The indications presented on the ATS surveillance system named radar may
be used to perform the aerodrome, approach and en-route control
At IVAO, the ATS surveillance system is the IVAO ATC software which
simulates a secondary radar.
In this document, all items referred to as "ATS surveillance systems" in
official regulations documentation is translated by the generic word
"radar" as IVAO only provides a secondary radar system.
Direct pilot controller communications shall be established prior to the
provision of radar services.
The number of aircraft simultaneously provided with ATS surveillance
services shall not exceed that which can safely be handled
The radar system can be used in order to help ATC to perform its tasks.
The information provided by the radar and presented on a situation
display may be used to perform the function of air traffic control
In real life, an ATS surveillance system provides:
In IVAO ATC software radar software, today, it is not possible to handle
minimum safe altitude warning and extended conflict prediction like in
the real ATS surveillance systems.
Identification of aircraft consists of:
At IVAO, the radar label is automatically displayed on the IVAO ATC
software radar screen if the transponder code is compatible with a
controlled code. The figure shows an identified aircraft plot.
When the radar is not
displaying an aircraft label, in order to identify an aircraft, ATC can:
The separation between aircraft is possible when radar provides:
An aircraft shall be informed of its position under radar surveillance
service in the following circumstances:
Position information can be one of the following possibilities:
The vertical separation minimum (VSM) is 300m (1000ft) below FL290 and
600m (2000ft) above FL290.
For the airspace where the reduced vertical separation minimum (RVSM) is
applicable, the separation minimum is 300m (1000ft) below FL410 and 600m
(2000ft) above FL410.
The horizontal separation minimum based on radar and/or ADS-B shall be
In some cases, the horizontal separation may be reduced to 3NM or 2.5NM.
Please consult the "IFR separation using radar" document to read the
information about the application of this reduced separation.
A controller may, in order to facilitate sequencing or to reduce the
need for vectoring, request aircraft to adjust their speed in a specific
The transfer point, the direction of flight, specified levels, transfer
of communication points and agreed minimum separation between aircraft
have been made the subject of specific instructions or of a specific
letter of agreement between the 2 adjacent ATC units.
When the control of an identified aircraft is to be transferred to a
control sector that will provide the aircraft with procedural
separation, the transferring controller shall ensure that appropriate
procedural separation is established between that aircraft and any
other controlled aircraft before the transfer is affected.
Vectoring is the process for an air traffic controller to issue to the
pilot specific headings which enable the aircraft to maintain the
desired track. When vectoring an aircraft, a controller shall comply
with the following points:
An identified aircraft observed to deviate significantly from its
intended route or designated holding pattern shall be advised
accordingly. Appropriate action shall also be taken if such deviation is
likely to affect the service of the controller
The pilot of an aircraft requesting navigation assistance from an air
traffic control unit shall state the reason.
An aircraft which has been informed that it is provided with ATS
surveillance service shall be informed immediately when the service is
interrupted or terminated.
Pilots shall be informed by the air traffic controller about adverse
weather, in good time to permit the pilots to decide on an appropriate
course of action to circumnavigate the adverse weather area, if so
desired. When vectoring aircraft for circumnavigating an area of adverse
weather, the controller shall ascertain that the aircraft can be
returned to its intended flight path.
The progress of an aircraft in emergency shall be monitored and whenever
possible plotted on the situation display until the aircraft disappears
from the radar system coverage.
Its position information shall be provided to all air traffic services
units which may be able to give assistance to the aircraft.
When an identified controlled flight is observed to be on a conflicting
path with an unknown aircraft deemed to constitute a collision hazard,
the pilot of the controlled flight shall, whenever practicable: *be
informed of the unknown aircraft, and if so requested by the controlled
flight or if, in the opinion of the controller, the situation warrants,
a course of avoiding action should be suggested
When an identified IFR flight operating outside controlled airspace is
observed to be on a conflicting path with another aircraft, the pilot
Information regarding traffic on a conflict path shall be given,
whenever practicable, in the following form:
If two-way communication is lost with an aircraft, the controller shall
determine whether or not the aircraft's receiver is functioning by
instructing the aircraft:
Where it has been established that aircraft's radio receiver is
functioning, continued control can be effected using SSR transponder
code or ADS-B transmission (text communication for IVAO) change or IDENT
transmissions to obtain acknowledgement of clearance issued to the
When a controlled aircraft experiencing complete communication failure
is operating or expected to operate in a controlled airspace, the
controller shall continue to apply adequate separation to all aircraft.
Separation shall be applied between identified aircraft and all
unidentified aircraft observed along the expected route of the aircraft
with the communication failure.
In the event of complete failure of the radar system where voice
communication remains, the controller shall take the necessary action to
establish procedural separation between the aircraft and, if necessary
limit the number of aircraft permitted to enter the area.
As an emergency measure, use of flight levels spaced by half the
applicable vertical separation minimum may be used as a temporary
separation method, if standard procedural separation cannot be provided
The indications presented on the radar system may be used to perform the
following additional functions in the provision of approach control
This last item imposes to ATC not to change the arrival flow due to
departing traffic. Departing aircraft shall not jeopardize the arrival
Prior to vectoring for approach, the pilot shall be advised of the
type of approach and the runway to be used. The controller could
advise an aircraft being vectored for an instrument approach of its
position at least once prior to commencement of the final approach.
Aircraft vectored for final approach shall be given a heading or a
series of headings calculated to close with the final approach track:
The controller is responsible for maintaining separation minimum
between succeeding aircraft on the same final approach except that
the responsibility may be transferred to the aerodrome controller in
accordance with procedures defined by your country regulations and your
IVAO division rules, and if the aerodrome controller has a radar system.
Transfer of control of succeeding aircraft on final approach to the
aerodrome controller shall be done in accordance with procedures
prescribed by your country regulations and your IVAO division rules.
Transfer of communication to the aerodrome controller should be
performed at such a point or time that clearance to land or alternative
instructions can be issued to the aircraft in a timely manner.
This means that transferring an aircraft on short final, or beyond 4NM
from runway threshold is not the right way to perform this transfer.
If there is no procedure, the transfer of control should be done when
the aircraft has intercepted the final approach track but not before
15NM from the runway threshold.
The controller may initiate a vectoring of an aircraft for visual
approach and meteorological conditions are such that, with reasonable
assurance, a visual approach and landing can be completed.
Clearance for visual approach shall be issued only after the pilot has
reported the aerodrome or the preceding aircraft in sight, at which time
vectoring will normally be terminated.
There are two types of radar approaches: Precision (PAR) and
Surveillance (ASR). Controllers conducting radar approach shall be in
possession of information regarding the obstacle clearance
altitude/heights established for the type of approach to be conducted.
(For the IVAO network, each controller shall have charts of their area
In aviation, approach surveillance radar (ASR or SRA) is a type of
radar instrument approach provided with active assistance from air
traffic control. The only airborne radio equipment required for
radar approaches is a functioning radio transmitter and receiver. The
radar controller vectors the aircraft to align it with the runway
centreline. The controller continues the vectors to keep the aircraft on
course until the pilot can complete the approach and landing by visual
reference to the surface.
As these approaches are specific and used mainly in military airfields,
and as the IVAO ATC software is not fully compatible with them,
we do not develop this subject in this document.
When authorized by country regulations and IVAO division air traffic
control operation rules, radar systems may be used in the provision of
aerodrome control service to perform the following functions:
Special VFR shall not be vectored unless under special circumstances,
such as emergencies.
Normal VFR should not be vectored unless under special circumstances
(emergencies, assistance requested by pilot) or specific regulations
depending on the airspace class. The controller shall ensure that the
VFR aircraft vectored does not inadvertently enter instrument
meteorological conditions (IMC).
In real life, the use of an ATS surveillance system like radar will
not be detrimental to visual observation of aerodrome traffic.
But at IVAO, the radar simulated by IVAO ATC softwareis today the
primary method to control an aerodrome airfield due to the better
performance provided by this system than the view created by a
flight simulator system which simulates the external visual observation
of the manoeuvring area.
The IVAO ATC software radar can be used as surface movement radar and
the controller uses it to assist with: The IVAO ATC software Radar can
be used as surface movement radar and the controller uses it to assist
The radar information may be used to provide identified aircraft with: