Weather - Best altitude for flight

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Weather - Best altitude for flight

Author	Message
Martin Bech	Martin Bech posted 3/4/2018 7:17:19 PM Topic Details Share Topic
Group: Forum Members Posts: 152, Visits: 352	Hi When planning a flight fro Denmark to Marocco in a Cirrus SR22T with indicated speed 170kt I get data for Best altitude. If I change to a Cessna 172 with indicated speed of 100kt I get no data. What is the correlation between speed and Best altitude?
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Replies
Tim Dawson	Tim Dawson posted 3/5/2018 3:07:08 PM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.4K	Well, possibly yes. So what was actually the problem? Were you indeed flying through terrain?
	Reply Like 34
Martin Bech	Martin Bech posted 3/5/2018 6:54:30 PM Post Details Share Post
Group: Forum Members Posts: 152, Visits: 352	If I changed climb and/or decent rate - same result. If I change crusespeed to 124kt I get the result with first 4 altitudes incomplete. Changing speed to 130kt gives no incomplete. I can’t get the clue other than it has something to do with speed.
	Reply Like 36
Martin Bech	Martin Bech posted 3/8/2018 9:43:27 AM Post Details Share Post
Group: Forum Members Posts: 152, Visits: 352	+x Martin Bech - 3/5/2018 6:54:30 PM If I changed climb and/or decent rate - same result. If I change crusespeed to 124kt I get the result with first 4 altitudes incomplete. Changing speed to 130kt gives no incomplete. I can’t get the clue other than it has something to do with speed. I have now tested different situations and concludes that there must be an error i SD's weather calculations. Entering the route as on the first picture gives no problem. If I then append LECO and LEMR to the route then I get Incomplete Forecast. Try then just to create the route LEVX‌ - LECO - LEMR, then no problem. Try also to change Power Settings to 150kt for the route on picture 1 - new result. Why do the append give a problem when the LEVX, LECO, LEMR route don't? Why do a speed change change the situation? Aircraft: Service ceiling 12.000ft, Climb Rate Sea Level 560ft/min - At Service Ceiling 100ft/min - Indicated 78kt, Decent rate -900ft/min - Indicated 100kt, Power Setting Airspeed 100kt Indicated ‌‌ ‌‌
	Reply Like 32
Martin Bech	Martin Bech posted 3/8/2018 9:46:58 AM Post Details Share Post
Group: Forum Members Posts: 152, Visits: 352	+x Martin Bech - 3/8/2018 9:43:27 AM +x Martin Bech - 3/5/2018 6:54:30 PM If I changed climb and/or decent rate - same result. If I change crusespeed to 124kt I get the result with first 4 altitudes incomplete. Changing speed to 130kt gives no incomplete. I can’t get the clue other than it has something to do with speed. I have now tested different situations and concludes that there must be an error i SD's weather calculations. Entering the route as on the first picture gives no problem. If I then append LECO and LEMR to the route then I get Incomplete Forecast. Try then just to create the route LEVX‌ - LECO - LEMR, then no problem. Try also to change Power Settings to 150kt for the route on picture 1 - new result. Why do the append give a problem when the LEVX, LECO, LEMR route don't? Why do a speed change change the situation? Aircraft: Service ceiling 12.000ft, Climb Rate Sea Level 560ft/min - At Service Ceiling 100ft/min - Indicated 78kt, Decent rate -900ft/min - Indicated 100kt, Power Setting Airspeed 100kt Indicated ‌‌ ‌‌ Sorry, the text should be: Try also to change Power Settings to 150kt for the route on picture 1 with added LECO and LEMR- new result
	Reply Like 34