IFR aircraft are required to be separated from each other by approved radar or non-radar separation minima. When radar coverage does not go to the ground (Usually at non-towered airports), normal radar separation minima (3 miles) cannot be ensured. Therefore, non-radar separation is required (One in/One out rule). Only 1 IFR aircraft can operate into or out of the airport at a given time. Because of this rule, controllers are required to restrict IFR departures/arrivals into/out of these airports in order to achieve approved separation.
If the aircraft calls for an IFR clearance on the ground, give the standard IFR clearance, followed by the phrase "HOLD FOR RELEASE". It is considered a good operating practice to clear aircraft "AS FILED" instead of "VIA RADAR VECTORS" for the following reasons:
a. Because the aircraft was cleared "VIA RADAR VECTORS," they are required to receive some initial vector on departure. In most circumstances, non-towered airports are inside class G airspace. Section 5-6-1 states that you can only vector aircraft "In Class G airspace upon pilot request." Therefore, any heading that is given on departure needs to be issued so as to apply only within controlled airspace. PHRASEOLOGY - "WHEN ENTERING CONTROLLED AIRSPACE, FLY HEADING (degrees)"
b. The aircraft will have to be given a vector below the MVA. This is legal, but requires additional work on behalf of the controller in order to give a heading that complies with section 5-6-3 below.
5−6−3. VECTORS BELOW MINIMUM ALTITUDE
a. Except in en route automated environments in areas where more than 3 miles separation minima is required, you may vector a departing IFR aircraft, or one executing a missed approach, within 40 miles of the radar antenna and before it reaches the minimum altitude for IFR operations if separation from prominent obstacles shown on the radar scope is applied in accordance with the following:
1. If the flight path is 3 miles or more from the obstacle and the aircraft is climbing to an altitude at least 1,000 feet above the obstacle, vector the aircraft to maintain at least 3 miles separation from the obstacle until the aircraft reports leaving an altitude above the obstacle.
2. If the flight path is less than 3 miles from the obstacle and the aircraft is climbing to an altitude at least 1,000 feet above the obstacle, vector the aircraft to increase lateral separation from the obstacle until the 3 mile minimum is achieved or until the aircraft reports leaving an altitude above the obstacle.
b. At those locations where diverse vector areas (DVA) have been established, radar facilities may vector aircraft below the MVA/MIA within the DVA described in facility directives.
c. All of the above information/work can be avoided if the aircraft is cleared "AS FILED." This puts the responsibility of terrain/obstruction clearance on the pilot instead of the controller. When cleared "AS FILED" the pilot will depart via their own navigation on ODPs, Diverse Departures, or other procedures up to the MVA/MEA.
After the "HOLD FOR RELEASE" instruction has been given, and the readback was correct, instruct the pilot to "ADVISE THIS FREQUENCY NUMBER ONE FOR DEPARTURE, CHANGE TO ADVISORY FREQUENCY APPROVED." The pilot will then call for his IFR release.
When the aircraft calls for his IFR release, ensure no other IFR aircraft has been cleared on an approach to the airport, then give the release.
EXAMPLE - "RELEASED FOR DEPARTURE. CLEARANCE VOID IF NOT OFF IN 5 MINUTES. IF NOT OFF IN 5 MINUTES, ADVISE THIS FREQUENCY OF INTENTIONS WITHIN 10 MINUTES. CHANGE TO ADVISORY FREQUENCY APPROVED"
The aircraft will call in the climb to the assigned altitude. Radar identify the aircraft properly, (No rolling call from tower) then treat as a normal IFR departure.
4−3−4. DEPARTURE RESTRICTIONS, CLEARANCE VOID TIMES, HOLD FOR RELEASE, AND RELEASE TIMES
Assign departure restrictions, clearance void times, hold for release, or release times when necessary to separate departures from other traffic or to restrict or regulate the departure flow.
b. Hold For Release (HFR).
1. “Hold for release” instructions must be used when necessary to inform a pilot or a controller that a departure clearance is not valid until additional instructions are received.
PHRASEOLOGY−
(Aircraft identification) CLEARED TO (destination) AIRPORT AS FILED, MAINTAIN (altitude), and if required, (additional instructions or information).
HOLD FOR RELEASE
3. When conditions allow, release the aircraft as soon as possible.
PHRASEOLOGY−
(aircraft identification) RELEASED FOR DEPARTURE.
a. Clearance Void Times.
1. When issuing clearance void times at airports not served by control towers, provide alternative instructions requiring the pilots to advise ATC of their intentions no later than 30 minutes after the clearance void time if not airborne.
2. The facility delivering a clearance void time to a pilot must issue a time check. A void time issued using a specified number of minutes does not require a time check.
PHRASEOLOGY−
CLEARANCE VOID IF NOT OFF BY (clearance void time),
and if required,
IF NOT OFF BY (clearance void time), ADVISE (facility) NOT LATER THAN (time) OF INTENTIONS.
TIME (time in hours, minutes, and the nearest quarter minute).
or
CLEARANCE VOID IF NOT OFF IN (number of minutes) MINUTES
and if required,
IF NOT OFF IN (number of minutes) MINUTES, ADVISE (facility) OF INTENTIONS WITHIN (number of minutes) MINUTES.
If there are no IFR aircraft that have been released/cleared for an approach, issue the approach clearance as normal.
If a previous IFR aircraft has been released for departure, or cleared on an approach, the controller cannot clear the arrival for an approach. The aircraft must hold until the departure has been radar identified, or the previous arrival cancels IFR. Use the following sections when issuing holding instructions:
4−6−1. CLEARANCE TO HOLDING FIX
a. Clearance limit
b. Holding instructions.
2. When the assigned procedure or route being flown includes a charted pattern, you may omit all holding instructions except the charted holding direction and the statement “as published.” Always issue complete holding instructions when the pilot requests them.
PHRASEOLOGY− CLEARED TO (fix), HOLD (direction), AS PUBLISHED
c. EFC.
PHRASEOLOGY− EXPECT FURTHER CLEARANCE (time)
2. When holding is necessary, the phrase “delay indefinite” should be used when an accurate estimate of the delay time and the reason for the delay cannot immediately be determined.
PHRASEOLOGY− DELAY INDEFINITE, (reason if known), EXPECT FURTHER CLEARANCE (time). (After determining the reason for the delay, advise the pilot as soon as possible.)
4−6−4. HOLDING INSTRUCTIONS
When issuing holding instructions, specify:
a. Direction of holding from the fix/waypoint.
b. Holding fix or waypoint.
NOTE− The holding fix may be omitted if included at the beginning of the transmission as the clearance limit.
c. Radial, course, bearing, track, azimuth, airway, or route on which the aircraft is to hold.
d. Leg length in miles if DME or RNAV is to be used. Specify leg length in minutes if the pilot requests it or you consider it necessary.
e. Direction of holding pattern turns only if left turns are to be made, the pilot requests it, or you consider it necessary.
PHRASEOLOGY−
HOLD (direction) OF (fix/waypoint) ON (specified radial, course, bearing, track, airway, azimuth(s), or route.)
If leg length is specified,
(number of minutes/miles) MINUTE/MILE LEG.
If direction of turn is specified, LEFT/RIGHT TURNS.
After the previous departure has been radar identified, or the previous arrival cancels IFR, re-clear the aircraft to their destination airport, then issue an approach clearance. Once the aircraft is 5-10 miles from the airport, inform them of the following information:
4−2−10. CANCELLATION OF IFR FLIGHT PLAN
a. If necessary, before instructing an IFR aircraft arriving at an airport not served by an air traffic control tower or flight service station to change to the common traffic advisory frequency, provide the pilot with instructions on how to cancel his/her IFR flight plan.
PHRASEOLOGY− (Call sign) REPORT CANCELLATION OF IFR THIS FREQUENCY
b. Respond to a pilot’s cancellation of his/her IFR flight plan as follows:
PHRASEOLOGY− (Call sign) IFR CANCELLATION RECEIVED.
4−8−8. COMMUNICATIONS RELEASE
If an IFR aircraft intends to land at an airport not served by a tower or FSS, approve a change to the advisory service frequency when you no longer require direct communications.
PHRASEOLOGY− CHANGE TO ADVISORY FREQUENCY APPROVED.
6−4−2. MINIMA ON SAME, CONVERGING, OR CROSSING COURSES
d. When the conditions of subparas a, b, or c cannot be met...10 minutes between other aircraft.
Practically Speaking: 10 minutes of non-radar separation will always be a legal way to separate aircraft. When dealing with EFC times/restrictions, use the following rules to ensure non-radar separation:
Two arrivals: After the first aircraft has been cleared for an approach, instruct the second aircraft to hold and give an EFC that equals the first aircraft's ETA over the airport plus 10 minutes.
Departure released with an inbound: After the departure has been released, instruct the second aircraft to hold and give an EFC that equals the first aircraft's void time plus 10 minutes.
Arrival released with a departure: After the arrival has been released to advisory, instruct the departing aircraft who is number 1 to hold for release, and how long the expected delay will be (ETA of arrival aircraft plus 10 minutes). Do not release the departure until the arrival has cancelled IFR. PHRASEOLOGY - HOLD FOR RELEASE, EXPECT (time in hours and/or minutes) DEPARTURE DELAY.
Two departures: After the first departure has been released, instruct the second aircraft to hold for release, and how long the expected delay will be (Void time plus 10 minutes). Release the second departure after you have radar identified the first aircraft and validated that they are climbing above the second aircraft's initial altitude.
Anytime an aircraft is unresponsive/lost comms/doesn't cancel IFR follow the procedures outlined in 7110.65 10-4-1.
4−2−8. IFR−VFR AND VFR−IFR FLIGHTS
d. When VFR aircraft operating below the minimum altitude for IFR operations requests an IFR clearance and the pilot informs you, or you are aware, that they are unable to climb in VFR conditions to the minimum IFR altitude:
1. Before issuing a clearance, ask if the pilot is able to maintain terrain and obstruction clearance during a climb to the minimum IFR altitude.
PHRASEOLOGY− (Aircraft call sign), ARE YOU ABLE TO MAINTAIN YOUR OWN TERRAIN AND OBSTRUCTION CLEARANCE UNTIL REACHING (appropriate MVA/MIA/MEA/OROCA)
2. If the pilot is able to maintain their own terrain and obstruction clearance, issue the appropriate IFR clearance as prescribed in Para 4−2−1, Clearance Items, and Para 4−5−6, Minimum En Route Altitudes.
3. If the pilot states that they are unable to maintain terrain and obstruction clearance, instruct the pilot to maintain VFR and to state intentions.
Practically Speaking: First, radar identify the VFR aircraft who is requesting pop up IFR, then validate their altitude. If their current altitude is below the MVA/MIA, use the phraseology prescribed above in part 1. If the aircraft is above the MVA/MIA, issue the IFR clearance.
As of May 2024, all terminal facilities within the National Airspace System are complying with FAA Order JO 7110.126, Consolidated Wake Turbulence (CWT). This Order is accessible here: https://www.faa.gov/documentLibrary/media/Order/2021-11-08_JO_7110.126B_Consolidated_Wake_Turbulence__FINAL.pdf.
This order provides for more modern and less broad wake turbulence separation standards. Under the old wake turbulence system, a B744 and a A306 were both "Heavy". This means they required 4nm of wake turbulence separation between them. However, the B744 has a maximum takeoff weight that is more than twice that of the A306. The FAA determined that the B744 is an "upper heavy" and the A306 is a "lower heavy".
A full list of aircraft types and their CWT categories can be found in FAA JO 7360.1, but a list of common types and categories is pictured below:
So what does this change for us? No longer can we just apply 3, 4, or 5 miles between successive aircraft and hope for the best. In some situations we may need to ensure at least 8nm of separation between aircraft. However, it also means that where there is no wake turbulence separation required, we can use tower applied visual separation between successive departures assuming another form of separation will exist, including waivers. More information on CWT, including how it looks on the scope, is available in the following presentation. This presentation also references ATPA cones, which at the time of writing are only live in the D10 TRACON.