Understanding Air Law

[alancorrie]

According to the BHPA Handbook, category D (controlled) airspace requires entry and transit to be granted by ATC. I've just bought an airspace map and note that all the category D zones also include reference heights. I think I already know the answer to this but can someone confirm whether ATC clearance is required at all heights, or only those within the specified range.

By way of example, where I live, the map describes the airspace as EDINBURGH CTA [D] 2,500 - 6000.

[Guest]

In the example you quote you would need to be in contact with the relevant ATC unit for flight within the Edinburgh control area between 2500' amsl (using Edinburgh's QNH) and 6000' amsl (these are altitudes, not heights). Check the map thoroughly though as there may be another stack of airspace from 6000' up stacked on top. There will also be a CTZ (control zone) that will extend from the surface up to meet that 2500' base around Edinburgh airport. Outside of this is the Class G airspace (referred to as the open FIR) where you are free to fly non-radio if you wish.

I haven't got a map that far north of Watford so the above is based on standard assumptions.

[Guest]

If you want to visualise the airspace and the different class of airspace around the area you mention, try downloading http://www.paraglide.uk.com/cloudscape/iowFlight/FlyTo-IoW.kmz this google earth file and opening it in google earth. It will answer your question visually. As v32nb says these blocks of airspace are stacked on top of each other like odd shaped building bricks. Class D blocks enable craft to get up and away from airports and often there are class A corridors above with no gap between.

the airmap shows the altitude (above mean sea level) or sometimes the flight level of the bottom and top of areas of class D space and also the bottom and top of class A space (these are mostli expressed in flight levels).

[alancorrie]

The 3d google earth map looks very good - thanks.