Class A airspace
E48727
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.
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
airspace class
→
controlled airspace → |
| abbreviation |
Class A
→
|
| altimeterSettingReference |
standard pressure setting 29.92 inHg
→
|
| altitudeReference |
flight levels
→
|
| appliesOver |
adjacent international waters within 12 NM of U.S. coast
→
contiguous United States → most of Alaska → |
| appliesTo |
all aircraft operating within its vertical and lateral limits
→
|
| ATCServiceRequired |
true
→
|
| chartDepiction |
described in IFR en route charts and regulations
→
not specifically depicted as Class A on VFR sectional charts → |
| classificationSystem |
U.S. National Airspace System
→
|
| clearanceRequired |
IFR clearance required
→
|
| communicationRequirement |
two-way radio communication with ATC
→
|
| controlledBy |
Air Route Traffic Control Centers
→
|
| country |
United States
→
|
| entryRequirement |
IFR flight plan
→
|
| flightLevelRange |
FL180 to FL600
→
|
| governingBody |
Federal Aviation Administration
→
|
| IFRRequired |
true
→
|
| includes |
airspace overlying Alaska within specified limits
→
airspace overlying coastal waters within 12 nautical miles of the U.S. coast → airspace overlying the contiguous United States → |
| introducedBy |
Federal Aviation Administration
→
|
| lowerLimit |
18,000 feet MSL
→
|
| navigationRequirement |
IFR-approved navigation equipment
→
|
| primaryRulesOfFlight |
Instrument Flight Rules
→
|
| purpose |
provide positive control of high-altitude traffic
→
support efficient routing of high-performance aircraft → |
| regulatoryReference |
14 CFR Part 71
→
14 CFR Part 91 → |
| relatedConcept |
Class B airspace
→
Class C airspace → Class D airspace → Class E airspace → Class G airspace → |
| safetyFunction |
separation of IFR aircraft
→
|
| surveillance |
radar-based ATC separation
→
|
| SVFRPermitted |
false
→
|
| transponderRequirement |
Mode C or better transponder required
→
|
| typicalUsers |
air carrier aircraft
→
business jets → high-performance aircraft → |
| upperLimit |
60,000 feet MSL
→
|
| usage |
en route high-altitude flight
→
|
| verticalExtent |
from 18,000 feet MSL up to and including FL600
→
|
| VFRPermitted |
false
→
|
| weatherMinimums |
IFR weather minimums apply
→
|
Referenced by (2)
| Subject (surface form when different) | Predicate |
|---|---|
|
United States airspace
→
|
includes |
|
Class B airspace
→
|
isLessRestrictiveThan |