The rules that use the category "<altitude_directive>" are:

<basic_air_command>

<altitude_directive>

<controller_flight_advisory-not_recursive-adj-proceed_as_briefed>

<controller_flight_advisory-recursive-proceed_as_briefed> <altitude_directive>

<controller_flight_advisory>

<controller_flight_advisory-recursive-proceed_as_briefed> <altitude_directive>

<controller_flight_advisory-proceed_as_briefed>

<controller_flight_advisory-recursive-proceed_as_briefed> <altitude_directive>

<basic_air_command-recursive>

<altitude_directive>

<airspace_clearance>

<airspace_clearance-recursive> <altitude_directive>

<controller_flight_advisory-not_recursive-adj>

<controller_flight_advisory-recursive-proceed_as_briefed> <altitude_directive>