Pilot/Controller Glossary Pilot/Controller Glossary  8/15/19 7/16/20  violate a succeeding altitude restriction or altitude  assignment.  (See ALTITUDE RESTRICTION.)  (Refer to AIM.)  CROSS (FIX) AT OR BELOW (ALTITUDE)- Used by ATC when a maximum crossing altitude at  a specific fix is required. It does not prohibit the  aircraft from crossing the fix at a lower altitude;  however, it must be at or above the minimum IFR  altitude.  (See ALTITUDE RESTRICTION.)  (See MINIMUM IFR ALTITUDES.)  (Refer to 14 CFR Part 91.)  CROSSWIND- a.  When used concerning the traffic pattern, the  word means “crosswind leg.”  (See TRAFFIC PATTERN.)  b.  When used concerning wind conditions, the  word means a wind not parallel to the runway or the  path of an aircraft.  (See CROSSWIND COMPONENT.)  CROSSWIND COMPONENT- The wind compo- nent measured in knots at 90 degrees to the  longitudinal axis of the runway.  CRUISE- Used in an ATC clearance to authorize a  pilot to conduct flight at any altitude from the  minimum IFR altitude up to and including the  altitude specified in the clearance. The pilot may  level off at any intermediate altitude within this block  of airspace. Climb/descent within the block is to be  made at the discretion of the pilot. However, once the  pilot starts descent and verbally reports leaving an  altitude in the block, he/she may not return to that  altitude without additional ATC clearance. Further, it  is approval for the pilot to proceed to and make an  approach at destination airport and can be used in  conjunction with:  a.  An airport clearance limit at locations with a  standard/special instrument approach procedure. The  CFRs require that if an instrument letdown to an  airport is necessary, the pilot shall make the letdown  in accordance with a standard/special instrument  approach procedure for that airport, or  b.  An airport clearance limit at locations that are  within/below/outside controlled airspace and with- out a standard/special instrument approach  procedure. Such a clearance is NOT AUTHORIZA- TION for the pilot to descend under IFR conditions  below the applicable minimum IFR altitude nor does  it imply that ATC is exercising control over aircraft  in Class G airspace; however, it provides a means for  the aircraft to proceed to destination airport, descend,  and land in accordance with applicable CFRs  governing VFR flight operations. Also, this provides  search and rescue protection until such time as the  IFR flight plan is closed.  (See INSTRUMENT APPROACH  PROCEDURE.)  CRUISE CLIMB- A climb technique employed by  aircraft, usually at a constant power setting, resulting  in an increase of altitude as the aircraft weight  decreases.  CRUISING ALTITUDE- An altitude or flight level  maintained during en route level flight. This is a  constant altitude and should not be confused with a  cruise clearance.  (See ALTITUDE.)  (See ICAO term CRUISING LEVEL.)  CRUISING LEVEL- (See CRUISING ALTITUDE.)  CRUISING LEVEL [ICAO]- A level maintained  during a significant portion of a flight.  CT MESSAGE- An EDCT time generated by the  ATCSCC to regulate traffic at arrival airports.  Normally, a CT message is automatically transferred  from the traffic management system computer to the  NAS en route computer and appears as an EDCT. In  the event of a communication failure between the  traffic management system computer and the NAS,  the CT message can be manually entered by the TMC  at the en route facility.  CTA- CTAF- CTAS- CTOP- CTRD- (See CONTROLLED TIME OF ARRIVAL.)  (See ICAO term CONTROL AREA.)  (See COMMON TRAFFIC ADVISORY  FREQUENCY.)  (See CENTER TRACON AUTOMATION  SYSTEM. )  (See COLLABORATIVE TRAJECTORY  OPTIONS PROGRAM)  (See CERTIFIED TOWER RADAR DISPLAY.)  PCG C-9 