On 18/04/2014 12:25, Nightjar wrote:
On 18/04/2014 12:13, JimK wrote:
What's the definition of "built up" area?

There is none in the Air Navigation Order or the Rules of the Air, which
refer to a congested area. However, I assumed most people would
understand what a built up area is.

I should, perhaps, add that it is not particularly relevant in any case.
It only affects the low flying rule and that does not apply to aircraft
landing or taking off in accordance with normal aviation practice.

Colin Bignell