Under current legislation the CAA issues an Aircraft Maintenence Licence if the requirements of EC regulation 2042/2003 annex III Part-66 have been met. The criterion is that sufficent theoretical and practical experience have been acheived over a period of x years; this includes exams, essays and log book experience. Up until the 28/09/06 a CAA Section L licence under the BCAR system could be converted to a part-66 licence.
Within the BCAR system different catagories entitled the holder to issue CRSs of which he held on his/her licence; for example a mechanical licence would consist of A-airframes and C-engines, an avionic licence would include X-Electrical, X-Autopilot, Instruments, radio/radar etc.
The current EASA system brings all these seperate certifying catagories under one licence e.g A&C = B1, Avionics = B2, The official title is Line Maintenance mechanical/avionic Technician.
The A-licence is a new catagory for Line maintenance Mechanics, this was just a company authorisation in the old system. It entitles the holder a Limited authorisation of 21 ramp items that he/she may certify.
The licence in any catagory is a basic licence and thus a prerequesite. Further type training must be endorsed on the licence, the level the training is pitched at depends on the catagory held e.g B1/B2 full maintainence course level 3 (approx 12 weeks), A-licence ramp course level 1-2(approx 3 weeks).
Hope that clarifies the muddy minefield that is european legislation!!
