ELGD Says "The B1 licence is a mechanical based licence and
permits the holder to issue certificates of release to
service following line maintenance, including aircraft
structure, power plants and mechanical and electrical
systems.
Replacement of avionic line replaceable units
requiring simple tests without the use of test equipment
to prove their serviceability is also included within the
privileges of this licence. You would know if you hold a licence, if you do and didn't, tut tut!