Advice please Lydd EGMD to Bonn Hangelar EDKB

No problem for Germany (neither to avoid contolled airspace, nor without 8,33 and Mode S if you stay low).

For BE it will not be trivial. If really wishing to fly OCAS you would certainly have to remain below 4500’ AMSL, above that everything is controlled. Immediately below there are TMA’s and CTR’s for the main airports EBOS, EBAW, EBBR, EBLG. For example between the EBAW and EBBR CTR’s there is a narrow East-West corridor which I sometimes fly – but I know that region quite well so I have plenty of visual cues. You would best fly either North of Antwerp, but then carefully avoid Dutch airspace, or South of Brussels. On weekdays, there are some military CTR’s active to further complicate matters – EBBE is a particularly charming obstacle if going South of Brussels, and has quite a big training area associated, EBR37 if my old memory still serves.

But frankly I see no reason to remain outside CAS over Belgium. Admittedly I have no experience, as my own craft is not allowed in controlled airspace anyway, but I feel sure you could quite legally cross Belgium at FL060 or so, with your mode C xpdr and 25 kHz radio. It would certainly be more comfortable, and likely safer, too. I am sure someone with more experience “up there” will soon chime in.

BTW if you fly an Annex 2 plane, known as a “permit” plane in the UK I think, you officially need to obtain an overflight permission which costs some 90 euro’s. I quietly suggest you to accidentally overlook this detail, but recommend getting this confirmed from someone more experienced.

In Germany, you can fly even with no transponder at all, OCAS and below 5000’. No need for 8,33 kHz, either, AFAIK – the only airspace where you may need it today is Dutch.

Feel free to pm for more details.

I used to fly at FL085 or so straight across Belgium, in my long distance VFR trips, shown at the start of here

One leaves the UK just below CAS base, turns up at KONAN and asks Brussels (131.10 IIRC) for a transit X Y Z as required, FL085 or whatever. It’s called a fait accompli; a method well understood by British builders

All those old trips were done at altitude, VMC on top. Never had any problems in N Europe.

Mode S and 8.33 I have no idea. I know Dutch Mil are 8.33 now – got it a few times recently.