APP/ACC

Key Definitions

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 toward after leaving the current sector.

For example, if an aircraft is transitioning through sectors A → B → C, then from the perspective of sector B:

Sector A is the upstream sector.
Sector C is the downstream sector.

Coordination Point (COP)

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

In many operational setups:

COPN (Entry COP) marks the handoff point for aircraft entering the sector.
COPX (Exit COP) marks the point where an aircraft leaves the sector.

When coordinating handoffs, controllers should refer to recognizable waypoints, VORs, or major aerodromes rather than obscure landmarks that may not be known to the receiving controller. In a simulated environment like VATSIM, specifying the aircraft’s exact location can be useful since pre-planned coordination may be less structured.

Transfer of Control

The transfer of control refers to the moment when responsibility for issuing flight instructions—such as altitude changes, heading adjustments, or speed restrictions—shifts from one controller to another.

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

For example, if the required separation is 3 NM, the aircraft should maintain at least 1.5 NM from the boundary on each side. This ensures that both sectors collectively maintain the full separation requirement without requiring additional coordination.

Silent Transfer of Control

In some cases, silent transfer of control is defined within LoAs. This means that under specific conditions, an aircraft can be handed off to the receiving controller without requiring additional verbal coordination. These agreements streamline operations by allowing controllers to focus on active conflicts rather than routine handovers.

Transfer of Communication (≠ Transfer of Control)

A transfer of communication occurs when an aircraft is instructed to switch to a new ATC frequency. This does not necessarily mean that control of the flight is being transferred at the same time. Communication and control can be transferred separately based on operational requirements.

Controller Initials

In real-world air traffic control centers, each controller is identified by a unique set of initials, typically formed from the first letter of their first and last name.

During coordination calls, initials serve as a form of acknowledgment—signaling that both controllers agree on the discussed handover. The conversation is only concluded once both parties state their initials, effectively marking the coordination as finalized.

Approval Request

For coordination purposes, certain keywords provide the coordination partner with a general understanding of the situation during initial contact. One such keyword is "Approval Request." This phrase is used in the following scenarios:

Direct Request (Downstream)

For various reasons, such as a pilot's request, efficiency, or problem-solving within the sector, it is often beneficial to grant a direct route to a waypoint instead of following the filed flight plan. Within a controller's own sector, this is possible without coordination. However, if the waypoint is in an adjacent sector, approval from the next (downstream) sector is required. This can be requested either via the Euroscope coordination function or verbally.

Verbal coordination follows this structure:

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

After initiating contact, wait for the called sector's "Go ahead" before proceeding. This allows the receiving sector time to check the aircraft’s position on radar and within their sector list. Once permission is granted, the request is processed and either accepted or denied accordingly.

Climbing/Descending (Downstream)

Unless otherwise stated in a Letter of Agreement (LoA), a fundamental principle in air traffic control is that aircraft should not be climbing or descending at a sector boundary. Lateral entry and exit require aircraft to be "at level." Any vertical movement during sector crossing (including half the minimum separation distance before the boundary) must be coordinated. Since this coordination cannot be handled through Euroscope, verbal coordination is always required.

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

Deviation from Coordinated Level

If an aircraft needs to be handed off at a level different from what was agreed upon in the LoA, coordination is required. This can be done using Euroscope functions or verbally.

Clearing Through Third-Party Sectors

When an aircraft needs clearance through an uninvolved sector, coordination is necessary. In such cases, a standard COP (Coordination Point) is not applicable because the aircraft would not normally pass through this sector. The affected sector lacks flight details in Euroscope and does not classify the aircraft as concerned, meaning standard coordination procedures do not apply.

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, 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 replaces the originally intended downstream sector after coordination, an additional request format can be used:

APPROVAL REQUEST FOR ADDITIONAL TRAFFIC AIRBORNE KÖLN <call sign>
DCT KRH FL250

This implies that further downstream coordination is now the responsibility of the accepting sector.

Less Spacing Than Agreed Upon

In Maghreb LoAs, silent transfer of control typically requires a spacing of 10 miles at the same speed. The following rules apply for silent transfer of control at the same flight level:

If the leading aircraft is at the same speed or faster: 10nm

If 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, none of the above conditions are met. In this case, either speed control must be applied to ensure they are at the same speed or coordination is required.

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

Release

As previously defined, the TRANSFER OF CONTROL occurs when an aircraft crosses the sector boundary plus half the radar separation value, unless otherwise specified. If the receiving sector wishes to issue instructions altering the flight trajectory before the actual TRANSFER OF CONTROL, they must request a RELEASE.

A release is permission granted by the transferring sector to the receiving sector for the premature assumption of control of a flight.

Types of Release

Release for (Right/Left) Turn

Allows the receiving sector to turn the aircraft up to 45 degrees before the actual transfer of control. The release can be restricted to either left or right turns.

Release for Climb

Allows the receiving sector to instruct a climb or adjust the rate of climb prior to the actual transfer of control.

Release for Descent

Allows the receiving sector to instruct a descent or modify the descent rate before the actual transfer of control.

(Full) Release

A general release includes turn, climb, and descent release, granting full control to the receiving sector.

Requesting a Release

A release can be sent directly with the transfer via Euroscope using the TopSky plug-in. If this has not been done and the receiving sector wishes to control the flight before the TRANSFER OF CONTROL, the release must be obtained verbally. The following phraseology is used:

REQUEST RELEASE <callsign>

Example:

EDMM
REQUEST RELEASE (FOR (RIGHT/LEFT) TURNS / FOR CLIMB / FOR DESCENT) DLH123

EDGG
DLH123 RELEASED (FOR (RIGHT/LEFT) TURNS / FOR CLIMB / FOR DESCENT) <initials>

EDMM
<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, a Release Subject Your Discretion (SYD) can be issued. This means the aircraft is released, but the receiving sector must ensure separation from specified traffic.

Example of SYD Release:

EDMM
REQUEST RELEASE DLH123

EDGG
DLH123 RELEASED SYD RYR123 overhead Dinkelsbühl on N869, FL200 <initials>

EDMM
<initials>

In this case, Munich (EDMM) wants to allow DLH123 to descend, but Langen (EDGG) has crossing traffic at FL200 on N869. With this release, Munich can initially descend DLH123 to FL210 and then, once lateral separation is ensured, allow further descent.

The key factor in a SYD release is that both coordination partners understand who is responsible for separation after coordination. Additionally, the receiving sector must be fully aware of the location and status of the restricting traffic to maintain safe operations.

Reference

Anything that cannot be handled through an Approval Request or a Release falls under the coordination type Reference.

Primary Use Case

The most common application of a reference is a request to the upstream sector. Whenever an aircraft needs to enter a sector in a manner that deviates from the standard, a reference call is made.

EDMM
REFERENCE DKB DLH123
REFERENCE 20 MILES WEST OF DKB DLH123

EDGG
Go ahead

EDMM
REQUEST HIM DIRECT LANDU
REQUEST HIM DCT DM424, DESCENDING FL150
REQUEST HIM AT FL210
REQUEST HIM AT SPEED 250 KNOTS

EDGG
CONSIDER <initials>
WILCO <initials>
UNABLE <initials>

EDMM
<initials>

The responses CONSIDER and WILCO both mean that the request is accepted by the upstream sector. Since the receiving unit determines the conditions for entry, a request should only be rejected or renegotiated in 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 for Requests

In certain cases, the sending sector may also make a request using a Reference Call instead of an Approval Request. This allows for an open-ended request rather than a predefined coordination action.

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

This is particularly useful for transitions between:

Approach (APP) and Center (CTR)

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

Such calls are beneficial when a departing or arriving aircraft needs to reach its assigned exit level before a handoff can occur. If a crossing has not yet been completed, coordinating for a higher/lower level allows for continuous climb, descent, or flexible problem-solving.

Departure Release

At certain airports, a Departure Release must be obtained from the radar sector before each IFR departure. This is because the radar sector is responsible for ensuring separation between IFR arrivals and departures. Whether a departure release is required is specified in the airport’s Tower SOP.

Coordination Process

If a release is required, coordination follows this structure:

EDFH TWR
REQUEST RELEASE DLH123

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

EDFH TWR
<initials>

Types of Responses

A departure release can be:

Approved without restriction → Immediate release granted.

Approved with restriction → The release is conditional (e.g., after an arrival has landed or before a certain time limit).

Denied → The departure is not currently possible, and the radar controller will call back when feasible.

Understanding these responses ensures smooth coordination and efficient traffic management.

Handover Tower

A proper handover is an essential part of a controller’s workflow and has become increasingly relevant on VATSIM, especially during long events such as Munich 11 to 11, Berlin Overload, or Frankfurt RFO.

This guide outlines the key steps for conducting a structured and efficient handover in the tower environment.

General Considerations

When a handover is imminent (e.g., when the incoming controller joins TeamSpeak), it is advisable to simplify traffic as much as possible. Specifically:

Handle standard traffic only.

Avoid complex situations or unresolved conflicts.

Complete coordination with neighboring stations to ensure a clear traffic picture at handover.

Transfer unnecessary aircraft to the next controller beforehand.

To ensure a quick and effective handover, the outgoing controller should plan in advance what needs to be communicated. This is particularly critical during high-traffic periods, as handover errors in such situations can be more consequential.

Both controllers should confirm readiness before starting the handover. The handover completion should be explicitly stated to avoid confusion about who is responsible for the position. The outgoing controller should remain available for a few minutes after handover to address any immediate issues.

WEST Principle for Tower Handover

A structured handover in the tower environment follows the WEST principle:

Category	Explanation	Examples
W - Weather	Weather significantly impacts operations and must always be communicated.	- "CTR VMC / CTR IMC"

"Runway direction 25"

"West wind, medium strength"

"Thunderstorm west of the field"

"A320 reported wind shear, 2 NM final, lost 30 kt IAS, 200 ft altitude loss" | | E - Equipment | Any equipment issues affecting operations should be noted. On VATSIM, this is rarely relevant. | - "Audio for VATSIM connection issues reported by multiple controllers" | | S - Situation | Describe the current operational environment, including online stations, closures, special events, and agreements. | - "Ground, Approach, and Feeder online"

"Taxiway Whiskey closed"

"Shuttle event between Frankfurt and London"

"Minimum inbound spacing coordinated with Approach"

"Departure frequency for all southern departures is 119.2" | | T - Traffic | Outline relevant aircraft within or about to enter the airspace. | - "DISTM filed a Y flight plan, clearance limit CHA, not yet called in"

"DLH4FM has IFR clearance but no startup"

"BER224 at position 116, long pushback, blue line, nose south"

"CXI2247 rolling for takeoff"

"RYR2NT at 8 NM, speed 160 kt until 4 NM, no landing clearance"

"DEMIL, VFR inbound via Echo, cleared into CTR and circuit" |

The WEST principle serves as a guideline for a clean handover. Any additional important information that does not fit into these categories should still be communicated.

However, irrelevant information should be omitted. For example, during clear weather, there is no need to mention that "there is no thunderstorm."

Example Handover

Control zone VMC,
Runway direction 25,
Clear west wind, medium speed.

We have online: Ground, Approach, and Feeder.
Taxiway Whiskey closed.
No gaps requested by Feeder.

Traffic overview:
- SAS842, just departed from RWY 25.
- DLA9H, at holding point RWY 25, awaiting takeoff clearance.
- PBW11, helicopter VFR, at southern helipad, requesting departure via Echo.
- BAW917S, at 6NM, on frequency, no landing clearance.

Any questions?

A well-structured handover ensures smooth transitions between controllers, reducing errors and maintaining operational efficiency.

Handover Approach / Feeder / Center

While the "Handover Tower" article introduced the WEST principle, this guide presents a more practical approach for handovers between Approach and Center. The WEST principle can still be used in parallel, but it does not comprehensively cover all relevant aspects of such handovers.

For a structured handover between Approach and Center, it is best to move from general to specific:

Basic information – Own area of responsibility and runway direction(s).

Sector configuration & agreements – Adjacent sectors and agreements.

Traffic details – Aircraft on frequency and coordination status.

Additional information – Any other relevant notes.

This approach helps the incoming controller gradually build an understanding of the traffic picture. There is no strict phraseology for handovers—the key is mutual understanding. If anything is unclear, ask.

The handover controller remains responsible for the frequency during the entire handover. In high-traffic situations, a handover can take several minutes. The relieving controller should take over with a clear "my frequency" only when they fully understand the situation.

Handover Breakdown

Basic Information & Weather

Own area of responsibility, active runways, approach configuration, special meteorological conditions, and important NOTAMs.

Example (Approach)

"You are Frankfurt Pickup-North; Feeder and Pickup-South are online. 25 and 18 active, 25R has 2.5 NM minimum spacing for Y approaches, 25L has 6 NM spacing due to departures. Strong west wind—fast downwind, turbulence reported."

Example (Center)

"You are the DKB sector without upper. Frankfurt 25, Stuttgart 25, Mannheim 27, Baden-Baden 21. All runways west except Baden (03)."

Sector Configuration & Agreements

Which adjacent sectors are online and any special agreements. Go through them in a logical order to avoid forgetting anything.

Example (Approach)

"DKB is online, we have direct NOMBO for CINDY departures, direct ARPEG for Amsterdam. GIN, DKB, and RUD are online."

Example (Center)

"ZUG is online and covering ALB. Frankfurt inbounds come in descending; we may send Munich inbounds direct to ROKIL. HOF and GIN are online. Zurich needs 20 NM spacing for LSZH inbounds."

Traffic

Who is on frequency?

What is the plan for the aircraft on frequency?

Who else is calling, and what has already been coordinated?

Example (Approach)

"ITY414 handed off. DLH123 is first in sequence, at 5000 ft. DLH45H descending to FL70, needs speed reduction soon. DLH401 is inbound for 25S, DLH12J just checked in at RAMOB."

Example (Center)

"SWR2FR descending FL220. Once clear of BCS34T, he can be transferred. DLH123 still at Munich but has a direct SPESA entered."

Additional Information

Any remaining relevant details.

Example (Approach)

"We had multiple voice server issues earlier."

Example (Center)

"Parachute dropper at NETEX has called in several times; expect them again soon."

Example Handovers

Approach Handover Example

You take over Frankfurt Pickup-North, Pickup-South and both feeders are online.

We have runways 25 and 18, independent parallel approaches. Y approaches on 25R, 2.5 NM minimum spacing.

Winds are strong westerly, fast downwind, turbulence reported.

GIN, DKB, and RUD are online. We are allowed direct NOMBO for CINDY departures and direct ARPEG for Amsterdam departures.

ITY414 already handed off. DLH123 is first in sequence at 5000 ft, followed by DLH45H descending to FL70, needs speed reduction soon. DLH401 inbound for 25S, DLH12J just called at RAMOB.

Any questions?

Center Handover Example

You take over DKB. SLN is online. Stuttgart is only staffed with Tower.

All runways are west direction except Baden (03).

GIN, FUL, and Zurich are online, no special agreements.

Only SWR2FR is descending FL220 on the frequency. Once clear of BCS34T, he can be transferred.

I have entered direct SPESA for DLH123, but he is still in Munich airspace.

Any questions?

Feeder Handovers

For Feeder handovers, key weather conditions are emphasized more, as wind directly impacts spacing and sequencing. However, sector configuration details are less relevant, since a Feeder sector is never active without a Pickup sector.

Example Feeder Handover

Runways 25, you are Feeder for both runways. Dependent parallel approaches, Y approaches on 25R.

General spacing: 5 NM due to departures on both runways.

Strong winds, aircraft are reducing speed quickly.

ITY414 has 180 kt until 6NM, already with Tower.

SWR2FR behind it needs to slow down soon.

DLH404 is on base turn for 25L.

AUA1LN will call next.

Any questions?