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Class Delta Airspace

Introduction:

  • Class Delta (Class D) airspace is generally established around airports that have an operating control tower but do not provide radar services, as in Class Bravo or Charlie airspace
  • Class D airspace supports both Instrument Flight Rules (IFR) and Visual Flight Rules (VFR) operations within
  • At those airports where the control tower does not operate 24 hours a day, the operating hours of the tower will be listed on the appropriate charts and the Airport/Facility Directory (A/FD)
    • During the hours the tower is not in operation, the Class E surface area rules or a combination of Class E rules to 700' above the ground level and Class G rules to the surface will become applicable
  • The primary airport is always the airport for which the Class D airspace area is designated whereas the satellite airport is any other airport within the Class D airspace area
Airspace Dimensions
Figure 1: General Airspace Overview
Satellite Airspace Exclusions
Figure 2: Satellite Airspace Exclusions

Airspace Dimensions:

  • The configuration of each Class D airspace area is individually tailored to:
    1. Contain the intended operations;
    2. Allow for safe and efficient handling of operations, and;
    3. When instrument procedures are published, contain IFR arrival operations while between the surface and 1,000 feet above the surface and IFR departure operations while between the surface and the base of adjacent controlled airspace
      • Arrival extensions for instrument approach procedures (IAPs) may be Class D or Class E airspace
      • If all extensions are 2 miles or less, they generally remain part of the Class D surface area
      • If any one extension is greater than 2 miles, then all extensions become Class E
  • Horizontal Limits:

    • Class D areas are tailored to the area, but 5 SM (4.4 NM) standard radius surrounding those airports that have an operational control tower
  • Vertical Limits:

    • Class D areas should normally extend upward from the surface up to and including 2,500 feet AGL
    • In a low density or non-turbo aircraft traffic environment, a vertical limit of 2,500 feet AGL may be excessive and a lower altitude should be used
  • The size of a Class D area, and any necessary extensions, is determined by the use of a 200 feet per NM climb gradient and information obtained from the person responsible for developing instrument procedures [Figure 2]
    • Normally, the person responsible for developing instrument procedures for civil and U.S. Army airports is a FAA Aviation Standards Airspace Evaluation Specialist
    • A military representative handles all other military procedures
  • Generally, separate Class D airspace areas will be established for airports in proximity to each other so as to eliminate satellite airports as practical [Figure 3]
    Sectional Chart Class Delta Airspace Depiction
    Figure 3: Sectional Chart
    Class Delta Airspace Depiction
    • A common boundary line must be used so that the airspace areas do not overlap
    • When operationally advantageous, the common boundary separating adjacent Class D areas may be eliminated if the areas are contained in an existing Class B or Class C airspace area controlled by the same IFR ATC facility

Airspace Depiction:

  • On Sectional and Terminal charts Class D airspace areas are depicted with blue segmented lines [Figure 3]
    • The number in brackets inside the depicted airspace shows the altitude (MSL) of the airspace in hundreds of feet
      • If the number is preceded by a minus (-) then it indicates "from surface to, but not including" what is shown
    • The primary airport is indicated by a blue symbol
  • On IFR En Route Lows Class D is only recognized by a boxed [D] in the airport information [Figure 4]

ATC Facility:

  • Air Traffic Control Tower (ATCT):
    • Also known as "tower"
    • Provides takeoff, landing, and sometimes taxi clearance (at small airports, ground and tower are the same person)
    • No person may, at any airport with an operating control tower, operate an aircraft on a runway or taxiway, or takeoff or land an aircraft, unless an appropriate clearance is received from ATC
    • 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

IFR Enroute Chart Class Delta Airspace Depiction
Figure 4: IFR Enroute Chart
Class Delta Airspace Depiction

VFR Visibility Requirements:

  • 3 SM visibility, 500' below, 1,000' above, 2,000' horizontal
  • Under Special VFR, if granted by the controller, a pilot may enter or leave Class D Airspace in 1 statute mile of visibility while remaining clear of clouds

Operating Rules and Pilot/Equipment Requirements:

  • Pilot Certification: Student pilot or better
  • Equipment: Unless otherwise authorized by ATC, an operable two-way radio is required
  • Arrival or Through Flight Entry Requirements:
    Sectional Chart Class Delta Airspace
    Figure 4: Joe Williams (KNJW) Class Delta Airspace
    • Two-way radio communication (either direct or rapid relay through other facilities which are acceptable to the ATC facility) must be established with the ATC facility providing ATC services, on the publicized frequency, prior to entry and thereafter maintain those communications while in the Class D airspace
    • Calls should be initiated far enough from the Class D airspace boundary to preclude entering before two-way communications are established
      • Pilot: "[Tower], [Callsign], [Position], [Altitude], [Destination], [ATIS Information] [Request(s)/Intention(s)]"
      • Example: "Montgomery Tower, Cessna 1727V, 10 miles to the west, five thousand feet inbound to Montgomery, information Quebec request touch and goes"
    • Two-way radio communications is established when the pilot hears their callsign in response to their call
      • ATC: "[Callsign], [Tower], [Altimeter], [Instructions]"
      • Example: "Cessna 1727V, Montgomery Tower, altimeter 30.03, report 3 mile left base for runway 36"
      • Example: "Cessna 1727V, standby"
      • Example: "Cessna 1727V, remain outside the Class Delta airspace and standby"
    • It is important to understand that if the controller responds to the initial radio call without using the aircraft callsign, radio communications have not been established and the pilot may not enter the Class D airspace
      • ATC: "Aircraft calling, standby"
    • If workload or traffic conditions prevent immediate entry into Class D airspace, the controller will inform the pilot to remain outside the Class D airspace until conditions permit entry
      • ATC: "Aircraft calling, remain outside Class Delta airspace and standby"
    • At those airports where the control tower does not operate 24 hours a day, the operating hours of the tower will be listed on the appropriate charts and in the A/FD. During the hours the tower is not in operation, the Class E surface area rules or a combination of Class E rules to 700' AGL and Class G rules to the surface will become applicable. Check the A/FD for specifics
  • Departures from:
    • From the primary airport or satellite airport with an operating control tower, the pilot must establish and maintain two-way radio communications with the control tower, and thereafter as instructed by ATC while operating in the Class D airspace area
    • From a satellite airport without an operating control tower, the pilot must establish and maintain two-way radio communications with the ATC facility having jurisdiction over the Class D airspace area as soon as practicable after departing
    • Each pilot must comply with any departure procedures established for that airport by the FAA
  • Unless otherwise required by the prescribed departure procedure for that airport or the applicable distance from clouds criteria, each pilot of a turbine-powered airplane and each pilot of a large airplane must climb to an altitude of 1,500' above the surface as rapidly as practicable

Aircraft Separation:

  • IFR, SVFR, and runway operations
  • NO separation provided for VFR operations

Restrictions:

  • Arrival extensions for IAPs may be Class Delta or Echo airspace
    • As a general rule, if all extensions are 2 miles or less, they remain part of Class D; however, if any one extension is greater than 2 miles, then all extensions become Class E
  • Unless required by the applicable distance-from-cloud criteria, each pilot operating a large or turbine-powered airplane must enter the traffic pattern at an altitude of at least 1,500' above the elevation of the airport and maintain at least 1,500' until further descent is required for a safe landing
  • Speed:
    • Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500' AGL within 4 NM of the primary airport of a Class D airspace area at an indicated airspeed of more than 200 knots (230 mph)
    • Arrival extensions for instrument approach procedures may be Class D or Class E airspace
    • As a general rule of thumb:
      • If all extensions are 2 miles or less, they remain part of the Class D surface area
      • If any one extension is greater than 2 miles, then all extensions become Class E

Weather Observations and Reporting

  • Weather observations must be taken at the primary airport during the times and dates the Class D airspace is active by either a federally certified weather observer or a federally commissioned automated weather observing system
    • This includes all FAA and NWS approved and certified weather reporting systems
  • The weather observer must take routine (hourly) and special observations, called METARs
  • An automated weather observing system can provide continuous weather observations, called AWOS/ASOS
  • Scheduled record and special observations from weather observers or automated weather reporting systems must be made available to the ATC facility(s) having control jurisdiction over the Class D designated surface area
  • This can be accomplished through Flight Service Station (FSS), Longline Dissemination, National Weather Service (NWS), or other FAA-approved sources
  • Facilities that require weather reports from satellite airports may enter into a letter of agreement (LOA) with the associated FSS, airline/contract observer, airport management, etc.
    • At ATC sites where non-Federal employees perform weather duties, the appropriate FAA office must ensure that the reporting and dissemination requirements applicable to National Weather Service and FAA publication standards are followed
    • In facilities where direct access to automated weather observing systems is not available, controllers will apply the provisions of FAAO 7110.65, Air Traffic Control
  • Should these services be unavailable, a NOTAM will be issued

Sectional Charts
Figure 5: Sectional Charts

Notes:

  • When the tower is not in operation, the airspace reverts to Class Golf, or a combination of Class Echo and Golf airspace
  • When operating out of a satellite airport, contact tower for arrival and departures as soon as practicable
  • Turbine aircraft will operate at 1,500' AGL in the pattern until in a position to make a safe landing
  • Circle to the left and avoid the flow of fixed wing traffic if operating a helicopter
  • On departure, turbine aircraft must climb to 1,500' as rapidly as practical
  • Comply with all noise abatement, found in the Airport/Facility Directory (A/FD)
  • Each pilot operating a large or turbine-powered airplane approaching to land on a runway served by an instrument approach procedure with vertical guidance, if the airplane is so equipped, must:
    • Operate that airplane at an altitude at or above the glide path between the published final approach fix and the decision altitude (DA), or decision height (DH), as applicable; or
    • If compliance with the applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at or above the glide path, between the point of interception of glide path and the DA or the DH
  • Each pilot operating an airplane approaching to land on a runway served by a visual approach slope indicator must maintain an altitude at or above the glide path until a lower altitude is necessary for a safe landing
  • Nothing prohibits normal bracketing maneuvers above or below the glide path that are conducted for the purpose of remaining on the glide path
  • Except when conducting a circling approach under part 97 of this chapter or unless otherwise required by ATC, each pilot must:
    • Circle the airport to the left, if operating an airplane; or
    • Avoid the flow of fixed-wing aircraft, if operating a helicopter
  • Where a formal runway use program has been established by the FAA, each pilot of a large or turbine-powered airplane assigned a noise abatement runway by ATC must use that runway. However, consistent with the final authority of the pilot in command concerning the safe operation of the aircraft as prescribed in 91.3(a), ATC may assign a different runway if requested by the pilot in the interest of safety
  • If two-way radio communications are lost during operations inside of class Delta airspace, follow the appropriate lost communication procedures

Conclusion:

  • Not all airports with an operating control tower will have Class D airspace (Lake City Gateway, FL)
    • These airports do not have weather reporting which is a requirement for surface based controlled airspace
  • Unless otherwise authorized or required by the Air Traffic Control (ATC) facility having jurisdiction over the Class D airspace area, each person operating an aircraft in Class D airspace must comply with the applicable provisions of FAR 91.129
  • Additionally tools are available to better increase your knowledge of airspace including The Navigation CD-ROM and/or Using Aeronautical Charts by Terry Lankford eBook

References: