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GRID MORA


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giannisd
giannisd
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On your maps, sometime, the Grid MORA does not respect the rule of the safest altitude: 1.000 ft above the ground/sea or 2.000 ft when the highest point is over 3.000 ft in the considered area.
On the attached picture you will see a Mora 9.9 whereas the highest mountain is 9.544 ft, and 8.5 where the highest mountain is 8.123 ft
Generally, on central Italy, your Grid Mora is only ab. 300/400 ft above the highest obstacle, but are correct in the Alps region.
‌Could you explain me how is calculated your Grid Mora and the rule you are considered ?
regards,
Gianni‌‌

giannisd
giannisd
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giannisd - 2/1/2017 2:23:00 PM
On your maps, sometime, the Grid MORA does not respect the rule of the safest altitude: 1.000 ft above the ground/sea or 2.000 ft when the highest point is over 5.000 ft in the considered area.
On the attached picture you will see a Mora 9.9 whereas the highest mountain is 9.544 ft, and 8.5 where the highest mountain is 8.123 ft
Generally, on central Italy, your Grid Mora is only ab. 300/400 ft above the highest obstacle, but are correct in the Alps region.
‌Could you explain me how is calculated your Grid Mora and the rule you are considered ?
regards,
Gianni‌‌



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Edited 2/1/2017 2:25:08 PM by giannisd
Tim Dawson
Tim Dawson
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You are using the term MORA, I am unsure where you got that from. SkyDemon can show maximum grid elevations, which is the highest hard stuff (terrain or obstacle attached to terrain) that we know of in that grid square. It's then up to the pilot to add whatever safety margin they wish to that figure, if they want to do something with it.
giannisd
giannisd
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Tim Dawson - 2/2/2017 10:31:18 AM
You are using the term MORA, I am unsure where you got that from. SkyDemon can show maximum grid elevations, which is the highest hard stuff (terrain or obstacle attached to terrain) that we know of in that grid square. It's then up to the pilot to add whatever safety margin they wish to that figure, if they want to do something with it.

MORA Minimum Off Route Altitude,  or depending from chart publisher, sometime AMA Area Minimum Altitude‌, have the same use.
‌There are two types of Minimum Off Route Altitudes (MORAs) – one is called a route MORA and the other is the grid MORA.
MORA's give at least 1,000 feet altitude clearance above terrain, and 2,000 feet in mountainous (an area of changing terrain were the changes of terrain elevation exceed 3000 feet within a distance of 10NM) terrain.
Route MORAs provided an obstacle clearance within 10 nautical miles (19 km) on both sides of the airways and within a 10-nautical-mile (19 km) radius around the ends of the airways.
Grid MORAs provide an obstacle clearance altitude within a latitude and longitude grid block, usually of one degree by one degree. They are presented in feet (ft), omitting the last two figures. Example: 7,600 feet is given as 76.
Grid MORA values clear all terrain and obstructions by 1000 feet in areas where the highest elevations are 5000 feet MSL or lower. MORA values clear all terrain by 2000 feet in areas where the highest elevations are 5001 feet MSL or higher.

‌Route MORA are typical IFR use or on Airway, Grid MORA are used in VFR on area G.

Better indicate clearly, on SkyDemon User Manual, that your AMA or MORA (name is not important) do not consider buffer and indicate the maximum obstacle altitude on the grid‌‌.
The majority of Pilots learned that Grid MORA (AMA) indicated on charts, are calculated with the buffer as per above.
‌‌All ICAO standard charts follow the rule.
Hoping to be helpful to the improvement of SD,
my ‌best regards,
Gianni‌‌‌
‌    ‌

Tim Dawson
Tim Dawson
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Thank you. We are happy with our Maximum Elevation Figures and customers appears to be happy with them too. I took a quick look at a couple of paper charts I found in the office (Germany and UK) and the figures shown there do not appear to be derived as you described above.

Whe‌‌n it comes to your route SkyDemon will calculate a minimum safe altitude for each leg and this can be found in the PLOG. It's based on parameters that you control in the planning options.
giannisd
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Tim Dawson - 2/2/2017 2:43:11 PM
Thank you. We are happy with our Maximum Elevation Figures and customers appears to be happy with them too. I took a quick look at a couple of paper charts I found in the office (Germany and UK) and the figures shown there do not appear to be derived as you described above.

Whe‌‌n it comes to your route SkyDemon will calculate a minimum safe altitude for each leg and this can be found in the PLOG. It's based on parameters that you control in the planning options.
OK I must accept your Maximum Elevation,  but I have Jeppesen and ICAO maps and they apply a safest altitude on MEF.

‌See FAA:    https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/aero_guide/‌ 
https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/aero_guide/media/Chart_Users_Guide_12thEd.pdf‌
and:    http://desktop.arcgis.com/en/arcmap/10.3/tools/production-mapping-toolbox/calculate-mef-onc.htm

‌I do not remember the related to maps ICAO DOC number now,  but they also specify to rise up the MEF for safety,
regards,
Gianni‌‌ 


Edited 2/2/2017 6:03:24 PM by giannisd
Tim Dawson
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The first two of your links do not work.

The last link describes how MEF are calculated, and I can tell you that SkyDemon uses a very similar algorithm. Ours should be approximately the same as any arrived at by that method.
GO

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