speed are in direct opposition to each other.

Constant speed means "maintain this speed."

RTA means "modulate speed to hit this point at this time."

 

Trying to ask for both is a bit like telling someone to drive somewhere a mile away at 60mph, but then telling them that they need to take 5 minutes to get there.

That won't work, and if the FMS is telling you that won't work, then I'd hardly consider that a bug.

[Budbud 227]

I guess the idea here is to set an RTA up to say 6120N then a constant speed segment after that waypoint.

As we all know, the NAT are normally flown at constant Mach number hence the constant speed segment from the entry point to the exit point. But the ATC may also give a "cross not before XXXXZ".

I know I use constant speed segment often when crossing the Pond but I seldom use the RTA function and I don't recall having attempted to use both at the same time.

In any case, if both function cannot be programmed at once on different segments, then you have to set the constant speed segment once you have passed the waypoint for which you set the RTA.

Edited September 12, 2018 by Budbud

[CaptainLars 21]

19 hours ago, downscc said:

I almost agree with your conclusion, but not having tried it I have to ask what if the RTA were not used until after the aircraft exited the constant speed segment.  Once that segment is behind, it is no longer a consideration right?  At this point forward the RTA should work within its normal limits..... or is this where you say it is broke?

Excactly this is the point where it's broke. Once you have your constant speed segment completed, you cannot use RTA correctly, which could be useful, of course, when you have a longer flight where the constant speed segment is only one part of the flight. There's a series of cifers appearing instead on Progress page 3, where the RTA normally can be inserted.

[downscc 1,327]

I found another post I touched recently  regarding RTA and I now remember reading in the FCOM that the constant speed segment can be terminated either by entering an ECON or LRC or using RTA.  So according to the book the PMDG 777 doesn't behave the same way.  Please document this on a trouble ticket so it can be added to the bug tracking system.  If it's not there it might not ever get fixed.