Class C airspace
E49616
Class C airspace is a category of controlled airspace around busy airports that requires two-way radio communication and air traffic control clearance for participating aircraft.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Class C airspace canonical | 8 |
How this entity was disambiguated
This entity first appeared as the object of triple T383839 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Class C airspace Context triple: [United States airspace, includes, Class C airspace]
-
A.
Class B airspace
Class B airspace is a highly controlled airspace surrounding the nation’s busiest airports, designed to manage dense traffic with strict entry and communication requirements for pilots.
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B.
Class A airspace
Class A airspace is the highest controlled airspace layer in the United States, typically used for high-altitude en route flight under instrument flight rules (IFR) by commercial and other high-performance aircraft.
-
C.
National Airspace System
The National Airspace System is the integrated network of U.S. airspace, air traffic control facilities, navigation aids, airports, and regulations that enables the safe and efficient operation of civil and military aviation.
-
D.
Air Traffic Control Centre
The Air Traffic Control Centre is a Belgian Air Force unit responsible for managing and coordinating military air traffic within Belgian airspace.
-
E.
Air Route Traffic Control Centers
Air Route Traffic Control Centers are FAA-operated facilities that provide en route air traffic control services for aircraft flying through high-altitude sectors of U.S. airspace between departure and arrival terminal areas.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Class C airspace Target entity description: Class C airspace is a category of controlled airspace around busy airports that requires two-way radio communication and air traffic control clearance for participating aircraft.
-
A.
Class B airspace
Class B airspace is a highly controlled airspace surrounding the nation’s busiest airports, designed to manage dense traffic with strict entry and communication requirements for pilots.
-
B.
Class A airspace
Class A airspace is the highest controlled airspace layer in the United States, typically used for high-altitude en route flight under instrument flight rules (IFR) by commercial and other high-performance aircraft.
-
C.
National Airspace System
The National Airspace System is the integrated network of U.S. airspace, air traffic control facilities, navigation aids, airports, and regulations that enables the safe and efficient operation of civil and military aviation.
-
D.
Air Traffic Control Centre
The Air Traffic Control Centre is a Belgian Air Force unit responsible for managing and coordinating military air traffic within Belgian airspace.
-
E.
Air Route Traffic Control Centers
Air Route Traffic Control Centers are FAA-operated facilities that provide en route air traffic control services for aircraft flying through high-altitude sectors of U.S. airspace between departure and arrival terminal areas.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
airspace classification
ⓘ
controlled airspace ⓘ |
| appliesTo |
IFR aircraft
ⓘ
VFR aircraft ⓘ |
| associatedWith |
primary airport with operational control tower
ⓘ
radar approach control facility ⓘ |
| chartDepiction | solid magenta line ⓘ |
| definedBy | Federal Aviation Administration ⓘ |
| doesNotRequire | explicit ATC clearance phraseology for VFR entry once two-way communication is established ⓘ |
| exampleAirportType | airports with scheduled passenger service and significant operations ⓘ |
| governedBy | 14 CFR Part 71 ⓘ |
| hasLateralStructure |
core surface area radius of 5 nautical miles
ⓘ
shelf area radius of 10 nautical miles ⓘ |
| hasPrimaryPurpose |
enhance safety and efficiency of airport operations
ⓘ
separate IFR traffic from VFR traffic near busy airports ⓘ |
| hasVerticalStructure |
core surface area from surface to 4,000 feet above airport elevation
ⓘ
shelf area typically from 1,200 feet to 4,000 feet above airport elevation ⓘ |
| hasWeatherMinimums |
3 statute miles flight visibility
ⓘ
cloud clearance 500 feet below, 1,000 feet above, 2,000 feet horizontal ⓘ |
| implementedIn | many medium-sized U.S. airports ⓘ |
| isLessRestrictiveThan | Class B airspace ⓘ |
| isMoreRestrictiveThan | Class D airspace ⓘ |
| mayInclude | outer area for radar services ⓘ |
| outerAreaRadius | typically 20 nautical miles ⓘ |
| provides |
conflict resolution advisories
ⓘ
radar services to IFR and VFR aircraft ⓘ safety alerts ⓘ sequencing to the primary airport ⓘ traffic advisories ⓘ |
| requires |
Mode C transponder
ⓘ
air traffic control clearance for entry ⓘ establishment of two-way communication with ATC ⓘ operable two-way radio ⓘ two-way radio communication ⓘ |
| requiresAircraftEquipment |
altitude-reporting transponder
ⓘ
two-way radio capable of communicating with ATC ⓘ |
| requiresEntryCondition | two-way communication established when ATC states aircraft call sign ⓘ |
| requiresPilotAction |
comply with ATC instructions
ⓘ
contact approach control before entering ⓘ maintain listening watch on assigned frequency ⓘ |
| requiresTransponder |
within 10 nautical miles of primary airport at or above 10,000 feet MSL if within Mode C veil of nearby Class B
ⓘ
within and above Class C airspace ⓘ |
| surrounds |
airports with moderate traffic levels
ⓘ
airports with radar approach control ⓘ busy airports ⓘ |
| symbolizedOn | VFR sectional charts ⓘ |
| trafficLevel | moderate traffic density ⓘ |
| usedIn |
National Airspace System
ⓘ
surface form:
United States National Airspace System
|
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Class C airspace Description of subject: Class C airspace is a category of controlled airspace around busy airports that requires two-way radio communication and air traffic control clearance for participating aircraft.
Referenced by (8)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
National Airspace System