(a) A certificated repairman may perform or supervise the maintenance,
preventive maintenance, or alteration of aircraft or aircraft components
appropriate to the job for which the repairman was employed and
certificated, but only in connection with duties for the certificate
holder by whom the repairman was employed and recommended.
(b) A certificated repairman may not perform or supervise duties under
the repairman certificate unless the repairman understands the current
instructions of the certificate holder by whom the repairman is employed
and the manufacturer's instructions for continued airworthiness relating
to the specific operations concerned.