32.
IFR Separation Standards
32.1 ATC effects separation of aircraft vertically by assigning different altitudes; longitudinally by providing an interval expressed in time or distance between aircraft on the same, converging, or crossing courses; and laterally by assigning different flight paths.
32.2 Separation will be provided between all aircraft operating on IFR flight plans except during that part of the flight (outside Class B airspace or a TRSA) being conducted on a VFR.on.top/VFR conditions clearance. Under these conditions, ATC may issue traffic advisories, but it is the sole responsibility of the pilot to be vigilant so as to see and avoid other aircraft.
32.3 When radar is employed in the separation of aircraft at the same altitude, a minimum of 3 miles separation is provided between aircraft operating within 40 miles of the radar antenna site, and 5 miles between aircraft operating beyond 40 miles from the antenna site. These minimums may be increased or decreased in certain specific situations.
NOTE.
Certain separation standards are increased in the terminal environment when Center Radar Arts Presenta-tion/Processing (CENRAP) is being utilized.
33. Speed Adjustments
33.1 ATC will issue speed adjustments to pilots of radar.controlled aircraft to achieve or to maintain required or desired spacing.
33.2 ATC will express all speed adjustments in terms of knots based on indicated airspeed (IAS) in 10.knot increments except that at or above FL 240 speeds may be expressed in terms of Mach numbers in .01 increments. The use of Mach numbers is restricted to turbojet aircraft with Mach meters.
33.3 Pilots of aircraft in U.S. domestic Class A, B, C, D, and E airspace complying with speed adjustments should maintain a speed within plus or minus 10 knots or 0.02 Mach number, whichever is less, of the assigned speed.
33.4 Pilots of aircraft in offshore controlled airspace or oceanic controlled airspace shall adhere to the ATC assigned airspeed and shall request ATC approval before making any change thereto. If it is essential to make an immediate temporary change in the Mach number (e.g., due to turbulence), ATC shall be notified as soon as possible. If it is not feasible to maintain the last assigned Mach number during an en route climb or descent due to aircraft performance, advise ATC at the time of the request.
33.5 When ATC assigns speed adjustments, it will be in accordance with the following recommended minimums:
33.5.1 To aircraft operating between FL 280 and 10,000 feet, a speed not less than 250 knots or the equivalent Mach number.
NOTE.
1.
On a standard day the Mach numbers equivalent to 250 knots CAS (subject to minor variations) are: FL 240.0.6 FL 250.0.61 FL 260.0.62 FL 270.0.64 FL 280.0.65 FL 290.0.66.
2.
When an operational advantage will be realized, speeds lower than the recommended minima may be applied.
33.5.2 To arriving turbojet aircraft operating below 10,000 feet, a speed not less than 210 knots, except within 20 flying miles of the airport of intended landing, a speed not less than 170 knots.
33.5.3 To arriving reciprocating engine or turboprop aircraft within 20 flying miles of the runway threshold of the airport of intended landing, a speed not less than 150 knots.
33.5.4 Departures, for turbojet aircraft, a speed not less than 230 knots; for reciprocating engine aircraft, a speed not less than 150 knots.
33.6 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; i.e., “DESCEND AND MAINTAIN (altitude); THEN, REDUCE SPEED TO (speed),” or “REDUCE SPEED TO (speed); THEN, DESCEND AND MAINTAIN (altitude).”
NOTE.
The maximum speeds below 10,000 feet as established in 14 CFR Section 91.117 still apply. If there is any doubt concerning the manner in which such a clearance is to be executed, request clarification from ATC.
33.7 If ATC determines (before an approach clearance is issued) that it is no longer necessary to apply speed adjustment procedures, they will inform the pilot to resume normal speed. Approach clearances supersede any prior speed adjustment assignments, 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 final approach fix on final or a point 5 miles from the runway, whichever is closer to the runway.
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