Airspace - Class C

Class Charlie Airspace

• Inner core: Surface to 4000' AGL, 5 NM radius
• Shelf area: 1,200' AGL (no lower) to 4,000' AGL, 10 NM radius

Class A   - MSL 18,000 - FL60
Class B   - Tower
Class C   - Tower   Inner Core  Surface to 4000' AGL 5NM Radius  

                              Outer Core  1,200'AGL (no lower) to 4,000 AGL 10NM Radius 

Class D   - Tower  2500' AGL  5 Miles Radus
Class E   - Anywhere
Class G  - Non-Towered

Class Airspace

• Airspace Dimension                          4 N.M /2,500' AGL
• Communication Requirements          Two Way Contact
• Equipment Requirements                  Two way Radio
• Pilot Requirements                            Student 
• Weather Requirements                      500' below clouds/1,000' above Clouds/2,000' away clouds

Introduction:

• Class C Airspace areas are designed to improve aviation safety by reducing the risk of midair collisions in the terminal area and enhance the management of air traffic operations therein around airports that have a certain number of IFR operations or passenger enplanement
• Surround those airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations or passenger enplanements
• Unless otherwise authorized by ATC, each aircraft operation in Class C airspace must be conducted in compliance with FAR 91.129 and 91.130
• For the purpose of this section, the primary airport is the airport for which the Class C airspace area is designated
• A satellite airport is any other airport within the Class C airspace area
• Class C airspace supports both Instrument Flight Rules (IFR) and Visual Flight Rules (VFR) operations within

Airspace Dimensions:

• Horizontal Limits:
• Class C airspace areas should initially be designed as two circles centered on the airport reference point
• Inner core: Surface to 4000' AGL, 5 NM radius
• Shelf area: 1,200' AGL (no lower) to 4,000' AGL, 10 NM radius
• Wherever possible, use VOR radials and DME arcs to define the boundaries of the airspace and any of its sub-areas
• It is important, however, that prominent visual landmarks also be considered to assist the VFR traffic preferring to remain clear of this area
• Vertical Limits:
• The ceiling of a Class C airspace should be 4,000 feet MSL above the primary airport’s field elevation
• The airspace within the 5 NM circle must extend down to the surface
• The airspace between the 5 and the 10 NM circle(s) must extend no lower than 1,200 feet AGL
• Altitude dimensions will be charted in MSL
• Though not requiring regulatory action, an Outer Area is the procedural companion to Class C airspace
• The normal radius of an Outer Area is 20 NM from the primary Class C airspace airport
• Its vertical limit extends from the lower limits of radio/radar coverage up to the ceiling of the approach control’s delegated airspace, excluding the Class C airspace itself, and other airspace as appropriate

Airspace Depiction:

• Charted on Sectionals, IFR En Route Low Altitude, and Terminal Area Charts where appropriate

ATC Facility:

• Terminal Radar Approach Control (TRACON)
• Also known as approach control
• Air Traffic Control Tower (ATCT)
• Also known as "tower"

Operations:

• Class C airspace area locations must include a single primary airport around which the Class C airspace is designated
• These areas may be designated full-time or part-time. If part-time, the effective time must be stated in local time

Figure 3: Monterey (KMRY) Class Charlie Airspace

VFR Visibility Requirements:

• 3 SM visibility, 500' below, 1,000' above, 2,000' horizontal

Entry Requirements:

• Two-way radio communication must be established with the ATC facility providing ATC services prior to entry and thereafter maintain those communications while in Class C airspace
• Pilots of arriving aircraft should contact the Class C airspace ATC facility on the publicized frequency and give their position, altitude, radar beacon code, destination, and request Class C service
• Radio contact should be initiated far enough from the Class C airspace boundary to preclude entering Class C airspace before two-way radio communications are established
• Permission is recognized by hearing your call sign
• ATC clearance for IFR, all require radio contact
• Pilot: "[Agency], [Position], [Altitude], [Transponder Code], [Destination], [Request]"
• ATC: "Aircraft calling, standby"
• ATC: "[Callsign] report [Instructions]"
• Unless otherwise authorized by ATC, a transponder in compliance with 91.215
• After January 1, 2020, the applicable Automatic Dependent Surveillance-Broadcast Out equipment specified in 91.225

NOTE:
1. If the controller responds to a radio call with, “(aircraft callsign) standby,” radio communications have been established and the pilot can enter the Class C airspace

2. If workload or traffic conditions prevent immediate provision of Class C services, the controller will inform the pilot to remain outside the Class C airspace until conditions permit the services to be provided

3. It is important to understand that if the controller responds to the initial radio call without using the aircraft identification, radio communications have not been established and the pilot may not enter the Class C airspace

4. Though not requiring regulatory action, Class C airspace areas have a procedural Outer Area. Normally this area is 20 NM from the primary Class C airspace airport. Its vertical limit extends from the lower limits of radio/radar coverage up to the ceiling of the approach control’s delegated airspace, excluding the Class C airspace itself, and other airspace as appropriate. (This outer area is not charted)

5. Pilots approaching an airport with Class C service should be aware that if they descend below the base altitude of the 5 to 10 mile shelf during an instrument or visual approach, they may encounter non-transponder, VFR aircraft

Departures from:

• A primary or satellite airport with an operating control tower:
  • Two-way radio communications must be established and maintained with the control tower, and thereafter as instructed by ATC while operating in Class C airspace
• A satellite airport without an operating control tower:
  • Two-way radio communications must be established as soon as practicable after departing with the ATC facility having jurisdiction over the Class C airspace

Qualifications:

• Student pilot certificate

Aircraft Separation:

• Separation is provided within the Class C airspace and the outer area after two-way radio communications and radar contact are established
• IFR, SVFR, and runway operations
• IFR will be separated from VFR
• VFR aircraft are separated from IFR aircraft within the Class C airspace by any of the following:
1. Visual separation
2. 500' vertical; except when operating beneath a heavy jet
3. Target resolution
• Wake turbulence separation will be provided to all aircraft operating:
  • Behind and less than 1,000 feet below super or heavy aircraft,
  • To small aircraft operating behind and less than 500 feet below B757 aircraft, and
  • To small aircraft following a large aircraft on final approach

NOTE:
1. Separation and sequencing of VFR aircraft will be suspended in the event of a radar outage as this service is dependent on radar. The pilot will be advised that the service is not available and issued wind, runway information and the time or place to contact the tower

2. Separation of VFR aircraft will be suspended during CENRAP operations. Traffic advisories and sequencing to the primary airport will be provided on a workload permitting basis. The pilot will be advised when CENRAP is in use

3. Pilot participation is voluntary within the outer area and can be discontinued, within the outer area, at the pilot's request. Class C services will be provided in the outer area unless the pilot requests termination of the service

4. Some facilities provide Class C services only during published hours. At other times, terminal IFR radar service will be provided. It is important to note that the communications and transponder requirements are dependent of the class of airspace established outside of the published hours

Secondary Airports:

• In some locations Class C airspace may overlie the Class D surface area of a secondary airport
  • In order to allow that control tower to provide service to aircraft, portions of the overlapping Class C airspace may be procedurally excluded when the secondary airport tower is in operation
  • Aircraft operating in these procedurally excluded areas will only be provided airport traffic control services when in communication with the secondary airport tower
• Aircraft proceeding inbound to a satellite airport will be terminated at a sufficient distance to allow time to change to the appropriate tower or advisory frequency. Class C services to these aircraft will be discontinued when the aircraft is instructed to contact the tower or change to advisory frequency
• Aircraft departing secondary controlled airports will not receive Class C services until they have been radar identified and two-way communications have been established with the Class C airspace facility
• This program is not to be interpreted as relieving pilots of their responsibilities to see and avoid other traffic operating in basic VFR weather conditions, to adjust their operations and flight path as necessary to preclude serious wake encounters, to maintain appropriate terrain and obstruction clearance or to remain in weather conditions equal to or better than the minimums required by 14 CFR Section 91.155. Approach control should be advised and a revised clearance or instruction obtained when compliance with an assigned route, heading and/or altitude is likely to compromise pilot responsibility with respect to terrain and obstruction clearance, vortex exposure, and weather minimums

Air Traffic Services

• When two-way radio communications and radar contact are established, all participating VFR aircraft are:
  1. Sequenced to the primary airport
  2. Provided Class C services within the Class C airspace and the outer area
  3. Provided basic radar services beyond the outer area on a workload permitting basis. This can be terminated by the controller if workload dictates

Restrictions:

• 200 knots (230 mph) within 4 NM and 2,500' of the primary airport of a Class C airspace area, unless otherwise authorized

Figure 4: Class Charlie Legend Inset

Notes:

• When above Class Charlie airspace, a transponder is required
• When below Class Charlie airspace, a transponder is not required
• Class Charlie airspace is not always operated full time
• When operating out of an airport within class Charlie airspace, you should contact ATC as soon as practicable
• There is an outer area which extends 20 NM out for the purpose of establishing communication
• Services provided include:
• Sequencing
• Services outside of the airspace dimensions
• Basic radar services workload permitting
• Table 3-2-1 of the AIM provides a list of Class C airspace by states
• Traffic patterns. No person may take off or land an aircraft at a satellite airport within a Class C airspace area except in compliance with FAA arrival and departure traffic patterns
• Communications. Each person operating an aircraft in Class C airspace must meet the following two-way radio communications requirements:
• Arrival or through flight. Each person must establish two-way radio communications with the ATC facility (including foreign ATC in the case of foreign airspace designated in the United States) providing air traffic services prior to entering that airspace and thereafter maintain those communications while within that airspace
• Departing flight. Each person:
• From the primary airport or satellite airport with an operating control tower must establish and maintain two-way radio communications with the control tower, and thereafter as instructed by ATC while operating in the Class C airspace area; or
• From a satellite airport without an operating control tower, must establish and maintain two-way radio communications with the ATC facility having jurisdiction over the Class C airspace area as soon as practicable after departing
• An operator may deviate from any provision of this section under the provisions of an ATC authorization issued by the ATC facility having jurisdiction over the airspace concerned
• ATC may authorize a deviation on a continuing basis or for an individual flight, as appropriate

Conclusion:

• Standardization is key and so variations in airspace design are only applied when absolutely required based on local requirements