Aeronautics and Space. Part135:Operating requirements: Commuter and on demand operations and rules governing persons on board such aircraft. Section135.160:Radio altimeters for rotorcraft operations.
(a) After April 24, 2017, no person mayoperate a rotorcraft unless that rotorcraft is equipped with an operableFAA-approved radio altimeter, or anFAA-approved device that incorporatesa radio altimeter, unless otherwise authorized in the certificate holder’s approved minimum equipment list.