Enroute Clearance

The enroute clearance, often also called IFR clearance, is usually the first clearance that an air traffic controller gives to any departing IFR pilot. As the name suggests, it contains important instructions for the flight route the pilot is cleared for.

Fortunately, the structure of an enroute clearance is always the same. It consists of the following elements:

Clearance Limit
Departure route
Clearance of the route
Initial Climb
Transponder code

These elements will be explained in more detail below, followed by phraseological examples at the end.

Clearance Limit

The so-called clearance limit indicates the waypoint / airport up to which the enroute clearance is valid.

At this point, we briefly need to talk about different flight plans. While IFR and VFR are commonly known, the two more exotic flight plan types Y and Z are mostly unknown.

Flugpläne

I	IFR flight plan	The entire flight is conducted according to instrument flight rules. Example: EDDM to EDDN - Route: AKINI Delivery must issue an enroute clearance.
V	VFR flight plan	The entire flight is conducted according to visual flight rules. Delivery is only responsible for the VFR startup clearance if necessary (regulated in the SOP of the respective airport).
Z	ZULU flight plan VFR -> IFR	Take-off with visual flight rules, IFR will be flown from a certain point enroute. Example: EDDM to EDDN - Route: WLD UPALA/N0120F070 In this example, the pilot departs VFR from Munich and wants to fly IFR from UPALA. As the flight departs VFR from Munich, Delivery treats this flight as a normal VFR departure. The fact that this flight wants to fly IFR later is not relevant.
Y	YANKEE flight plan IFR -> VFR	The flight takes off according to instrument flight rules and flies VFR from a certain point enroute. Example: EDDM to EDDN - route: INPUD Y102 UPALA VFR In this example, the pilot flies IFR from Munich via INPUD and then to UPALA on airway Y102. From UPALA, the pilot wants to fly VFR. As this flight is an IFR departure from Munich, Delivery must issue an enroute clearance.

Briefly summarized: For VFR and Z, Delivery must issue a VFR startup clearance (if necessary depending on the airport). For IFR and Y, Delivery must issue an IFR enroute clearance.

But why is all this in the Clearance Limit section?

With IFR flight plans, the pilot flies completely IFR up to the destination airport, which is why the IFR route clearance must also extend to the destination airport. The clearance limit for IFR flight plans is therefore always the destination airport.

With Y flight plans, however, the pilot only flies IFR up to a waypoint, VOR, NDB, etc. IFR. The clearance limit for Y flight plans is therefore not the destination airport, but the last waypoint before the pilot switches to VFR according to the flight plan

Phraseology

The clearance limit is expressed by the phraseology CLEARED TO (clearance limit). In our example for IFR flight plans, we would therefore say

CLEARED TO NÜRNBERG

In our example for Y flight plans (route: INPUD Y102 UPALA VFR) we would say:

CLEARED TO UPALA

Departure Route

In the second part of the IFR route clearance, the pilot is told which departure route to take off on. We deal with two different cases in the S2 training:

Standard Instrument Departure (SID)

The SID is the most common and probably best-known departure procedure for instrument flights. A valid flight plan always contains the end point of a SID as the first waypoint like for example AKANU in Nuremberg and MERSI in Munich. From this point onwards, the pilot has various airways and waypoints listed in the flight plan that will ultimately take them to the destination aerodrome. If the airways are regarded as highways, the SIDs would be the highway access points, i.e. routes from a connection point (airfield) to the highways (airways). The published SIDs depend on the airport’s operating direction and contain information on flight direction, altitude and speeds. An easy way to access the corresponding charts is offered by the provider Chartfox, where you can easily log in with your VATSIM account. Follow this link and take a look at the departure routes of runway 26R in Munich for the MIQ, GIVMI and RIDAR waypoints.

Vectored Departure

Sometimes it is not possible to assign a SID. There can be various reasons for this: Some airfields require certain aircraft equipment (e.g. GPS) for certain departure routes, sometimes the pilot has problems with their FMS and therefore cannot fly the SID. A third reason that occurs from time to time is pilots who want to fly so-called IFR patterns. These are often flown during landing training. After departure from the approach, the pilot is guided to the ILS via vectors and then handed back to the tower. After the touch and go, the pilot is handed back to APP and the game starts all over again. With such procedures, it makes no sense to release the pilot to a SID, as this is designed to bring the pilot into the airway system. With IFR patterns, however, the pilot does not want to go to an airway, but to remain at our airfield.

A vectored departure must ALWAYS be coordinated with Approach or the Center station above. If you control Delivery, the Tower also needs to be informed.

Example of coordination:

EDDN_TWR: Approach, Nürnberg Tower
EDDN_APP: Go ahead
EDDN_TWR: Request vectored departure DLH414 for IFR Pattern
EDDN_APP: Approved, on RWY Heading climb FL070

Phraseology

SID: The SID is cleared by simply stating the SID’s name and the addition ‘departure’. In the example of the GIVMI departure in Munich from runway 26R:
*VIA* GIVMI1N DEPARTURE
The word via is optional. It is not necessary to specify the runway in this case, as the SID GIVMI1N only starts from runway 26R. If the pilot knows their SID, they therefore also know their runway. However, there are also SIDs that can be flown from several runways (e.g. in Frankfurt for runway 25C/L). In this case, the runway must be defined in the enroute clearance unless the departure runway is obvious due to the ATIS
Vectored Departure: After Approach has told you how they want the departure, you must pass on the relevant information to the pilot:
*VIA* VECTORED DEPARTURE RWY 28, CLIMB ON RWY HEADING FL70

The tower controller must then also be informed of the vectored departure so that they know where the aircraft is going to fly initially.

Clearance of the route

After the first two items of the clearance, we have told the pilot up to which point their route clearance applies and how they should fly to the first waypoint in the flight plan. What is still missing, however, is how they should fly from the first waypoint or the SID endpoint to the clearance limit.

In many cases, this is supposed to happen via the route filed in the flight plan. We express this with the following speech group:

FLIGHT PLANNED ROUTE.

Initial Climb

Even if every SID has a permanently assigned initial climb in the charts or in the AIP, since 2020 this has had to be explicitly mentioned in every IFR enroute clearance. The initial climb is the altitude up to which the pilot may climb independently after take-off without further clearance.

There are, however, two different versions of this speech group:

There are SIDs that have neither altitude nor speed limits. Here we use:

CLIMB TO *ALTITUDE* 5000 FT

There are SIDs that have either altitude or speed limits or both. Here we use:

CLIMB VIA SID TO *ALTITUDE* 5000 FT

In the case of a vectored departure, this speech group is omitted, as the altitude instruction is already given when the flight route is communicated (e.g. ON RWY HEADING CLIMB TO FL70).

The word Altitude or Flight Level is optional. However, it is recommended, especially in the case of altitude, to avoid misunderstandings with the "to" ("Climb to four thousand feet" vs. "Climb two four thousand feet").

Transponder code

Last, but not least, the transponder code. The purpose of this is to uniquely identify an aircraft on radar.

The transponder code is simply added after the word SQUAWK, e.g.

SQUAWK 2001

Each digit is pronounced individually, unless the transponder code consists of full thousands. In this case, the code must be pronounced as follows: SQUAWK 1000 = SQUAWK ONE TOUSAND.

Phraseology examples

If we bring these items together we can create our first IFR enroute clearance.

As an example, let’s assume a flight from Nuremberg to Munich with the route AKANU from runway 28. The transponder code is 1000. We assume that there is little traffic and therefore also issue the startup clearance. The callsign is DLH414.

The complete transmission is:

DLH414, STARTUP APPROVED, CLEARED TO MÜNCHEN, *VIA* AKANU8K DEPARTURE, FLIGHT PLANNED ROUTE, CLIMB TO FL70, SQUAWK 1000, (additional information or instructions)

The words printed in bold are always the same, the words in normal print must be adapted to the respective flight.

The phraseology for a Vectored Departure is:

DLH414, STARTUP APPROVED, CLEARED TO MÜNCHEN, *VIA* VECTORED DEPARTURE RUNWAY 28, CLIMB ON RWY HEADING TO FL70, FLIGHT PLANNED ROUTE, SQUAWK 1000, when airborne contact München Radar 129.525.

Perhaps you are now wondering why the departure frequency is mentioned in the Vectored Departure. Well, all SIDs in Nuremberg state on the charts that the pilot should call 129.525 after take-off, so if a pilot is cleared for the AKANU8K, for example, they are also instructed to call 129.525 after take-off. For a vectored departure, however, there is no chart on which the pilot can find this information. We must therefore give them this instruction separately with the enroute clearance.