VDP

[John Collins]

There is nothing wrong with the chart. When the VGSI and descent angles not coincident that is how the VDP is charted. Search other charts with the same situation.

The VDA and the VGSI have precisely the same descent angle, but there is a 3+ foot difference in the TCH which causes the note to be added.

 

[luvflyin]

The VDA and the VGSI have precisely the same descent angle, but there is a 3+ foot difference in the TCH which causes the note to be added.

Hmm. In the real world of flying a VDA, as opposed to charting it, it’s rarely going to be precise. Altimeter instrument error and temperature are going to effect it. Unlike something fixed, like a Glideslope or VGSI which are unaffected by those.

 

[John Collins]

Hmm. In the real world of flying a VDA, as opposed to charting it, it’s rarely going to be precise. Altimeter instrument error and temperature are going to effect it. Unlike something fixed, like a Glideslope or VGSI which are unaffected by those.

That depends on the method used by the equipment to provide vertical guidance. A Baro-VNAV system will have the GP move in space with temperature, but in the case of a GS using an ILS, a VGSI, or +V advisory vertical provided by a WAAS GPS, they are all independent of temperature and don't move in space, so are fixed with similar accuracy and precision.

 

[luvflyin]

That depends on the method used by the equipment to provide vertical guidance. A Baro-VNAV system will have the GP move in space with temperature, but in the case of a GS using an ILS, a VGSI, or +V advisory vertical provided by a WAAS GPS, they are all independent of temperature and don't move in space, so are fixed with similar accuracy and precision.

I was talking about VDA’s where no Glideslope/Glidepath is generated to follow by needle.

 

[texasclouds]

Page tree, VDP baby!

 

[luvflyin]

@RussR . Two plates. I may have to do it in two posts. Is there something in the 8260’s where Jeppesen got the info to display the VDA track in the profile view the way they did? Or did they figure it out on their own?

 

[luvflyin]

 

[luvflyin]

Page tree, VDP baby!

We may make it to Fower

 

[RussR]

@RussR . Two plates. I may have to do it in two posts. Is there something in the 8260’s where Jeppesen got the info to display the VDA track in the profile view the way they did? Or did they figure it out on their own?

They calculate it themselves. That "4.5 nm to RW 20" distance is not documented on the 8260-3/5 form.

 

[luvflyin]

They calculate it themselves. That "4.5 nm to RW 20" distance is not documented on the 8260-3/5 form.

Thx

 

[aterpster]

View attachment 106956

They calculate it themselves. That "4.5 nm to RW 20" distance is not documented on the 8260-3/5 form.

What about what I have highlighted?

 

[luvflyin]

View attachment 106956
What about what I have highlighted?

Ok. That's the VDA angle and the TCH. That wouldn't be what we were talking about. 'Extending' the VDA beyond the fix where it starts.

 

[RussR]

View attachment 106956
What about what I have highlighted?

That's the VDA, but that wasn't the question. The question had been where does the charted "4.5 nm to RW 20" that is on the Jepp chart for BYI come from. "4.5 nm to RW 20" is not a value provided on the 8260-5, so Jeppesen must be calculating it themselves.