4-5-1 Vertical Separation Minima

 Separate instrument flight rules (IFR) aircraft using the following minima between altitudes:
  a. Up to and including FL 290 - 1,000 feet.
  b. Above FL 290 - 2,000 feet, except
   1. In oceanic airspace, above FL 450 between a supersonic and any other aircraft - 4,000 feet.
   2. Above FL 600 between military aircraft - 5,000 feet.

{New-98-8 Revised August 13, 1998}

   3. Apply 1,000 feet between approved aircraft if:
    (a) Operating within airspace and altitude(s) designated for reduced vertical separation minimum (RVSM) or,
    (b) Operating within RVSM transition airspace and designated altitude(s) if en route to/from RVSM designated airspace.

{New-98-8 Revised August 13, 1998}

 NOTE -
  1 - Oceanic separation procedures are supplemented in Chapter 8, Section 7, Section 8, Section 9, and Section
   10.
  2 - RVSM and RVSM transition airspace is designated in ICAO Regional Supplementary Document, Doc.
   7030.4, and via International NOTAM.

REFERENCE -
FAAO 7110.65, Vertical Application, paragraph 5-5-4.
FAAO 7110.65, Application, paragraph 6-6-1.
FAAO 7110.65, Military Operations Above FL 600, paragraph 9-3-11.

4-5-2 Flight Direction

 Clear aircraft at altitudes according to the Table 4-5-1.

                   Table 4-5-1 - Altitude Assignment
   ----------------------------------------------------------------
   AIRCRAFT OPERATING: Below 3,000 feet above surface
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Any altitude
   ----------------------------------------------------------------
   AIRCRAFT OPERATING: Below FL 290

   ON COURSE DEGREES MAGNETIC: 0 through 179
   ASSIGN: Odd cardinal altitudes or flight levels at
           intervals of 2,000 feet.
   EXAMPLES: 3,000, 5,000, FL 250, FL 270

   ON COURSE DEGREES MAGNETIC: 180 through 359
   ASSIGN: Even cardinal altitude or flight levels at
           intervals of 2,000 feet.
   EXAMPLES: 4,000, 6,000, FL 240, FL 260
   -----------------------------------------------------------------
   AIRCRAFT OPERATING: At or above FL 290

   ON COURSE DEGREES MAGNETIC: 0 through 179
   ASSIGN: Odd cardinal flight levels at intervals
           of 4,000 feet beginning with FL 290
   EXAMPLES: FL 290, FL 330, FL 370

   ON COURSE DEGREES MAGNETIC: 180 through 359
   ASSIGN: Odd cardinal flight levels at intervals
           of 4,000 feet beginning with FL 310
   EXAMPLES: FL 310, FL 350, FL 390
   -----------------------------------------------------------------
   AIRCRAFT OPERATING: One way routes (except in composite systems)
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Any cardinal altitude or flight level
           below FL 290 or any odd cardinal flight level
           at or above FL 290
   EXAMPLES: FL 270, FL 280, FL 310, FL 330
   -----------------------------------------------------------------
   AIRCRAFT OPERATING: Within an ALTRV
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Any altitude or flight level
   -----------------------------------------------------------------
   AIRCRAFT OPERATING: In transition to/from or within Oceanic
                       airspace where composite separation is authorized
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Any odd or even cardinal flight level
           including those above FL 290
   EXAMPLES: FL 280, FL 290, FL 300, FL 310, FL 320, FL 330, FL 340
   -----------------------------------------------------------------
   AIRCRAFT OPERATING: In aerial refueling tracks and anchors
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Altitude blocks as requested. Any altitude or flight level
   EXAMPLES: 050B080, FL180B220, FL280B310
   ------------------------------------------------------------------------------------------

{New-98-8 Revised August 13, 1998}

   AIRCRAFT OPERATING: Approved Aircraft within RVSM or RVSM
                       transition airspace
   ON COURSE DEGREES MAGNETIC: Any course
   ASSIGN: Any designated cardinal altitude
   EXAMPLES: FL330, FL340, FL350, FL360
 ---------------------------------------------------------------------

NOTE -
Oceanic separation procedures are supplemented in Chapter 8, Section 7, Section 8, Section 9, and Section 10.

REFERENCE -
FAAO 7110.65, Exceptions, paragraph 4-5-3.
FAAO 7110.65, Altitude Assignments, paragraph 7-7-5.
FAAO 7110.65, Separation Minima, paragraph 9-4-2.

4-5-3 Exceptions

 When traffic, meteorological conditions, or aircraft operational limitations prevent assignment of altitudes prescribed in paragraph 4-5-2, Flight Direction, assign any cardinal altitude or flight level below FL 290 or any odd cardinal flight level at or above FL 290 without regard to direction of flight as follows:

NOTE -
See paragraph 2-3-9, Control Symbology, for control abbreviations and symbols to be used in conjunction with this paragraph.
 a. For traffic conditions, take this action only if one of the following conditions exists:
  1. Aircraft remain within a facility's area and prior approval is obtained from other affected positions or sectors or the operations are covered in a Facility Directive.
  2. Aircraft will proceed beyond the facility's area and specific operations and procedures permitting random altitude assignment are covered in a letter of agreement between the appropriate facilities.

NOTE -
Those en route facilities using HOST software that provides capability for passing interim altitude shall include the specific operations and procedures for use of this procedure in a letter of agreement between the appropriate facilities.
 b. Military aircraft are operating on random routes and prior approval is obtained from the facility concerned.
 c. For meteorological conditions, take this action only if you obtain prior approval from other affected positions or sectors within your facility and, if necessary, from the adjacent facility concerned.
 d. For aircraft operational limitations, take this action only if the pilot informs you the available appropriate altitude exceeds the operational limitations of his aircraft and only after you obtain prior approval from other affected positions or sectors within your facility and, if necessary, from the adjacent facility concerned.
 e. For mission requirements, take this action only when the aircraft is operating on an MTR.

REFERENCE -
FAAO 7110.65, Altitude Assignments, paragraph 7-7-5.
FAAO 7110.65, Separation Minima, paragraph 9-4-2.

4-5-4 Lowest Usable Flight Level

 If a change in atmospheric pressure affects a usable flight level in your area of jurisdiction, use Table 4-5-2 to determine the lowest usable flight level to clear aircraft at or above 18,000 feet MSL.

                Table 4-5-2
              Lowest Usable FL
   --------------------------------------
    Altimeter Setting          Lowest Usable FL
   --------------------------------------
    29.92" or higher                180
    29.91" to 28.92"               190
    28.91" to 27.92"               200
   --------------------------------------

REFERENCE -
FAAO 7110.65, Separation Minima, paragraph 9-4-2.

4-5-5 Adjusted Minimum Flight Level

 When the prescribed minimum altitude for IFR operations is at or above 18,000 feet MSL and the atmospheric pressure is less than 29.92", add the appropriate adjustment factor from Table 4-5-3 to the flight level equivalent of the minimum altitude in feet to determine the adjusted minimum flight level.

                Table 4-5-3
           Minimum FL Adjustment
   ---------------------------------------
    Altimeter Setting        Adjustment Factor
   ---------------------------------------
     29.92" or higher            None
     29.91" to 29.42"           500 feet
     29.41" to 28.92"           1,000 feet
     28.91" to 28.42"           1,500 feet
     28.41" to 27.92"           2,000 feet
   ---------------------------------------

4-5-6 Minimum En route Altitudes

 Except as provided in subparagraphs a and b below, assign altitudes at or above the MEA for the route segment being flown. When a lower MEA for subsequent segments of the route is applicable, issue the lower MEA only after the aircraft is over or past the Fix/NAVAID beyond which the lower MEA applies unless a crossing restriction at or above the higher MEA is issued.
 a. An aircraft may be cleared below the MEA but not below the MOCA for the route segment being flown if the altitude assigned is at least 300 feet above the floor of controlled airspace and one of the following conditions are met:

NOTE -
Controllers must be aware that in the event of radio communications failure, a pilot will climb to the MEA for the route segment being flown.
  1. Nonradar procedures are used only within 22 miles of a VOR, VORTAC, or TACAN.
  2. Radar procedures are used only when an operational advantage is realized and the following actions are taken:
   (a) Radar navigational guidance is provided until the aircraft is within 22 miles of the NAVAID, and
   (b) Lost communications instructions are issued.
 b. An aircraft may be cleared to operate on jet routes below the MEA (but not below the prescribed minimum altitude for IFR operations) or above the maximum authorized altitude if, in either case, radar service is provided.

NOTE -
Minimum en route and maximum authorized altitudes for certain jet route segments have been established above the floor of the jet route structure due to limitations on navigational signal coverage.
 c. Where a higher altitude is required because of an MEA, the aircraft shall be cleared to begin climb to the higher MEA as follows:

  1. If no MCA is specified, prior to or immediately after passing the fix where the higher MEA is designated. (See Figure 4-5-1)   2. If a MCA is specified, prior to the fix so as to cross the fix at or above the MCA. (See Figure 4-5-2)
 

 d. Where MEAs have not been established, clear an aircraft at or above the minimum altitude for IFR operations prescribed by FAR Part 91.177.

REFERENCE -
FAAO 7110.65, IFR-VFR and VFR-IFR Flights, paragraph 4-2-8.
FAAO 7110.65, Route Use, paragraph 4-4-1.
FAAO 7110.65, Application, paragraph 5-6-1.
FAAO 7110.65, Altitude Assignments, paragraph 7-7-5.

4-5-7 Altitude Information

 Issue altitude instructions as follows:

REFERENCE -
FAAO 7110.65, Clearance Items, paragraph 4-2-1.
 a. Altitude to maintain or cruise. When issuing cruise in conjunction with an airport clearance limit and an unpublished route will be used, issue an appropriate crossing altitude to ensure terrain clearance until the aircraft reaches a fix, point, or route where the altitude information is available to the pilot. When issuing a cruise clearance to an airport which does not have a published instrument approach, a cruise clearance without a crossing restriction may be issued.

PHRASEOLOGY -
MAINTAIN/CRUISE (altitude). MAINTAIN (altitude) UNTIL (time),
   or
PAST (fix),
   or
(number of miles or minutes) MILES/MINUTES PAST (fix).
CROSS (fix, point)
   or
INTERCEPT (route) AT OR ABOVE (altitude), CRUISE (altitude).
NOTE -
1 - The crossing altitude must assure IFR obstruction clearance to the point where the aircraft is established on a segment of a published route or instrument approach procedure.
2 - When an aircraft is issued a cruise clearance to an airport which does not have a published instrument approach procedure, it is not possible to satisfy the requirement for a crossing altitude that will ensure terrain clearance until the aircraft reaches a fix, point, or route where altitude information is available to the pilot. Under those conditions, a cruise clearance without a crossing restriction authorizes a pilot to determine the minimum IFR altitude as prescribed in FAR Part 91.117 and descend to it at pilot discretion if it is lower than the altitude specified in the cruise clearance.
 b. Instructions to climb or descend including restrictions, as required. Specify a time restriction reference the UTC clock reading with a time check. If you are relaying through an authorized communications provider, such as ARINC, FSS, etc., advise the radio operator to issue the current time to the aircraft when the clearance is relayed.

EXAMPLE -
[1] "United Four Seventeen, climb to reach one three thousand at two two one five.
 Time two two one one and one-quarter."
 The pilot is expected to be level at 13,000 feet at 2215 UTC.
[2] Through Relay - "Speedbird Five, climb to reach flight level three-five zero at one-two-one-five, time" (Issue a time check).

REFERENCE -
FAAO 7110.65, Word Meaning, paragraph 1-2-1.
FAAO 7110.65, Numbers Usage, paragraph 2-4-17.

PHRASEOLOGY -
CLIMB/DESCEND AND MAINTAIN (altitude).
If required,
AFTER PASSING (fix),
or
AT (time) (Time in hours, minutes, and nearest quarter minute.)
CLIMB/DESCEND TO REACH (altitude)
AT (time (issue time check) or fix)
or
AT (time). CLIMB/DESCEND AND MAINTAIN (altitude)
WHEN ESTABLISHED AT LEAST (number of miles or minutes) MILES/MINUTES PAST (fix) ON THE (NAVAID) (specified) RADIAL.
CLIMB/DESCEND TO REACH (altitude) AT (time or fix).
or
A POINT (number of miles) MILES (direction) OF (name of DME NAVAID).
Through Relay:
CLIMB TO REACH (altitude) AT (time) (issue a time check).
 c. Specified altitude over a specified fix.
PHRASEOLOGY -
CROSS (fix) AT (altitude).
CROSS (fix) AT OR ABOVE/BELOW (altitude).
 d. A specified altitude over a specified fix for that portion of a descent clearance where descent at pilot's discretion is permissible. At any other time it is practicable, authorize climb/descent at pilot's discretion.
PHRASEOLOGY -
CLIMB/DESCEND AT PILOT'S DISCRETION.
EXAMPLE -
"United Four Seventeen, descend and maintain six thousand."

NOTE -
 The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates specified in the AIM, Adherence to Clearance, paragraph 4-4-9 until reaching the assigned altitude of 6,000 feet.

EXAMPLE -
"United Four Seventeen, descend at pilot's discretion, maintain six thousand."

NOTE -
The pilot is authorized to conduct descent within the context of the term "at pilot's discretion" as described in the AIM.

EXAMPLE -
"United Four Seventeen cross Lakeview VOR at or above flight level two zero zero, descend and maintain six thousand."

NOTE -
The pilot is authorized to conduct descent "at pilot's discretion" until reaching Lakeview VOR. The pilot must comply with the clearance provision to cross the Lakeview VOR at or above FL 200, and after passing Lakeview VOR, the pilot is expected to descend at the rates specified in the AIM until reaching the assigned altitude of 6,000 feet.

EXAMPLE -
"United Four Seventeen, cross Lakeview VOR at and maintain six thousand."

NOTE -
The pilot is authorized to conduct descent "at pilot's discretion," but must comply with the clearance provision to cross Lakeview VOR at 6,000 feet.

EXAMPLE -
"United Four Seventeen, descend now to flight level two seven zero, cross Lakeview VOR at or below one zero thousand, descend and maintain six thousand."

NOTE -
The pilot is expected to promptly execute and complete descent to FL 270 upon receipt of the clearance. After reaching FL 270, the pilot is authorized to descend "at pilot's discretion" until reaching Lakeview VOR. The pilot must comply with the clearance provision to cross Lakeview VOR at or below 10,000 feet. After Lakeview VOR, the pilot is expected to descend at the rates specified in the AIM until reaching 6,000 feet.

NOTE -
1 - A descent clearance which specifies a crossing altitude authorizes descent at pilot's discretion for that portion of the flight to which the crossing altitude restriction applies.
2 - Any other time that authorization to descend at pilot's discretion is intended, it must be specifically stated by the controller.
3 - The pilot may need to know of any future restrictions that might affect the descent, including those that may be issued in another sector, in order to properly plan a descent at pilot's discretion.
4 - Controllers need to be aware that the descent rates in the AIM are only suggested and aircraft will not always descend at those rates.

REFERENCE -
P/CG term - Pilot's Discretion.
 e. When a portion of a climb/descent may be authorized at the pilot's discretion, specify the altitude the aircraft must climb/descend to followed by the altitude to maintain at the pilot's discretion.

PHRASEOLOGY -
CLIMB/DESCEND NOW TO (altitude), THEN CLIMB/DESCEND AT PILOT'S DISCRETION MAINTAIN (altitude).

EXAMPLE -
"United three ten, descend now to flight level two eight zero, then descend at the pilot's discretion maintain flight level two four zero."

NOTE -
1 - The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates specified in the AIM Section on ATC Clearances/Separations, Adherence to Clearances, paragraph 4-4-9, until reaching flight level 280. At that point, the pilot is authorized to continue descent to flight level 240 within the context of the term "at pilot's discretion" as described in the AIM.
2- Controllers need to be aware that the descent rates in the AIM are only suggested and aircraft will not always descend at those rates.
 f. When the "pilot's discretion" portion of a climb/descent clearance is being canceled by assigning a new altitude, inform the pilot that the new altitude is an "amended altitude."

EXAMPLE -
"American Eighty Three, amend altitude, descend and maintain flight level two six zero."

NOTE -
American Eighty Three, at flight level 280, has been cleared to descend at pilot's discretion to flight level 240. Subsequently, the altitude assignment is changed to flight level 260, therefore, pilot's discretion is no longer authorized.
 g. Altitude assignments involving more than one altitude.

PHRASEOLOGY -
MAINTAIN BLOCK (altitude) THROUGH (altitude).
 h. Instructions to vertically navigate on a STAR/FMSP with published restrictions.

PHRASEOLOGY -
DESCEND VIA (STAR, FMSP name and number).

EXAMPLE -
"Descend via the Mudde One Arrival"
"Cross JCT at flight level two four zero."
"Descend via the Coast Two Arrival."

NOTE -
Clearance to "descend via" authorizes a pilot's discretion descent to comply with published altitude and/or speed crossing restrictions. "Expect" altitudes/speeds are not considered STAR/FMSP crossing restrictions until verbally issued by ATC. Their used by pilots is for planning purposes or lost communications procedures.
  1. If it is necessary to assign a crossing altitude which differs from the STAR/FMSP altitude, emphasize the change to the pilot.

PHRASEOLOGY -
DESCEND VIA THE (STAR/FMSPO ARRIVAL EXCEPT (revised altitude information).

REFERENCE -
FAAO 7110.65, Clearance Information, paragraph 4-7-1 AIM, STARS/FMSPS, paragraph 5-4-1.
 i. When a pilot is unable to accept a clearance, issue revised instructions to ensure positive control and standard separation.

NOTE -
1 - CFR Part 91.123 states that a pilot is not allowed to deviate from an ATC clearance "that has been obtained...unless an amended clearance is obtained" (except when an emergency exists).
2 - A pilot is therefore expected to advise the controller if a clearance cannot be accepted when the clearance is issued. "We will try" and other such acknowledgements do not constitute pilot acceptance of an ATC clearance.
3 - Controllers are expected to issue ATC clearances which conform with normal operational capabilities for each aircraft and do not require "last minute" amendments to ensure standard separation.
4 - "Expedite" is not to be used in lieu of appropriate restrictions to ensure separation.

{New-98-3 Revised February 26, 1998}

 REFERENCE -
  FAAO 7110.65, Providing Assistance, paragraph 10-1-3.

4-5-8 Anticipated Altitude Changes

 If practicable, inform an aircraft when to expect climb or descent clearance or to request altitude change from another facility.

PHRASEOLOGY -
EXPECT HIGHER/LOWER ALTITUDE IN (number of miles or minutes) MILES/MINUTES,
   or
AT (fix). REQUEST ALTITUDE CHANGE FROM (name of facility).
   If required,
AT (time, fix, or altitude).

REFERENCE -
FAAO 7110.65, IFR Flight Progress Data, paragraph 2-2-6.

4-5-9 Altitude Confirmation - Nonradar

 a. Request a pilot to confirm assigned altitude on initial contact and when position reports are received unless:

NOTE -
For the purpose of this paragraph, "initial contact" means a pilot's first radio contact with each sector/position.
  1. The pilot states the assigned altitude, or
  2. You assign a new altitude to a climbing or descending aircraft, or
  3. TERMINAL:
   The aircraft was transferred to you from another sector/position within your facility (intrafacility).

PHRASEOLOGY -
(In level flight situations),
   VERIFY AT (altitude).
In climbing/descending situations,
   VERIFY ASSIGNED ALTITUDE (altitude).
 b. USA: Reconfirm all pilot altitude readbacks.

PHRASEOLOGY -
If altitude readback is correct,
   AFFIRMATIVE (altitude).
If altitude readback is not correct,
   NEGATIVE. CLIMB/DESCEND AND MAINTAIN (Altitude),
or
   NEGATIVE. MAINTAIN (altitude).
 

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