Well, the problem only arrises when you are flying procedural approaches (e.g. N. Sweden or Norway) when there is no radar coverage. In those cases, I have sometimes had to inform ATC "Cleared the VOR?DME approach 23, be advised we will commence the procedure from non-standard 3300 ft. today due to temperature". Has never been a problem - although sometimes, the ATCO would need an explaination as to why this was so (good way to spend the 12 NM outbound leg!
)
Brgds
Empty