traffic advisories shall be issued when this procedure is applied. 

Note: This procedure shall not be provided utilizing mosaic radar systems. 

CONFORMANCE- The condition established when an aircraft's actual position is within the conformance region constructed around that aircraft at its position, according to the trajectory associated with the aircraft's Current Plan. 

CONFORMANCE REGION- A volume, bounded laterally, vertically, and longitudinally, within which an aircraft must be at a given time in order to be in conformance with the Current Plan Trajectory for that aircraft. At a given time, the conformance region is determined by the simultaneous application of the lateral, vertical, and longitudinal conformance bounds for the aircraft at the position defined by time and aircraft's trajectory. 

CONSOLAN- A low frequency, long-distance NAVAID used principally for transoceanic naviga- tions. 

## CONTACT- 

a. Establish communication with (followed by the name of the facility and, if appropriate, the frequency to be used). 

b. A flight condition wherein the pilot ascertains the attitude of his/her aircraft and navigates by visual reference to the surface. 

(See CONTACT APPROACH.) (See RADAR CONTACT.) 

CONTACT APPROACH- An approach wherein an aircraft on an IFR flight plan, having an air traffic control authorization, operating clear of clouds with at least 1 mile flight visibility and a reasonable expectation of continuing to the destination airport in those conditions, may deviate from the instrument approach procedure and proceed to the destination airport by visual reference to the surface. This approach will only be authorized when requested by the pilot and the reported ground visibility at the destination airport is at least 1 statute mile. 

(Refer to AIM.) 

CONTAMINATED RUNWAY- A runway is considered contaminated whenever standing water, ice, snow, slush, frost in any form, heavy rubber, or other substances are present. A runway is contami- nated with respect to rubber deposits or other 

friction-degrading substances when the average friction value for any 500-foot segment of the runway within the ALD fails below the recommended minimum friction level and the average friction value in the adjacent 500-foot segments falls below the maintenance planning friction level. 

CONTERMINOUS U.S.- The 48 adjoining States and the District of Columbia. 

CONTINENTAL UNITED STATES- The 49 States located on the continent of North America and the District of Columbia . 

CONTINGENCY HAZARD AREA (CHA)- Used by ATC. Areas of airspace that are defined and distributed in advance of a launch or reentry operation and are activated in response to a failure. 

(See AIRCRAFT HAZARD AREA.) (See REFINED HAZARD AREA.) (See TRANSITIONAL HAZARD AREA.) 

CONTINUE - When used as a control instruction should be followed by another word or words clarifying what is expected of the pilot. Example: “continue taxi,” “continue descent,” “continue inbound,” etc. 

CONTROL AREA [ICAO]- A controlled airspace extending upwards from a specified limit above the earth. 

CONTROL SECTOR- An airspace area of defined horizontal and vertical dimensions for which a controller or group of controllers has air traffic control responsibility, normally within an air route traffic control center or an approach control facility. Sectors are established based on predominant traffic flows, altitude strata, and controller workload. Pilot communications during operations within a sector are normally maintained on discrete frequencies assigned to the sector. 

(See DISCRETE FREQUENCY.) 

CONTROL SLASH- A radar beacon slash repre- senting the actual position of the associated aircraft. Normally, the control slash is the one closest to the interrogating radar beacon site. When ARTCC radar is operating in narrowband (digitized) mode, the control slash is converted to a target symbol. 

CONTROLLED AIRSPACE- An airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification. 

