SkyDemon Forums

Decent to an airfield – maintain the minimum altitudes at the inbound waypoints

http://forums.skydemon.aero/Topic29468.aspx

By Tim Dawson - 9/30/2019 10:13:34 AM

You can create an extra waypoint close to the airfield and make the leg from that waypoint to the airfield at a particular altitude. SkyDemon will then implement a descent at the end of the leg before, to try to ensure you end up at that altitude before that waypoint.

SkyDemon only currently allows for one descent performance profile in your aircraft so you may need to either change that, or use an alternative aircraft profile where a rapid descent is required, if you want the performance planning to be exact.
By FyingCello - 9/27/2019 8:35:05 PM

I have a question about flight planning with SkyDemon. I plan a flight in Switzerland from Lausanne LSGL to Birrfeld LSZF, let’s say at an altitude of 5500ft. At Birrfeld I want to fly via inbound sector west to the airfield. The inbound sector west has a minimum altitude of 4000ft AMSL, the downwind at LSZF an altitude of 2000ft. I set a waypoint in sector West and pull the first Leg of from Lausanne to the waypoint. After the waypoint sector west I pull a second leg to the airfield LSZF. At leg from waypoint Sector west to the airfield I set 4000ft and choose the option "start changing level before this leg starts"

Now I've found out that SkyDemon always assumes that the last leg ends on the ground, means the last point of a route is at ground level. For this reason SD plans that the aircraft before sector West start to decent from 5500ft, based on the settings of the aircraft profile (decent rate 500ft / min). Since the last point ends at ground level, it results that at inbound sector west an altitude of only ~ 3000ft is remaining, which is too low.

How I can mitigate this planning error? Is there a way to let the last leg end in the air at a certain altitude (eg. downwind altitude 2000ft)? Or should I set a higher decent rate for the used aircraft? Is it possible to change or override the decent rate for the last leg? Or must I include the whole downwind circuit in the planning to extend the flightpath length and give the aircraft more time to decent?

Any suggestions are welcome
Marcello