APP/ACC

Throughout the following sections, several important terms will be used. Below are their definitions to ensure clarity.

Upstream and Downstream Sectors

• Upstream Sector: The airspace sector an aircraft is coming from before entering the current sector.
• Downstream Sector: The airspace sector an aircraft is heading towardto after leaving the current sector.

For example, ifExample
If an aircraft is transitioningtransitions through sectorsSector A → B → C, then from the perspective of sector B:C:

• From Sector B’s perspective:
  • Sector A is the upstream sector (where the aircraft is coming from).
  • Sector C is the downstream sector (where the aircraft is going).

Coordination Point (COP)

A Coordination Point (COP) is typically a designated waypoint close tonear a sector boundary where aircraft are handed off between controllers. This reference point helps both the transferring and receiving controllers manage traffic more efficiently.

InCommon manyCOP operational setups:types:

• COPN (Entry COP) marks– the handoffThe point forwhere an aircraft enteringenters the sector.
• COPX (Exit COP) marks– theThe point where an aircraft leaves the sector.

When coordinating handoffs, controllersControllers should referuse to recognizablewell-known waypoints, VORs, or major aerodromes ratherwhen thancoordinating obscure landmarks that may not be known to the receiving controller.handoffs. In a simulated environment like VATSIM, specifying the aircraft’s exact location canof bean aircraft is useful since pre-planned coordination may beis less structured.structured than in real-world operations.

Transfer of Control

The transfer of control refers to the momentoccurs when responsibility for issuing flight instructions—suchinstructions as(altitude, altitudeheading, changes,speed) heading adjustments, or speed restrictions—shiftsmoves from one controller to another.

Unless otherwise specified in verbal agreements or a Letter of Agreement (LoA), or verbal coordination, control is transferred oncewhen the aircraft enters the new sector and has reached at least half of the required minimum separation distance from the sector boundary.

ForExample

example,

if
• If the required separation is 3 NM, control is considered transferred once the aircraft should maintain at leastis 1.5 NM frominto the boundaryreceiving onsector.
each

side.

This ensures that both sectors collectively maintain the full separation requirement without requiring additional coordination.

Silent Transfer of Control

In some cases, an LoA allows for silent transfer of control, is defined within LoAs. This means that under specific conditions,meaning an aircraft can be handed off to the receiving controller without requiring additional verbal coordination.

These

This agreementsapplies streamlinewhen:

operations

by
• The allowingaircraft controllersmeets pre-agreed conditions.
• The receiving controller is already aware of the aircraft.
• The route, level, and conditions do not require coordination.

Certain routes, levels, and airspace have predefined silent coordination agreements, eliminating the need for verbal coordination. However, restrictions may still apply, preventing changes close to focussector onboundaries.

active

Handoffs

conflicts

A ratherhandoff occurs when control of an aircraft is transferred between controllers.

Once a receiving controller accepts a handoff, they can:

• Turn the aircraft up to 45 degrees left or right without further coordination.
• Climb or descend the aircraft to any level without additional coordination.

Handoff Restrictions

• Do not hand off an aircraft if a turn of more than routine45 handovers.
  degrees or a level change will cause a conflict.
• If needed, apply restrictions before the handoff to ensure separation.

Full Control After Handoff

• Once the aircraft is within half the applicable lateral standard (2.5 NM for ENR, 1.5 NM for TWR/APP), the receiving controller can issue unrestricted turns and level changes.
• If a turn greater than 45 degrees is needed earlier, coordination is required.

Transfer of Communication

A transfer of communication occurshappens when an aircraft is instructed to switch to a new ATC frequency.

• This does not necessarilyalways mean that control ofhas thebeen flighttransferred.
is being transferred at the same time.
• Communication and control transfers can be transferredhappen separately based on operational requirements.needs.

For example, a controller may hand off communication early while still retaining control of the aircraft for sequencing or separation purposes.

Controller Initials in Coordination

In real-world airATC, trafficcontrollers control centers, each controller isare identified by a unique set of initials, typically (formed from the first letter of their first and last name.names).

During verbal coordination calls,, initials serveare exchanged as a form of acknowledgment—signalingconfirmation that both controllers agree on the discussedhandover.

handover.

• The conversation is onlynot concludedcomplete onceuntil both partiescontrollers state their initials,initials.
effectively

marking

Approval the coordination as finalized.

Request

When a controller needs approval from another sector for a specific action, an Approval Request is used.

ForThis coordinationis purposes,common certainfor:

keywords

provide
1. Direct theRouting coordinationRequests
partner
2. Climbing withor Descending Across a generalSector understandingBoundary
3. Deviations from Agreed Flight Levels

Each type of therequest situationfollows duringa initialstandard contact.format Oneto suchensure keywordclarity isand "Approval Request." This phrase is usedefficiency in the following scenarios:coordination.

Direct Routing Request (Downstream)

Downstream Coordination)

For various reasons, such asGranting a pilot'sdirect-to request,waypoint clearance can improve efficiency, accommodate pilot requests, or problem-solvingresolve within the sector, it is often beneficial to grant a direct route to a waypoint instead of following the filed flight plan.conflicts. Within a controller's own sector,sector, this iscan possiblebe done without coordination. However, if the waypoint is in an adjacent sector,sector, approval from the nextdownstream (downstream) sectorcontroller is required.

This request can be requestedmade eitherusing via the Euroscope coordination functionfunctions or verbally.verbally.

Format for Verbal coordination follows this structure:

Coordination

APPROVAL REQUEST <COP/position> <call sign>
DCT <WPTwaypoint>

After

Procedure

initiating

contact,
1. Contact the receiving sector and wait for thetheir called sector's "Go ahead" beforeresponse.
proceeding.
2. This allows the receiving sector timecontroller to check the aircraft’s position on radar and withinpotential theirconflicts.
sector list.
3. Once permission is granted, the request is processed and either acceptedapproved or denied.
accordingly.

Climbing/Descending (Downstream)

at Sector Boundaries

UnlessBy otherwise stated in a Letter of Agreement (LoA), a fundamental principle in air traffic control is thatdefault, aircraft should not be climbinglevel orwhen descending atcrossing a sector boundary.boundary Lateralunless entryan andLoA exit(Letter requireof aircraftAgreement) tostates otherwise.

• Any climb or descent at or near a boundary must be "atcoordinated.
level."
• Coordination Anyis required if vertical movement duringoccurs sector crossing (includingwithin half of the minimum separation distance before the boundary)aircraft enters the next sector.
• This type of coordination must be coordinated.done Sinceverbally, thisas coordinationEuroscope cannotdoes benot handledhandle throughaltitude Euroscope,change verbalrequests coordinationautomatically.
is

always

Format required.

for Verbal Coordination

APPROVAL REQUEST <COP/position> <call sign>
CLIMBING <level>
 / DESCENDING <level>

Deviation from CoordinatedAgreed Flight Level

If an aircraft needsmust tocross bea handedsector offboundary at a different level different from what wasthan agreed upon in the LoA, coordination is required. This can be done usingusing:

• Euroscope functions
or
• Verbal verbally.
  coordination

Clearing Through a Third-Party Sectors

Sector

WhenIf an aircraft needsrequires clearance through ana uninvolvedsector sector,that is not normally involved, additional coordination is necessary.needed.

In

such
• Standard cases,Coordination a standard COPPoints (CoordinationCOPs) Point)do not apply, as the aircraft is not applicableexpected becauseto enter the aircraft would not normally pass through thisthird-party sector.
• The affected sector lacksdoes not have flight details in Euroscope and does not classifyconsider the aircraft as concerned,relevant meaningtraffic.
standard

coordination

Format proceduresfor doVerbal not apply.

Coordination

APPROVAL REQUEST FOR AIRSPACE CROSSING <call sign> <position>
CLIMB UP TO FLxxx (routing)
 / DESCEND DOWN TO FLxxx (routing)

This situation is often mistaken for a release,release, but it is strictly an approval request. Releases are discussed in a separate section.

If the previously uninvolved sector assumes full control of the aircraft or replacestakes over from the originally intendedplanned downstream sector after coordination,sector, an additional request format can beis used:

APPROVAL REQUEST FOR ADDITIONAL TRAFFIC AIRBORNE KÖLNMARRAKECH <call sign>
DCT KRHSLK FL250FL300

This impliesshifts thatthe responsibility of further downstream coordination is now the responsibility ofto the accepting sector.

Less

Boundary Coordination

Boundary coordination is required when an aircraft is expected to deviate within half of the required separation for another sector’s airspace.

This applies if an aircraft is within:

• 500 ft vertically
• 2.5 NM laterally (enroute sectors)
• 1.5 NM laterally (approach/tower sectors)

Boundary coordination informs the adjacent sector about the aircraft and allows them to impose restrictions if necessary.

Format for Verbal Coordination

• Controlling Sector → Boundary Sector:

For Ident, (Position), (Callsign), (Details as required)

• Boundary Sector → Controlling Sector:

(Callsign), (Restriction)

Example Phraseology

SOU → NOR: "For Ident, overhead SAK, RAM12, do you have any restrictions on descent?"
NOR → SOU: "RAM12, No restrictions on descent."

If the boundary sector has no restrictions, they may omit the restriction and simply read back the callsign. This confirms that no vertical or lateral restrictions apply.

Example Phraseology with Omission

WES → EAS: "For Ident, west of RAVMA, AB123"
EAS → WES: "AB123"

Spacing ThanBelow AgreedStandard Upon

Separation

In Maghreb LoAs,LoAs, silent transfer of control typically requires a spacing of 10 milesNM separation at the same speed.speed. The following rules apply forwhen silenttransferring transfer of controlaircraft at the same flight level:level:

If

theleading

Condition	Required Separation
Leading aircraft is at the same speed or faster:faster	10 NM
Trailing aircraft is 10nmup to 20 knots / M0.05 faster	20 NM
Trailing aircraft is up to 40 knots / M0.10 faster	30 NM

Example Scenario

IfTwo aircraft are transferred with 15 NM separation, but the trailing aircraft is up to 20 knots/M0.05 faster: 20nm

• If the trailing aircraft is up to 40 knots/M0.10 faster: 30nm

For instance, if two aircraft are to be transferred with a 15-mile separation and the trailing aircraft is 30 knots faster,faster.

• Since none of the above conditions are met.met, Ineither: this
  case, either speed
  • Speed control must be applied to ensurematch they are at the same speedspeeds, or
  coordination
  • Coordination is required.
    required before transfer.

Format for Coordination

APPROVAL REQUEST <COP/position> <call sign>
<distance> <speed difference>

Release Coordination

AsA previouslyrelease defined,allows the receiving sector to issue instructions TRANSFER OF CONTROLbefore occurs when an aircraft crosses the sector boundary plusand halfcontrol theis radarofficially separationtransferred.

value,

unless otherwise specified.
• If the receiving sectorcontroller wisheswants to issue instructionsa alteringturn, theclimb, flightor trajectorydescent before the actual TRANSFER OF CONTROLtransfer, they must request a RELEASErelease.

A

• Without a release, the aircraft releasemust continue as planned until control is permissionformally grantedtransferred.
by

the transferring sector to the receiving sector for the premature assumption of control of a flight.

Types of Release

Release for (Right/Left) TurnReleases

Requesting a Release

A release can be sent directly with the transferhandoff via Euroscope using the (TopSky plug-in.in), Ifbut if this hasis not been done and, the receiving sector wishesmust to control the flight before the TRANSFER OF CONTROL,request the release mustverbally.

be

Format obtainedfor verbally.Verbal The following phraseology is used:

Request

REQUEST RELEASE <callsign>

Example Phraseology

Example:NOR → SOU:

EDMM
"REQUEST RELEASE (FOR (RIGHT/LEFT) TURNS / FOR CLIMB / FOR DESCENT) DLH123RAM123"

EDGG
DLH123SOU → NOR:

"RAM123 RELEASED (FOR (RIGHT/LEFT) TURNS / FOR CLIMB / FOR DESCENT) <initials>"

EDMM
NOR → SOU:

"<initials>"

A Coordination Point (COP) is not required in this communication.

Release Subject to Discretion (SYD)

In cases where the releasing sector has one or more aircraft that may impact the release, aA Release Subject Your Discretion (SYD) canis beused issued. This meanswhen the releasing sector has other aircraft that may impact the release.

• The aircraft is released,released, but the receiving sector mustis ensureresponsible for ensuring separation from specified traffic.

• The releasing sector provides traffic details, and the receiving controller must maintain separation accordingly.

Example of SYD Release:Release

NOR → SOU:

EDMM
"REQUEST RELEASE DLH123RAM123"

EDGG
SOU → NOR:

"DLH123 RELEASED SYD RYR123 overhead DinkelsbühlFOBAC on N869,R722, FL200FL290 <initials>

EDMM
<initials>"

InNOR this→ case,SOU:

Munich

(EDMM)

"<initials>"

Explanation

• NOR wants to allowclimb DLH123RAM123 to descend,, but Langen (EDGG)SOU has RYR123 crossing traffic at FL200FL290 on N869R722.
• With this release,SYD Munichrelease, NOR can initially descendclimb DLH123RAM123 to FL210FL280.
and then, once
• Once lateral separation is ensured, NOR can allow further descent.
  climb.

The key factor in ato SYD releasereleases is thatensuring both coordinationcontrollers partnersclearly understand who is responsible for separation.

after

Heads-Up coordination.Coordination

Additionally,

Heads-up coordination is used to notify the next sector about an incoming aircraft.

Format for Verbal Coordination

• Controlling Sector → Receiving Sector:

  "(Position), (Callsign)"

• Receiving Sector → Controlling Sector:

  "(Callsign), (Level)"

Example Phraseology

NOR → SOU:

"Via SLK, RAM1234"

SOU → NOR:

"RAM1234, F350"

If the assigned level at transfer of jurisdiction is different from the current CFL, the controlling sector must specify:

"Will be assigned (level)."

If the receiving sector needs a different level, they will respond with the amendment.

Example Phraseology with Level Change

NOR → SOU:

"Via SLK, RAM1234"

SOU → NOR:

"RAM1234, F300 due traffic"

NOR → SOU:

"F300, RAM1234"

Once coordination is completed, the aircraft’s level and route are locked in.
Any further changes must be fullyre-coordinated.

aware

Best ofPractice

• The best time to conduct Heads-Up Coordination is when the locationaircraft andfirst statuschecks ofin.
• Do not delay coordination until just before the restrictingtransfer.
traffic to maintain safe operations.

Reference Calls

Anything that cannot be handled throughWhen an action does not fit an Approval Request or Release, a ReleaseReference Call fallsis under the coordination type Reference.used.

Primary Use Case

The

most
• A common application of a reference is a request to the upstream sector.sector Wheneverwhen an aircraft needs to enter a sector in a non-standard manner.
that

deviates

Example fromReference theCall

standard,

SOU a→ reference callNOR: is made.

EDMM
"REFERENCE DKBSLK DLH123RAM123"
"REFERENCE 20 MILES WEST OF DKBSLK DLH123RAM123"

EDGG
NOR → SOU:

"Go aheadahead"

EDMM
SOU → NOR:

"REQUEST HIM DIRECT LANDUMABAP"
"REQUEST HIM DCT DM424,MAK, DESCENDING FL150FL90"
"REQUEST HIM AT FL210FL200"
"REQUEST HIM AT SPEED 250 KNOTSKNOTS"

EDGG
NOR → SOU:

"CONSIDER <initials>"
"WILCO <initials>"
"UNABLE <initials>

EDMM
<initials>"

TheSOU responses→ CONSIDERNOR:

and

"<initials>"

Reference Call Responses

• WILCO both= meanRequest thataccepted.
the
• UNABLE request= isRequest accepted by the upstream sector. Since the receiving unit determines the conditions for entry, a request should only be rejecteddenied or renegotiatedrenegotiation inneeded.
exceptional cases. Common sense should be applied to reach a mutually beneficial solution.

A note on CONSIDER: Though it may seem ambiguous at first, in German ATC communication, "CONSIDER" is often used instead of "WILCO." It does not mean that the request is being considered but rather stands for "CONSIDER IT DONE."

Using Reference Calls for Requests

In certain cases, the sending sector may also make a request using aA Reference Call can also be used instead of an Approval Request. This allows for an open-ended requestcoordination.

rather

Format thanfor aVerbal predefined coordination action.

Coordination

REFERENCE <COP/position> <callsign>
REQUEST HIGHER/LOWER LEVEL

This

Common is particularly useful for transitions between:

Uses

• Transitioning

  between Approach (APP) and Center (CTR)

• Moving

  between Lower Center (Lower CTR) and Upper Center (Upper CTR) (or vice versa)

• Ensuring climb/descent clearance before handoff

SuchIf calls are beneficial when a departing or arrivingan aircraft needs to reach its assigned exit level before a handoff can occur. If a crossing has not yet beencompleted completed,a coordinating forcrossing, a Reference Call allows controllers to coordinate a higher/lower level allows for continuoussmoother climb, descent, or flexible problem-solving.sequencing.

Departure Release

 Requirements

At certain airports, a Departure Release must be obtained from the radar sector before each IFR departure.

This

is
• The because the radar sector is(APP/ACC) responsibleensures for ensuring separation between IFR arrivals and departures.departures.
• Whether a departure requires a release is requireddetermined is specified inby the airport’s Tower SOP.

Departure Release Coordination Process

If a release is required, coordination follows this structure:

Format for Verbal Coordination

TWR → Radar (APP/ACC):

EDFH TWR
"REQUEST RELEASE DLH123DLH123"

EDGG
DLH123Radar (APP/ACC) → TWR:

"RAM123 RELEASED <initials>"
DLH123"RAM123 RELEASED AFTER LANDING RYR123 <initials>"
DLH123"RAM123 RELEASED, CLEARANCE EXPIRES AT 1530 <initials>"
DLH123"RAM123 RELEASED AT 1520 <initials>"
"UNABLE, CALL YOU BACK <initials>"

TWR → Radar (APP/ACC):

"<initials>"

If a release is denied, the radar controller will call back when the departure is approved.

Next Coordination

Departure release coordination is conducted between TWR and APP/ACC controllers to determine the next aircraft to depart.

• All IFR departures require Next Coordination unless the airport has Auto Release in place.
• Auto Release can be canceled at any time by mutual agreement between TWR and APP controllers.

Format for Verbal Coordination

TWR → APP:

"Next, (Callsign), (Runway)"

APP → TWR:

"(Callsign), (Runway), (Lateral and/or Vertical Instructions)"

Departure Instructions

Instruction	Meaning
Left/Right Turn	Make a visual left/right turn to establish on the planned outbound track.
Left 180	At the SID turn height (or safe altitude for visual departures), fly heading 180.
Left 180 Visual	Same as above, but the pilot must maintain visual separation from terrain.
Extended Runway Centerline	Track the extended runway centerline (accounting for drift).

• An amended level may be assigned.
• The term "unrestricted" may be used to indicate no vertical restrictions apply.

Note: "Unrestricted" is not a readback item.

Example Phraseology

Visual Departure Example (LAM departing from GMAD)

EDFHTWR TWR
<initials>→ APP:

"Next, LAM, runway 27"

APP → TWR:

"LAM, runway 27, left turn, unrestricted"

TWR → APP:

"Left turn, LAM"

Procedural SID Example (EZY342 from GMAD, Auto Release cancelled)

TWR → APP:

"Next, EZY342, runway 27"

APP → TWR:

"EZY342, unrestricted"

Airways Clearance Coordination

At some aerodromes, TWR must coordinate with APP/ACC before issuing an airways clearance for certain aircraft.

• This allows the APP/ACC controller to evaluate current and projected traffic levels, position staffing, and overall airspace workload before approving clearance.
• Coordination ensures seamless integration of departing aircraft into enroute traffic.

Format for Verbal Coordination

TWR → ACC:

"(Callsign) requests clearance to (Destination), (Any Other Relevant Details)"

ACC→ TWR:

"(Callsign), clearance approved"

Example Phraseology

TWR → ACC:

"AB213 requests clearance to Fez"

ACC → TWR:

"AB213, clearance approved"

If a level change or route adjustment is required, APP/ACC will provide the update during the exchange.

Important Considerations

• This coordination is a negotiation—you can reject or renegotiate clearance requests based on airspace conditions.
• If a restriction is needed, it is best to take the aircraft on frequency before issuing clearance.

Types of Departure Clearance Responses

A

departurereleasecanbe:

→

→ The releaselimit).

→

Response Type	Meaning
Approved withoutWithout restrictionRestriction	Immediate releaseclearance is granted.
Approved withWith restrictionRestriction	Clearance is conditional (e.g., after an arrival has landedlands or before a certainset timetime).
Denied	The departure is not currentlypossible possible, andat the radarmoment; controllerAPP/ACC will call back when feasible. clearance is available.

UnderstandingClear understanding of these responses ensures smooth coordination and efficient traffic management.flow.

AddendumEstimate Coordination (Not Relevant for VATSIM)

In additionreal-world ATC, an Estimate Call is used to Approvalexchange Request,an Release, and Reference, there are other types of coordination that, for various reasons, are not commonly used on VATSIM. However, they are briefly presented here for reference.aircraft’s:

Estimate

An

• Squawk
• estimateHandover calllevel
involves
• Estimated exchanging the squawk, handover level, and entry time betweeninto sectors.the Innext real-worldsector
operations,

most

Most estimates are handledautomatically automaticallyexchanged through flight data systems.systems, However,but in casescase of system failures or special circumstances,circumstances, verbal coordination is required.

For

Example example,Scenario: consider a flight from FrankfurtCasablanca (EDDF)GMMN) to MunichParis (EDDM)LFPG)

where

If the automaticautomated system is unavailable,unavailable, requiringcontrollers must verbally coordinate all estimates.

to

be
1. Tower coordinated verbally. Once the aircraft departs, the tower calls Departure to reportreports the departure time.time Theto departureAPP.
controller and subsequent controllers along the flight path have the flight plan data but lack precise times. The departure controller then
2. APP calculates the estimated time at the COP (Coordination Point) between DepartureAPP and ACC.
3. CenterAPP transmits the estimate to ACC.
and

relays

Format thisfor estimate:Verbal Coordination

APP → ACC:

DFDS
"ESTIMATE CINDYTOLSI DLH123

KNG
A320 to EDDM

DFDS
SQUAWKING 1000, ESTIMATED CINDY 1023 CLIMBING FL130 <initials>

KNG
<initials>AFR123"

MatchingACC → APP:

"A320 to LFPG"

APP → ACC:

"SQUAWKING 6032, ESTIMATED TOLSI 1509, CLIMBING FL150 <initials>"

ACC → APP:

"<initials>"

By confirming the aircraft type and destination ensures that, both controllers ensure they are referencing the same flight. The receiving Center controller then calculates the time and level at the next COP and relays this information accordingly.

On VATSIM, estimates are not necessary because exact times are not as critical, and data exchange via Euroscope is always available.

Estimate - No Details

AnA variation of an Estimate - No DetailsCall is a variation used when the receiving sector has no prior flight plan data for an aircraft.

• This is often requiredcommon in bad weather scenariosdiversions whenor aunexpected reroutes.
• Additional flight deviatesdetails intomust abe sector not originally included in its planned route. In additionexchanged to squawk,fill time,in andmissing levelinformation,.
the

following

Additional detailsDetails are exchanged:

Exchanged

• Aircraft type

• Speed

• Requested level

• Departure airport

• Destination airport

• Route

Estimates are not required on VATSIM, as Euroscope automatically exchanges flight data

Expedite Clearance & Revisions

Expedite Clearance

An Expedite Clearance is essentially a short-term estimatecoordination andrequest, functions similarlysimilar to an Approval Request.

When

• Used when an aircraft is expectedapproaching toa reach the sector boundary in less timefaster than specifiedexpected.
in agreements, an
• Expedite Clearance must be coordinated instead ofReplaces a standard Estimate.
   when coordination time is limited.

When to Use an Expedite Clearance

• The aircraft is reaching the sector boundary sooner than specified in agreements.
• The receiving sector needs to be informed immediately to adjust sequencing or separation.

RevisionRevisions

A Revision is issued when there is ana early change in the aircraft’s estimated time,boundary flight level, or othercrossing parameters before reaching the sector boundary.

Common Revisions

• Updated estimated crossing time
• Change in flight level
• Routing adjustments

On VATSIM, revisionsRevisions are generally notunnecessary requiredon VATSIM, as Euroscope automatically updates areestimates.
Controllers automaticallycan reflectedmonitor changes in Euroscopereal-time. without requiring verbal coordination.