The credit card mobile phones now provided on some aircraft, do not interfere with aircraft systems because they are wired to a special "base station" that has been designed to safely receive and transmit radio signals in the aircraft.
Captains can use credit card mobile phones for free
( z1 possible :ARG1 ( z2 use :ARG0 ( z3 person :ARG0-of ( z4 have-org-role :ARG2 ( z5 captain ) ) ) :ARG1 ( z6 phone :ARG1-of ( z7 mobile ) :mod ( z8 card :mod ( z9 credit ) ) ) :ARG1-of ( z10 free ) ) )