iFly GPS Forum

So, when I was up flying with iFly GPS app on my Android table for the first time today, I was right next to an airport (maybe a mile?) at approx. 2000' AGL, and I thought I'd try out the NRST button (and more specifically, the red-exclamation-point button) to see what it would say. And though my high-drag plane has only a 6.6 to 1 glide ratio, I could've made that airport easily. Yet all the direction/distance boxes for all the airports (including the one I was next to) were red, which I assume means the software is telling me that those airports are not within my glide. Has anyone else verified that the software is working correctly? Is it subtracting some big fudge factor to allow for loss of altitude due to maneuvering? Was I just not as close as I thought (seriously, I think I would've had to burn off a lot of altitude to get down onto the strip). Thanks.

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Powrachute PC 2000; Aventura II; Cherokee 180

OK, here's my limited testing results (it was a low-ceiling, gusty day, and I'm a real light plane).

I got up to 2500' AGL and stayed near my airport (KAWO). I then re-approached the airport (three times) and determined that the background color of the airport directional arrow (in NRST/Emergency mode) stayed red until 1.3 miles from the airport (at which point it went to yellow), and at 1.2 miles would turn to green.

Visually, at 1.3 miles it appeared that I was practically on top of the edge of the airport. It was definitely overkill to have that be the "green" distance. (Granted, the airport is large'ish, with 3 runways, one of which is 5300' long; and I assume your distance estimate is based on the center of the airport, so even at the edge I'm a 1/2 mile from the center).

Just to test it out I flew away from the airport, turned around, and at 2.5 miles, heading more or less into about an 8-10 mph wind, I cut the engine to idle (which in my pusher plane is a bit of a "brake" vs a "push" at that RPM), trimmed for best glide, and coasted it down to across the airport boundary. I would've hit the center of the runway I was lined up on.

So, yes, there may be a little too much fudge factor in your calculations. Personally, I always figure I could lose at least 500' of altitude due to maneuvering and/or not holding perfectly on the best-glide speed. So, maybe figure a loss of 1000' to be safe. In this instance, that would mean I had 1500' (out of 2500') of altitude to use up on my "emergency" glide. At my 6.6:1 glide ratio (which iFly GPS was using): 6.6 x 1500 = 9900' of ground can get covered, which divided by 5280 (feet per mile) = 1.875 miles. So, I think that even with a generous fudge factor, 1.8 miles should be the "green zone" (or at least yellow), not 1.2.

Thanks.

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Powrachute PC 2000; Aventura II; Cherokee 180

Heck! I didn't even know this indication whether my aircraft can make it to a "nearest" airport was evewn available for my IFLY on Android devices.

Then again, I'm consulting the latest manual Rev 092512 published in 2012. This is the latest I could find.

Are these features highlighted in a later manual? Is there a later manual?

John