Performance A or C - what are they?

[aged]

I've noticed some companies require, in addition to a (frozen) ATPL and MCC a "Performance A" or C.
What are these?

[parkfell]

Prior to the new JAR style of exams, individual performance exams were sat depending upon the aircraft type about to be entered on your licence.

Large aircraft - perf A:exam based on L.1011
Up to 5.7 MT [Kingair/Otter/some light twins] - perf C

You had 5 years in which to consolidate a group by completing the 1179 flight test; otherwise you lost it.

The ANO lists the various groups

[aged]

Thanks for that