Exam: anywhere suitable, and make the numbers work.
Well that's my view too.
But Backpacker's 1st post in this thread is indeed near the mark as regards what prompted the question
The "nice chap" (who I shall not have the pleasure of flying with again, ever) insisted that Lydd or Southend are not acceptable alternates and that Southampton is the correct one.
I don't have problem with picking alternates for all my "real" flights. With a ~1300nm zero-fuel range I normally pick a selection of airports which have the approach aids (ILS being the one of choice by far), avgas, Customs, and which one would not mind being stuck in for a day or two. In most places in Europe (north of say Italy or Greece) this is a non-challenge. I use a satellite phone to check the tafs and metars at all the airports in question, way before I get there.
PPR/PNR is not a huge issue (IMHO) because while yes you should get PPR/PNR the reality is that once you are on your way to the alternate the situation is a full emergency and you will just declare a mayday (if necessary, in southern Europe, citing "low oil pressure") and land there regardless of any landing clearance. The only time I would obey a refusal to land (which itself would be hugely unprofessional of ATC) would be if I had other good options or if I was going to be fired at.
Obviously it would be stupid to file Gatwick or Heathrow as alternates (because there are other options nearby such as Southend which is H24 with an ILS... except the ILS is INOP right now
and doesn't cost £500 plus an absolute arm and a leg in parking costs) but in the more common context one might be talking of an airfield which is PNR/Customs but is otherwise open to GA and not busy.
I just wondered why the hell somebody would pick Southampton as the alternate in the scenario originally described. I was hoping somebody could illuminate that choice. To me it makes sense only if Bournemouth was closed due to a crash or some runway contamination etc, or the ILS became INOP and it was ~OVC004 and you wanted to be able to get home using a single train journey. Lydd and Southend are in the sticks but in nearly all cases of a wx diversion one can fly home the next morning in good VFR conditions
