Possible Defect: correct calculation of MSA for legs to account for fly/over/fly by and starting and end points

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Possible Defect: correct calculation of MSA for legs to account for fly/over/fly by and starting and...

Possible Defect: correct calculation of MSA for legs to account for...

Author	Message
Tim Dawson	Tim Dawson posted 9/10/2020 1:12:08 PM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.2K	Yes, we will do that, but just for the very first leg in your journey. Edited 9/10/2020 1:12:35 PM by Tim Dawson
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lhe	lhe posted 9/10/2020 11:08:57 AM Post Details Share Post
Group: Forum Members Posts: 154, Visits: 445	+x Tim Dawson - 9/10/2020 9:49:50 AM Thank you. Yes, you have highlighted a bug in our code where certain junctions of legs could fail to correctly pick up obstructions in the arc forming the junction. The next version of SkyDemon will contain a fix to this. That great. Thank you. Could you also fix the MSA computation so that obstacles in a semicircle before the starting point of the route is considered in the MSA computations? Just as obstacles in a semicircle after the end point of the route are considered. When departing from an airport you can't always depart directly in the direction of the route. Runway in use, noise-sensitive areas and/or ATC procedures can mean that you have to fly for some time in the area "before" the route and then obstacles before the route are relevant.
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Tim Dawson	Tim Dawson posted 9/10/2020 9:49:50 AM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.2K	Thank you. Yes, you have highlighted a bug in our code where certain junctions of legs could fail to correctly pick up obstructions in the arc forming the junction. The next version of SkyDemon will contain a fix to this.
	Reply Like 4
lhe	lhe posted 9/8/2020 1:37:43 PM Post Details Share Post
Group: Forum Members Posts: 154, Visits: 445	+x lhe - 9/8/2020 11:03:36 AM Try this: Create a route from Sundbro (ESKC) airport, ESE to Skölsta (town), then NNW to STORVRETA VRP. There is an 874' antenna approximately 1.7 NM SE of Skölsta. The MSA for both route legs is given as 1600'. My settings for obstruction clearance is 10 NM horizontally, 1000 feet vertically. We've just discovered that if you reverse direction, then SkyDemon will correctly give a 1900' MSA! So there must be some bug here. Edited 9/8/2020 2:04:13 PM by lhe
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lhe	lhe posted 9/8/2020 11:03:36 AM Post Details Share Post
Group: Forum Members Posts: 154, Visits: 445	Try this: Create a route from Sundbro (ESKC) airport, ESE to Skölsta (town), then NNW to STORVRETA VRP. There is an 874' antenna approximately 1.7 NM SE of Skölsta. The MSA for both route legs is given as 1600'. My settings for obstruction clearance is 10 NM horizontally, 1000 feet vertically.
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pauls	p pauls posted 9/8/2020 9:08:22 AM Post Details Share Post
p Group: Forum Members Posts: 21, Visits: 0	+x Tim Dawson - 9/8/2020 8:53:24 AM It isn't, because that mast is more than 5nm from Binbrook and 5nm is the default setting for clearance from obstacles (for MSA purposes). If I change my preference to 6nm then the mast is taken account of. Tim i i stand correct it's 04nm outside the 5nm radius. Let me check with the other members that raised the issue and I'll come back to you
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Tim Dawson	Tim Dawson posted 9/8/2020 8:53:24 AM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.2K	It isn't, because that mast is more than 5nm from Binbrook and 5nm is the default setting for clearance from obstacles (for MSA purposes). If I change my preference to 6nm then the mast is taken account of.
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lhe	lhe posted 9/7/2020 12:10:32 PM Post Details Share Post
Group: Forum Members Posts: 154, Visits: 445	+x pauls - 9/7/2020 11:10:19 AM However I had a quick play: try Humberside -> OTR -> Binbrook (town) -> Humberside There's a mast south of Binrbook which isn't used in the MSA calc (distance 3.4nm) That's a good example.
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pauls	p pauls posted 9/7/2020 11:10:19 AM Post Details Share Post
p Group: Forum Members Posts: 21, Visits: 0	+x Tim Dawson - 9/7/2020 10:02:46 AM Can you give an example route where you observe this happening, please? SkyDemon does look for obstacles in the "circles" around turns. I'll check with the PPL/IR members that raised this - they're based on the continent near the alps! However I had a quick play: try Humberside -> OTR -> Binbrook (town) -> Humberside There's a mast south of Binrbook which isn't used in the MSA calc (distance 3.4nm)
	Reply Like 4
Tim Dawson	Tim Dawson posted 9/7/2020 10:02:46 AM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.2K	Can you give an example route where you observe this happening, please? SkyDemon does look for obstacles in the "circles" around turns.
	Reply Like 3