Aircraft Speed

Introduction:

  • Same as you have speed limits on the road, they exist in the sky
  • Their purposes is to facilitate the most safe and efficient flow of traffic, especially in the low altitude and terminal structure

Civil Speed Regulations:

  • Unless otherwise authorized by the administrator, no person may operate an aircraft below 10,000' MSL at an indicated airspeed of more than 250 knots (288 mph)
  • Unless otherwise authorized by ATC, no person may operate an aircraft at or below 2,500' MSL within 4 NM of the primary airport of class C or D airspace at an indicated airspeed of more than 200 knots (230 mph)
  • No person may operate an aircraft in the airspace underlying a class B airspace area designated for an airport or in a VFR corridor designated through such a class B airspace area, at an indicated airspeed of more than 200 knots (230 mph)
    • However, inside of class B aircraft below 10,000' MSL are authorized to fly in excess of 200 knots but no more than 250 knots
  • If the minimum safe airspeed for any particular operation is greater than the maximum prescribed speed, the aircraft may be operated at that minimum speed

Speed Adjustments:

  • When ATC combines a speed adjustment with a descent clearance, the sequence of delivery, with the word "then" between, indicates the expected order of execution
    • ATC: "Descend and maintain [altitude]; then, reduce speed to [speed]"
    • ATC: "Reduce speed to [speed]; then, descend and maintain [altitude]"
  • Approach clearances supersede any prior speed adjustments, and pilots are expected to make their own speed adjustments, as necessary to complete the approach
  • Under certain circumstances, however, it may be necessary for ATC to issue further speed adjustments after approach clearance is issued to maintain separation between successive arrivals
    • Under such circumstances, previously issued speed adjustments will be restated if that speed is to be maintained or additional speed adjustments are requested
    • ATC must obtain pilot concurrence for speed adjustments after approach clearances are issued
    • Speed adjustments should not be assigned inside the FAF on final or a point 5 miles from the runway, whichever is closer to the runway
      • "Resume normal speed" does not delete speed restrictions that are contained in a published procedure unless specified
  • The pilots retain the prerogative of rejecting the application of speed adjustment by ATC if the minimum safe airspeed for any particular operation is greater than the sped adjustment
  • Pilots are reminded that they are responsible for rejecting the application of speed adjustments by ATC if, in their opinion, it will cause them to exceed the maximum indicated airspeed prescribed by 91.117(a),(c) and (d)
    • Inform ATC if unable to comply
  • Pilots operating at or above 10,000' MSL who are issued speed adjustments which exceed 250 knots IAS and are subsequently cleared below 10,000' MSL are expected to comply with FAR 91.117(a)
  • Speed restrictions of 250 knots do not apply to U.S. Registered aircraft operating beyond 12 nm from the coastline within the U.S. Flight Information Region, in Class E airspace below 10,000' MSL
    • However, in airspace underlying a Class B airspace area, pilots are expected to comply with the 200 knot speed limit in FAR 91.117(c) 200 KIAS (230 MPH)
  • For operations in a Class C and Class D surface area, ATC is authorized to request or approve a speed greater than the maximum indicated airspeeds prescribed for operation within that airspace in FAR 91.117(b) 200 KIAS (230 MPH)
  • When communications with ARTCC or approach control facility, pilots should, as a good operating practice, state any ATC assigned speed restriction on initial radio contact associated with an ATC communications frequency change

Responsibilities:

  • Pilot Responsibilities:

    • Advises ATC any time cruising airspeed varies plus or minus 5% or 10 knots, whichever is greater from that given in the flight plan
    • Complies with speed adjustments from ATC unless:
      • The minimum or maximum safe airspeed for any particular operation is greater or less than the requested airspeed
        • It is the pilot's responsibility and prerogative to advise ATC of, and refuse, speed adjustments considered excessive or contrary to the aircraft's operating specifications
      • Operating at or above 10,000 feet MSL on an ATC assigned SPEED ADJUSTMENT of more than 250 knots IAS and subsequent clearance is received for descent below 10,000 feet MSL
        • In such cases, pilots are expected to comply with 14 CFR Section 91.117(a)
    • When complying with speed adjustment assignments, maintains an indicated airspeed within plus or minus 10 knots or 0.02 Mach number of the specified speed

  • Controller Responsibilities:

    • Assigns speed adjustments to aircraft when necessary but not as a substitute for good vectoring technique
    • Adheres to the restrictions published in FAA Order JO 7110.65, Air Traffic Control, as to when speed adjustment procedures may be applied
    • Avoids alternating increase and decreasing airspeeds
    • Assigns speed adjustments to a specified IAS (KNOTS)/Mach number or to increase or decrease speed using increments of 5 knots or multiples thereof
    • Terminates ATC-assigned speed adjustments when no longer required by issuing further instructions to pilots in the following manner:
      • Advises pilots to "resume normal speed" when the aircraft is on a heading, random routing, charted procedure, or route without published speed restrictions
      • Instructs pilots to "comply with speed restrictions" when the aircraft is joining or resuming a charted procedure or route with published speed restrictions
        • CAUTION-The phraseology "Climb via SID" requires compliance with all altitude and/or speed restrictions depicted on the procedure
      • Instructs pilots to "resume published speed" when aircraft are cleared via a charted instrument flight procedure that contains published speed restrictions
      • Advises aircraft to "delete speed restrictions" when ATC assigned or published speed restrictions on a charted procedure are no longer required
      • Clears pilots for approach without restating previously issued speed adjustments
    • Gives due consideration to aircraft capabilities to reduce speed while descending
    • Does not assign speed adjustments to aircraft at or above FL 390 without pilot consent

Airspace Speed Restrictions:

  • Depending on the type of airspace in which you operate, speed limits do apply

  • Class Alpha Airspace:

  • Class Bravo Airspace:

    • No speed restriction inside class bravo airspace when above 10,000 ft
    • 250 knots inside of class bravo airspace, when below 10,000 ft
    • Descents below 10,000 ft, require speed reduction to 250 knots, regardless of prior assignments
    • 200 knots under the airspace or in a corridor
    • Speed of 250 knots must not be exceeded, even if you are told to "maintain best forward speed"

  • Class Charlie Airspace:

    • 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 C airspace area at an indicated airspeed of more than 200 knots (230 mph)

  • Class Delta Airspace:

    • 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)

  • Class Echo Airspace:

    • 250 knots below 10,000' MSL within class echo airspace
    • While operating in the traffic pattern at an airport without an operating control tower, it is recommended that the pilot maintain an airspeed of no more than 200 KIAS

  • Class Golf Airspace:

Instrument Procedures:

  • When the approach procedure involves a procedure turn, a maximum speed of not greater than 200 knots (IAS) should be observed from first overheading the course reversal IAF through the procedure turn maneuver to ensure containment within the obstruction clearance area

Supersonic Flight Operations:

  • Commanding officers assigned aircraft capable of supersonic flight shall ensure that aircrews are thoroughly familiar with the shock wave phenomenon peculiar to supersonic flight. Serious damage, annoyance, and mental stress have resulted from sonic booms. It is incumbent on every pilot flying aircraft capable of generating sonic booms to reduce such disturbances and damage to the absolute minimum dictated by operational/training requirements

  • Policy:
    • Supersonic flight operations shall be strictly controlled and supervised by operational commanders. Supersonic flight over land or within 30 miles offshore shall be conducted in specifically designated areas. Such areas must be chosen to ensure minimum possibility of disturbance. As a general policy, sonic booms shall not be intentionally generated below 30,000' of altitude unless over water and more than 30 miles from inhabited land areas or islands. Deviations from the foregoing general policy may be authorized only under one of the following:
      • Tactical missions that require supersonic speeds
      • Phases of formal training syllabus flights requiring supersonic speeds
      • Research, test, and operational suitability test flights requiring supersonic speeds
      • When specifically authorized by CNO for flight demonstration purposes
  • Reports, Inquiries, and Investigations:
    • The Department of the Navy must accept responsibility for restitution and payment of just claims for damage resulting from sonic booms determined to have been caused by naval aircraft
    • To assist in determining validity of claims, all supersonic flights conducted over the CONUS or within 50 miles offshore shall be logged as to time, date, location, speed, and altitude of occurrence and retained at the unit level for 24 months
    • Section 0910f of reference (r) provides information and instructions concerning investigations into sonic boom complaints and alleged damage claims

Small Unmanned Aircraft Systems Speed Limitations:

  • The groundspeed of the small unmanned aircraft may not exceed 87 knots (100 miles per hour)

Conclusion:

  • Controller regulations are published in FAA Order JO 7110.65, Air Traffic Control, as to when speed adjustment procedures may be applied
  • Note that when ATC askes for airspeed, its always in reference to indicated airspeed
  • Under rare instances (such as military fighters), if the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed. Note: There is no requirement to advise ATC when exceeding a speed for this reason
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