JimL, Hullaballoo, Mark Six,
As you have proved, the whole issue is fraught with minor details, in essence the operational legislation provides for the method of operating the aircraft, and the certification legislation gives you the aircraft criteria which you need to fulfill in order to be able to operate to these minima. The F and the N already possess the Flight Manual Supplement, 11.2 for the F and Supplement 2 for the N, which give all required operational data to fly to PC1 through CAT A equivalence. The other various Eurocopter documents tell you what you have to do in order to comply with the Airframe requirements. On the performance side of things, it just means that you have to reduce your take-off weight in order to maintain the necessary OEI performance to be able to land safely or fly away, rather than have an organized crash!!
In order to accommodate existing aircraft, particularly in countries in EASA-land which may not have such a developed rotary infrastructure, ie which still operate a high proportion of the old twins, aka BO105, A 109, or AS355 F or N, the EASA operational team have fine tuned the Cat A certification requirements through the "Acceptable Means of Compliance" documentation which in effect through "grand-fathering" rights allow certain older types to operate, through CAT A equivalence.
The problem arises now because nobody is willing to step forward and give the EASA certification officer (Mark Winstanley) a copy of the DGAC approval letter which confirms that the AS355 has Cat A equivalence, ie does conform to legislation which was brought out after it was originally certified.
Thank you Mark Six for the kind offer of a copy of your DGAC letter, I would be very grateful if you could send me a good quality scan of this by mail; I will pm you now. If anybody else out there has
any other relevant documents issued by the DGAC , however old, I would be grateful if you could let me know.
I will repost back here when this is sorted out, which will hopefully be soon!!
Biz-Buz