iFly GPS Forum

it's on the EFB feature add list.

JO-oh-hn!  Will ya ple-e-e-eze just...

No, wait. I don't see any harm in discussing and clarifying the characteristics of what we each (or all) mean by "glide ring" and "glide ratio" so that AP understands what their subscribers wish for (and will settle for).

GLIDE RATIO seems easy enough: I think everyone who has posted about it here has in mind that iFly include a way of displaying the airplane's current vertical speed as a numerical ratio, such as -9:1. That is, 9 feet horizontal for every 1 foot down. An additional Instrument would do that just fine, I think, and would be a very easy addition to the list of available Instruments. (I'd bet it's a one-day project or less. Maybe one hour.)

GLIDE RING would be a graphic projection overlaid on the Map and could be based on:

--the Glide Ratio and Glide Speed data entered by the user in Current Aircraft Profile (Menu>Setup>Edit Aircraft...)

--the GPS groundspeed

--terrain data

--winds aloft data

--etc.

So it's more complicated than a simple Glide Ratio instrument and would almost certainly take more time and resources to code.

For an existing glide ring already in wide use, here's a screenshot of Garmin Pilot's "Glide Range Ring" on my iPhone yesterday:

As you see, the "Glide Range Ring" depicts the estimated area I could glide to if the engine quit. It's a bit wider to the north because there was about a 10 knot crosswind from the south.  So it's considering (at least) altitude and wind in addition to data I had entered about my airplane. And it's dead simple to understand in an emergency. For example, I had just flown over Barney McGlaughlin's seaplane base and probably would have tried to get back to it deadstick. But one glance at the glide range ring would show that I didn't have a chance of getting there with no engine--not even if the bridge and power line weren't in the way.

It's one of only two things I still like about Garmin Pilot--but I almost never use the app in flight, so this function is useless to me in an emergency. If iFly had something similar, I'd be more comfortable while flying.

Thanks, John!  I'd either never noticed that feature of NRST, or else had completely forgotten it. So it's two pokes to get that info, one for NRST and the other for the exclamation point. That identifies airports you can make, given the glide ratio you've previously entered for your aircraft.

But what if NO airports are within range?

Alas, that feature isn't likely to help me, except for the rare times I'm flying high enough and there's a charted airport within range.

I want to see at a glance ALL of the territory within gliding range--without having to poke anything. That's needed to make a quick decision on which direction to point the nose when NO airports are within range.

I usually fly an amphibian, so I want the range to include water. See my note about the seaplane base depicted in my screenshot, earlier. I couldn't have made it to my friend's familiar SPB; but I could easily get to plenty of safe places ahead--such as a sheltered area with a beach that I know of near the forward edge of the glide range ring. But could I make it? The ring said yes.

Or in ANY airplane crossing big water it would be comforting to see at a glance that the green ring extends ahead to the far shore. There may not be an airport in range, but it's healthier to ditch a hundred feet of shore than out in open water. (Even seaplanes make lousy rowboats.)

Absolute accuracy isn't isn't absolutely necessary in most engine-out situations--in none of them that I've experienced. And a reasonable estimate is a lot better than nothing at all.