Airway question
If you have an airway marked on the (half mil) map which has a lower altitude marked e.g. +3000, Should this be negociated using Regional Pressure?
I appreciate that if an airfield lies within this airspace (sorry, underneath it!) then it may be sensible to use the airfield QNH but I need to know the factual position, i.e. are lower airway limits, when written in feet, based on the assumption that people wishing to pass under these airways are OK using a regional setting?