Class Alpha Airspace

Introduction:

Class Alpha Airspace Dimensions:

  • Class Alpha Airspace Depicted
    Class Alpha Airspace Depicted
  • Vertically, Class Alpha begins at 18,000' Mean Sea Level (MSL) up to and including FL600 (about 60,000' MSL)
  • Horizontally, Class Alpha begins when within 12 Nautical Miles (NM) of the coast in 48 contiguous states and Alaska and designated international airspace beyond 12 NM off the coast of the 48 contiguous States and Alaska within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures apply
    • Examples include Santa Barbara Island, Farallon Islands, and airspace south of latitude 25°04;00" North
  • Class Alpha airspace does not include the airspace less than 1,500 feet above the surface of the earth and the Alaska Peninsula west of longitude 160°00'00" West

Class Alpha Airspace Depiction:

  • Sectional Charts
    Amazon, Sectional Charts
  • Sectional Charts
    Amazon, Sectional Charts
  • Navigation charts omit Class A airspace depictions

Class Alpha Operating Rules & Pilot/Equipment Requirements:

  • VFR Visibility Requirements:

    • Each person operating an aircraft in Class A airspace must conduct operations under Instrument Flight Rules (IFR) unless otherwise authorized
      • See 14 Code of Federal Regulations (FAR) Section 71.33, Sections 91.167 through 91.193, Sections 91.215 through 91.217, and Sections 91.225 through 91.227

  • Entry Requirements:

  • Equipment Requirements:

    • Transponder:

      • ADS-B Out Requirements
        ADS-B Out Requirements
      • Unless otherwise authorized by ATC, when operating within or above Class Bravo airspace, a 91.215 and operable ADS-B Out equipment is required
        • After January 1, 2020, the applicable Automatic Dependent Surveillance-Broadcast Out equipment specified in 91.225
      • ADS-B Out Requirements
        ADS-B Out Requirements

    • Communication Equipment:

      • Two-way radio communications with the controlling agency (described below) are required

  • Pilot Qualifications:

  • ATC Clearances & Separation

    • ATC Facility:

    • Separation standards are applied and provided for all aircraft
    • Pilots must change their altimeter setting from the local altimeter to 29.92 when climbing through 18,000 feet
      • Setting 29.92 ensures all aircraft flying in Class A airspace have the same altimeter setting and will have proper altitude separation
    • Non-Reduced Vertical Separation Minima (RVSM) separation is 2,000' vertically
    • RVSM separation is 1,000' vertically

  • Jet & Q Routes:

    • Jet Routes and Q Routes
      High Altitude Enroute Chart

    • Jet Routes:

      • Within the cruise altitudes, there are Jet Routes, or "J" Routes, which are highways in the sky, much the same as Victor routes
      • Jet Routes begin at 18,000' MSL and end at Flight Level (FL) 450 (about 45,000')
      • The letter "J" precedes a number to label the airway
      • Note the range of Jet Routes is less than the dimensions of Class Alpha airspace [Figure 2]
        • Limited due to Standard Service Volume (SSV) of ground stations
      • Jet routes have no defined width
      • A Navigational Aid (NAVAID) on a continuing jet route is NOT part of the segment and is not to be included in your flight plan

    • Q Routes:

      • Q Routes are available for use by RNAV-equipped aircraft between 18,000' MSL and FL450 (about 45,000') inclusive, same as J Routes
      • Enroute High Altitude Charts depict Q Routes [Figure 2]
        • Operation above FL450 (about 45,000') are permitted on a point-to-point basis
      • Area navigation (RNAV) routes have been established in both the low-altitude and the high-altitude structures in recent years, depicted on the enroute low and high chart series
      • High-altitude RNAV routes are identified with a "Q" prefix (except the Q-routes in the Gulf of Mexico), and low-altitude RNAV routes are identified with a "T" prefix
      • RNAV routes and data are depicted in aeronautical blue
      • In addition to the published routes, a random RNAV route may be flown under IFR if it is approved by ATC
      • Random RNAV routes are direct routes, based on RNAV capability, between waypoints defined in terms of latitude/longitude coordinates, degree-distance fixes, or offsets from established routes/airways at a specified distance and direction
      • Radar monitoring by ATC is required on all random RNAV routes
      • Approval for these routes requires a radar environment
      • Factors that ATC considers in approving random RNAV routes include the capability to provide radar monitoring and compatibility with traffic volume and flow
      • ATC will radar monitor each flight; however, navigation on the random RNAV route is the responsibility of the pilot
    • Jet Routes and Q Routes
      High Altitude Enroute Chart

ATC Authorizations:

  • An operator may deviate from any provision of part 91.135 provided an ATC authorization issued by the ATC facility having jurisdiction of the airspace concerned
  • In the case of an inoperative transponder, ATC may immediately approve an operation within a Class A airspace area allowing the flight to continue, to the airport of ultimate destination, including any intermediate stops, or to proceed to a place where suitable repairs can be made, or both
  • Requests for deviation from any provision of this section must be submitted in writing at least four days before the proposed operation
    • ATC may authorize a deviation continuously or for an individual flight

Conclusion:


References: