- C -

Calibrated Airspeed: Indicated airspeed corrected for instrumentation errors, but not for air density.

Calibration: A basic control to a data source from controls and displays for calibrating a device. Calibration is also a procedure used to adjust physical devices so that they provide the most accurate results possible. Calibration procedures commonly result in correction factors to be downloaded from the host processor of the device; during calibration, the device is usually not available.

Cant Angle: Angle of nacelle mounting.

Capture Criterion: A test case used to determine if an armed objective has been captured. In avionics, an aircraft might have an objective to fly to a radial of a radio station, then to fly along it. While en route, the objective is armed, meaning that the crew and software are attempting to reach the radial. The radial is captured and the objective is met when the capture criteria is met. An objective can have multiple criteria. Capture criterion are often used with radio navigation to determine a transition from armed to active.

Capture: To attain an objective, such as reaching a radial of a radio station.

CAS: Calibrated airspeed.

Casualty: A loss of property due to fire, storm shipwreck or other casualty, which is allowable as a deduction in computing taxable income.

Category as defined by the FAA:
(1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a broad classification of aircraft. Examples include: airplane; rotorcraft; glider; and lighter-than-air; and 
(2) As used with respect to the certification of aircraft, means a grouping of aircraft based upon intended use or operating limitations. Examples include: transport, normal, utility, acrobatic, limited, restricted, and provisional. 
"Category A," with respect to transport category rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure. 
"Category B," with respect to transport category rotorcraft, means single-engine or multiengine rotorcraft which do not fully meet all Category A standards. Category B rotorcraft have no guaranteed stay-up ability in the event of engine failure and unscheduled landing is assumed. 
"Category II operations", with respect to the operation of aircraft, means a straight-in ILS approach to the runway of an airport under a Category II ILS instrument approach procedure issued by the Administrator or other appropriate authority. 
"Category III operations," with respect to the operation of aircraft, means an ILS approach to, and landing on, the runway of an airport using a Category III ILS instrument approach procedure issued by the Administrator or other appropriate authority. 
Category IIIa operations, an ILS approach and landing with no decision height (DH), or a DH below 100 feet (30 meters), and controlling runway visual range not less than 700 feet (200 meters). 
Category IIIb operations, an ILS approach and landing with no DH, or with a DH below 50 feet (15 meters), and controlling runway visual range less than 700 feet (200 meters), but not less than 150 feet (50 meters). 
Category IIIc operations, an ILS approach and landing with no DH and no runway visual range limitation.”

Cause of Action: The plaintiff’s legal claim against the defendant. There is often more than one cause of action in a lawsuit.

Caution: A signal which alerts the operator to an impending dangerous condition requiring attention, but not necessarily immediate action; more critical than an advisory but less critical than a warning.

CCLIM: Course cut limit.

Ceiling: The height above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as broken, overcast, or obscuration.

CEP: Circular error probability.

Certified Travel Counselor: One who has passed a series of rigorous tests of professional competency administered by the Institute of Certified Travel Agents.

Channel: A number that maps to a frequency.

Circular Error Probability (CEP): A probability that a percentage of two-dimension measurements will lie within a circle of given radius, with the circle centered at truth or mean of the measurements.

Civil Law: That part of the law which governs relationships between people where there is no criminal activity involved.

Clarke 1866 and Clarke 1880: Standard models for computing earth data.

Class: (1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a classification of aircraft within a category having similar operating characteristics. Examples include: single engine; multiengine; land; water; gyroplane; helicopter; airship; and free balloon; and (2) As used with respect to the certification of aircraft, means a broad grouping of aircraft having similar characteristics of propulsion, flight, or landing. Examples include: airplane; rotorcraft; glider; balloon; landplane; and seaplane.

Co-Defendant: A defendant joined together with one or more other defendants in the same case.

Collective Cue: A vertical flight director cue for rotary-wing aircraft, primarily to control altitude, by changing power.

Collective: A flight control operated by moving up or down with hand in rotary-wing aircraft, primarily to control lift (altitude); controls the collective or total pitch of the rotors on a rotary-wing aircraft.

Commanded: Controls given to a device.

Commercial Airline: An airline that carriers passengers.

Commercial Operator: A person who, for compensation or hire, engages in the carriage by aircraft in air commerce of persons or property, other than as an air carrier or foreign air carrier or under the authority of Part 375 of this title. Where it is doubtful that an operation is for "compensation or hire", the test applied is whether the carriage by air is merely incidental to the person's other business or is, in itself, a major enterprise for profit.

Common Law: Body of law that has grown based on the decisions of courts long ago. It originated in England and has since passed to the United States. It is always changing to reflect the current needs society.

Communications: How well equipment is communicating.

Commuter: An air carrier operator operating under 14 CFR 135 (Code of Federal Regulations) that carries passengers on at least five round trips per week on at least one route between two or more points according to its published flight schedules that specify the times, day of the week, and places between which these flights are performed. The aircraft that a commuter operates has 30 or fewer passenger seats and a payload capability of 7,500 or less.

Comparative Negligence: A defense to negligence used when it is believed that the plaintiff’s negligence contributed to his or her injuries. Based on the amount of negligence by each party, the amount of damages is adjusted accordingly.

Complaint: A pretrial document filed in a court by one party against another that states a grievance, called a “cause of action.”

Complementary Filter: A filter in which the complement of the filter is desired, giving the effect of a high-pass filter by implementing a low-pass filter; a filter for combining multiple data sources, usually of different types, by adding filtered values, where the sum of the filters in the frequency domain is unity; a Kalman filter with fixed gains. Complementary filters are often designed in the frequency domain in way that that the filters determined at build time such that the cutoff frequency of the LFP is equal to that of the HPF. This provides the advantages of DNS's long-term accuracy and INS's short-term accuracy, while filtering DNS's high-frequency noise and INS's slow drift.

Computer Cycle: In a periodic, cyclical computer system, the most basic, fastest timing loop.

Contingency Fee Agreement: An agreement between an attorney and their client, which allows the attorney to be paid only if the client prevails in a lawsuit and collects monetary damages. The lawyer then receives a percentage of the damages, generally 1/3 of the award.

Continuous Time: Time which can have any point expressed as a real quantity without regard for any specific interval or processing rate.

Continuous-Time Equation: A mathematical relationship to describe a function of time; expressed in terms of continuous time.

Contributory Negligence: A defense to negligence, which points out that the plaintiff’s negligence contributed to his or her injuries. Contributory negligence is an absolute bar to the plaintiff’s recovery against the defendant.

Control Law: The mathematical definition of a system used to control or to change the dynamic response of a system.

Control Surface: An airfoil attached to an aircraft that is moved to control the attitude of the aircraft; an surface to control flight of an aircraft indirectly, such as a swashplate to control pitch of rotor blades.

Controlled Altitude (CTALT): A guidance control law parameter, generated by the vertical guidance modes; altitude that is being controlled.

Controlled speed (CTS): A guidance control law parameter, generated by the longitudinal guidance modes; speed that is being controlled.

Coriolis Acceleration: Tangential acceleration caused by motion on a radial on a rotating surface. In aviation, it is acceleration in the earth's longitudinal direction caused by changing latitude, usually computed from system state data.

Corrected Altitude: Measured pressure altitude corrected for instrumentation errors.

Counterclaim: A demand by the defendant against the plaintiff asserting an independent cause of action in the same lawsuit.

Coupled: Describes operation of flight director in which automatic flight control system causes flight controls to follow commands from flight director or errors from guidance.

Course Cut Limit (CCLIM): A guidance control law parameter, generated by the lateral guidance modes; limits the intercept angle of the flight path with a desired course, typically 45degrees.

Course: Towards a point specified initially.

Creeping Line Search: A pattern of equally spaced parallel lines followed for searching the ground from an aircraft.

Critical Altitude: The maximum altitude at which, in standard atmosphere, it is possible to maintain, at a specified rotational speed, a specified power or a specified manifold pressure. Unless otherwise stated, the critical altitude is the maximum altitude at which it is possible to maintain, at the maximum continuous rotational speed, one of the following: 
(1) The maximum continuous power, in the case of engines for which this power rating is the same at sea level and at the rated altitude. 
(2) The maximum continuous rated manifold pressure, in the case of engines, the maximum continuous power of which is governed by a constant manifold pressure.

Cross Examination: Questioning the witness who has been presented by the opposition at trail or a deposition.

Cross Track: Perpendicular to the course.

Cross-track Deviation Gain: A guidance control law parameter, generated by the lateral guidance modes; relative weighting of cross-track deviation in the lateral control law.

Cross-track Deviation: A guidance control law parameter, generated by the lateral guidance modes; distance from the aircraft to a desired course measured along a perpendicular to the course.

CTS: Controlled speed.

Cue: An indicator to an operator for control placement, tells the operator where to place controls; synonyms with command.

Cutoff Frequency: The frequency at which the gain of a filter is at an edge of a band, usually taken to be when gain is 0.5, or -3.01dB; the frequency at which the output of a filter is half the power of the input.