How-To: Flying
with Air Traffic Control
Getting more out of Multiplayer ATC sessions
Note: This set of Frequently Asked
Questions deals with flying a flight simulator on a
desktop computer. Don't use any of this information to
fly a real plane, and remember that in this FAQ, many
concepts have been simplified, and many more omitted
altogether. This information is intended to help people
get more enjoyment out of flying computer planes in a
multiplayer setting, nothing more...
What is ATC?
- ATC is short for Air
Traffic Control. As you probably know,
airplane pilots can't just hop in the plane and
take off from most airports without talking to an
air traffic controller on a two-way radio.
Controllers use radar to look at airplanes in
flight, and radios to give instructions to pilots.
These instructions come in the form of clearances.
ATC clearances are standardized ways of telling
pilots what to do - which direction to fly, and
at what altitude, for example. More on clearances
in a bit...
The air traffic control system helps keep planes
from running into each other, and brings order to
the skies. The ATC system is very highly-regulated,
but for the purposes of Multiplayer (MP) flying,
can be simplified so that armchair flyers (don't
you hate that expression?) can get a better feel
for what it might be like to fly for real.
In the real world, there are many levels of air
traffic control, from Ground Control, to Tower,
to Approach and Departure, and enroute control at
a terminal or air traffic control center. Enroute
air traffic control consists of overflights that
are handed off to a controller who watches the
flight until it is time to hand it off to another
controller.
How does ATC work with a flight sim Multiplayer
session?
- There is no
single way or method of using ATC in a FS
Multiplayer session. In FS98, the simplest way to
provide ATC is for the controller to use the map
view to look at the other planes, and a voice
communications program such as Roger Wilco, to
talk to them. The controller may act as a VFR, or
Tower controller, or as Tower and Approach /
Departure controller. It can be as simple as
saying "Cleared to land," and "Cleared
takeoff," and nothing more, or as complex as
a full-blown CH Server / Client session requiring
special software add-ons. It is up to the person
hosting the session as to what level of ATC
service he or she is willing to provide.
Capabilities and skill levels of the controller,
as well as the pilots, are a big factor in
whether Multiplayer ATC works well or not.
What is VFR? IFR?
- VFR
is short for Visual Flight Rules,
and IFR is short for Instrument
Flight Rules. Under VFR, airplanes must
remain in visual contact with the ground, and are
responsible for seeing other airplanes in the
air, and avoiding them. You might think, "Hey,
it's up to ATC to keep the airplanes from hitting
each other." But under visual conditions,
pilots of big and small airplanes are always
required to search the skies for, and avoid,
other airplanes.
Many VFR flights can proceed without the need for
the pilot to talk to an air traffic controller at
all. At small airports where there is no control
tower, and in uncontrolled airspace, a VFR pilot
can pretty much go where he or she pleases,
subject to real-life restrictions that don't much
concern us here. One restriction that would apply
to a VFR flight is weather - if you can't see
where you are going because of weather, then you
probably shouldn't be there...
An IFR flight is under positive
control of the ATC system at all times. All IFR
flights follow flight plans, which are filed with
ATC. Among other things, flight plans contain the
route the aircraft will fly. The pilot flies the
route, and ATC watches the flight on radar. As
the aircraft moves between sectors and passes out
of radar range, different controllers will take
over. To find their way around, IFR pilots use
navigation instruments installed in the aircraft,
and don't need to look at the ground to navigate.
These instruments get data from ground-based
navigational aids, and display the information to
the pilot. The pilot uses maps, charts, and
instrument approach plates, together with the
instruments, to follow a specific air route. An
IFR flight could theoretically proceed from
takeoff to touchdown without the pilot ever
talking to an air traffic controller.
What types of clearances are there?
- At larger
airports, a departure clearance
is issued by a Clearance Delivery controller
while the aircraft is still parked. An IFR
departure clearance is based on your flight plan
- for VFR flights without a flight plan,
Clearance Delivery will assume you are flying a
local sightseeing or training flight, and will
simply tell you which runway to expect, then
clear you for engine start and tell you to
contact Ground Control.
Smaller airports will probably not have a
Clearance Delivery controller, so the pilot would
contact Ground Control before starting engines.
If there is no Ground Control position, the pilot
would talk to Tower. If there is no Tower, the
pilot would say his or her intentions over the
Unicom frequency before taking the runway. Unicom
is a common traffic frequency that all VFR
flights in the area would listen to. Air traffic
control services are not provided on Unicom
frequencies, but it is still possible for an IFR
flight to depart from a VFR-only airport with no
tower. As long as visual conditions exist, the
pilot can file an IFR flight plan with a Flight
Service Station (FSS) over the telephone and
contact ATC in the air, either an enroute Center
or Departure control from a nearby larger airport.
The flight is then under control of the IFR
system.
A departure clearance will include the runway to
be used, and for IFR flights, the specific route
the aircraft will be taking to its destination.
This routing will include any amendments or
changes that ATC has made to that route as filed
by the pilot in the flight plan.
A taxi clearance is issued by a
ground controller once the aircraft is ready for
engine start. This clearance will tell the pilot
which taxiways to use to get to the desired
runway for departure, and includes hold short
instructions for runways, which must be read back
by the pilot. "Hold Short" means, don't
cross or enter the runway without permission.
"Taxi into position" means, taxi onto
the runway and wait there for your takeoff
clearance. In a MP ATC session, you shouldn't
enter the runway, much less take off, wihout a
clearance.
A takeoff clearance will be
required at any airport where there is a control
tower, and is normally issued by the Tower
controller. "Cleared for takeoff,"
along with the runway number, means you are
cleared to take off from that runway. In a MP
session, you should have an idea of what you want
to do, i.e. remain in the circuit or traffic
pattern, do some local sightseeing, or fly to
another airport. You should tell Tower what you
want to do, at the time you are requesting
clearance to taxi or take off.
Tower will issue a landing clearance
when your aircraft is in a position to land, and
the runway is clear. In a MP ATC session, you
shouldn't land without a clearance.
What are patterns? Circuits?
- The pattern
generally refers to the traffic flow
that is in use, or has been established at a
particular airport. A circuit generally means a
trip around the pattern. These terms are often
used interchangeably, i.e. "In the pattern"
or "In the circuit." In Canada, the
standardized path to be flown by aircraft in the
vicinity of an airport is called the circuit, and
in the US, it is called the pattern. You can
visualize a typical airport traffic pattern as a
rectangular box shape, aligned over the main
runway. Turns in the pattern are usually to the
left, and the pattern is usually flown at around
1,000 feet above ground level. At least one leg
of the pattern is normally flown by inbound VFR
aircraft, and student pilots can often be found
flying the pattern over and over and over...
VFR pilots arriving at an airport are expected to
be able to visually navigate and
maneuver their aircraft into position for
landing, without receiving specific directions (headings
or vectors) from the Tower - only a clearance to
enter the control zone, a clearance into the
pattern, and a clearance to land is usually
required. In the real world, if you want to fly
into an airport, you are supposed to know the
various runway headings and the airport elevation
in advance, so all you need to know when you want
to join the pattern is, which runway is active at
the time, plus winds. Until you get good at
quickly calculating downwind and base leg
headings in your head, or get used to a certain
airport, flying the VFR pattern can be harder
than it looks...
In the flight sim world, we don't always have the
proper maps, charts and facility directory, so we
have to make do, and improvise. If you want to
join an ATC session, you should at least know the
bare minimum about the airport you want to fly
into - you can get the runway headings and
elevation from the FS facility directory, or if
you are using scenery that is not part of the
program, from the Internet.
In any case, a VFR arrival, upon receiving a
clearance to enter the traffic pattern, would fly
a predictable, standardized path
around the airport that would lead to a normal
approach and landing.
In order to expedite traffic flow,
Tower will often clear an aircraft directly to a
leg of the pattern. For example, looking at the
diagram above, an aircraft arriving from the
northeast, or the upper right-hand corner of the
picture, might be cleared to a left-hand downwind
for the runway (we'll call it Runway 09). An
aircraft arriving from the northwest, or the
upper left, could be cleared to a left base for
Runway 09. An aircraft arriving from the south
would have to join the crosswind leg, while an
aircraft arriving from the west, would have the
farthest to fly of all, and would normally join
the upwind leg.
You might ask why an aircraft arriving from the
west would have to fly the pattern, when it could
just descend and land straight ahead. The answer
is, flying a straight-in approach when VFR can
make it harder to judge perspective and distance
from the airport, and is especially discouraged
at fields where there is no tower. It is better
to join the circuit, where it is possible to see
the windsock while flying around the airport, as
well as look at the condition of the runway, etc.
Some busier airports have published VFR
arrival routes that incorporate local
landmarks such as bridges, chimneys, water
towers, stadiums, etc. It makes it easier for
Tower to ask an aircraft to report over the local
water tower on the left base for the active
runway, even before the aircraft has entered the
control zone. In the real world, if a pilot has
never flown into an airport before, he or she can
always ask Tower for a little extra help in
identifying ground references or runways - this
is not recommended at the large, busy airports,
however, where you should be prepared if you want
to play in the "big leagues..."
Tower will normally clear an aircraft in the
pattern to visually sight and follow a preceding
aircraft, and will also advise of any IFR or VFR
traffic that could be a factor in seeing and
avoiding. In good weather (the only time VFR
aircraft are supposed to be active), IFR pilots
are also supposed to watch for other traffic, but
may tend not to look outside the airplane as much
as a pilot flying VFR.
What a real-world Tower will not normally do, is
issue heading changes and speed restrictions to
aircraft. If you are unfamiliar with the area,
Tower can provide suggested headings to fly, but
will not issue radar vectors. In a Multiplayer
session, however, the controller may decide to do
just that, and if you want to play, you should go
along with it. In FS98, it is often harder to
judge perspective, runway layout and distance to
the runway, especially at unfamiliar airfields,
than in a real aircraft. This is where ATC
vectors can really come in handy...
Do IFR arrivals always fly an IFR approach?
- No. At some
airports, it is standard for inbound IFR's,
airliners, etc. to receive a clearance to fly a
left or right-hand, or straight-in visual
approach to the active IFR runway. In
clear weather, pilots checking in with approach
control are issued radar vectors to a point close
to the airport, at which time the pilots are
asked whether they have the airport in sight.
When they do, the visual approach clearance can
be given. If there is traffic ahead, they are
asked if they have the preceding traffic visually
before they are handed off to Tower. Note that
the flight is still an IFR flight until the
flight plan is cancelled with the appropriate ATC
agency, but as always in visual conditions, the
pilots are required to look out the window for
other aircraft.
Why does ATC give out visual approaches to IFR
inbounds? Mainly to save time and gas. The
airlines like saving gas, and the pilots
especially like saving time. It is also less of a
headache for ATC to be able to pass along some of
the responsibility for navigating, and seeing
other traffic, to the pilots. The time and gas is
saved because an aircraft that will be flying an
ILS approach must be vectored to a 10 or 15-mile
final, while an aircraft that has accepted a
visual approach can be directed to turn final at
the outer marker, just four or five miles out.
Why is it so hard to fly the big jets in the
pattern?
- Hard is a relative
thing. In the flight sim world, flying a visual
approach in an airliner requires different
techniques than flying the ILS, or flying
patterns in a smaller plane. It can be a
challenge to maneuver a large aircraft onto a
five-mile final - the views out the windows are
not as good and it is easy to lose sight of the
runway, overshoot or undershoot your turn, or to
get your perspective messed up. Many Flight Sim
pilots do not practice flying circuits, and don't
practice hand-flying the larger aircraft, which
is why radar vectors to the ILS approach seems to
be the rule in many sessions. But it's a
worthwhile skill to be able to fly visual
approaches in the big jets, and it can be a lot
easier to do if you keep a few things in mind:
- Don't take
it out too far. If you fly out too far
in any direction, you will lose sight of the
airport, or lose your visual perspective relative
to the runway. Try climbing straight out to 1,500
feet, then turn crosswind while levelling out
your rate of climb. Don't spend too much time on
the crosswind leg - as soon as you are
established 90 degrees from the runway heading,
start your turn downwind. In flight sim, airports
and runways will often disappear from view sooner
than they would in real life. You will probably
have to make somewhat steeper turns than a real
airliner would to compensate for this, so you can
stay close enough to the airport to keep it in
sight. Just keep it within reason, and fly high
enough (2,000 to 2,500 AGL) so you don't lose the
airport visually. It takes practice and
experience to judge how much room you will need
to turn a 747 - try an A-320 and take it from
there.
- Fly at a
reasonable airspeed. There is no reason
to fly a large aircraft at more than 200 knots
when close to the airport. If you fly any faster,
you will probably get too far from the airport
and lose your orientation to the runway.
Naturally, you will have to configure the
aircraft for slower flight. Find and use a flap
setting that will give you good visibility over
the panel, and a good margin of safety above the
aircraft's stall speed. It is good practice to
keep your speed up on final - try flying at 180
knots or so until five miles final, or at the
outer marker, then smoothly reduce to final
approach speed. Approach Control will sometimes
ask you to "keep the speed up" or to
reduce to minimum approach speed, to help with
sequencing, and they will appreciate it if you
can comply.
- Keep the
patterns consistent. Try to do it the
same way every time, with the same aircraft,
until you are familiar with how the airport looks
from all angles. Then you can vary your airspeeds
and try it with different aircraft.
- Turning
final can be tough to nail
The single most difficult thing to get right is
the turn from base to final - it is hard to know
exactly when to start your turn. Turn too early
or too late and you will not have much time to
get properly lined up with the runway. A good
landing will only result from a stable, well-aligned
approach, and judging when to start your turn can
only come from experience with flying a
particular aircraft. The weight of the aircraft,
the altitude and airspeed, the winds, and the
"look" of the airport and scenery on
the approach, will all be factors. Get used to
doing it a certain way before you change
anything, and get used to judging your distance
from the runway on downwind and when turning base.
Pick an ILS runway with DME to start, and use the
DME readout, along with your out-the window
views, to develop skill in estimating your
distance from the runway. When you get to the
point where you can consistently turn a large
airplane like a 767 onto a five-mile final, then
try it at another airport, or with another
aircraft. If you can't get to that point, then
practice with smaller aircraft, and smaller
patterns, until you are ready to move up.
Can a VFR aircraft fly an IFR approach?
- Yes, a simulated
ILS approach, for example, can be flown on
request by a VFR pilot, and traffic permitting,
ATC will likely approve it. But the aircraft is
not part of the IFR system, and must remain VFR
at all times, i.e. clear of clouds, and the pilot
is responsible for separation from all other
aircraft. This type of flying can obviously be
done only in clear weather, and is usually done
as part of training. In that case, there will be
two pilots on board, and the instructor will be
able to keep looking out the window for traffic,
talk on the radio, etc.
What are vectors?
- At airports for
which a published instrument approach exists, and
where Arrival or Approach control is provided,
rather than have inbound aircraft fly the full
published approach, radar vectors are normally
issued to bring aircraft into position to carry
out the final approach phase. Since flying a full
published approach requires things like procedure
turns and outbound and inbound legs, this saves
both time and fuel.
Radar vectors are also issued to aircraft flying
in, or near, an airport traffic area, so that ATC
can provide for aircraft separation in the radar
environment. These can be issued by the Approach
or Departure controllers, and consist of
instructions to fly a particular heading. IFR
pilots can also normally expect altitude and
speed restrictions along with their clearances.
Speed restrictions are given in multiples
of 10, i.e. "Maintain 180 knots or
better to the marker," not
"maintain 175 knots." The same is true
for vectors - aircraft are cleared to turn either
left or right to a compass heading that is a
multiple of 10, so it would be, "Turn left
to 090 degrees," not "Turn to 087
degrees." The exception might be when a
Multiplayer or CH controller is "talking"
a pilot through a full published approach. That
would be unusual, and would not happen in the
real world.
In FS98 Multiplayer flights, it is difficult to
use the FS map view to provide radar vectors, for
example, to an ILS approach. It can be done, but
not very precisely. And it is easier to do for
smaller aircraft, which can turn in a much
smaller area than large aircraft, and are less
likely to overshoot the localizer. CH
Server / Client is much more suited to
this type of session.
Finally...
- There is a fundamental
difference between how VFR and IFR
flights get handled in the real world, a
difference that often gets blurred in Multiplayer
ATC sessions. This is why you can sometimes find
youself getting "vectored" around the
traffic pattern, with Tower calling each turn for
you with headings and airspeed restrictions, or
alternately, clearing you to land on an ILS
approach before you have even intercepted the
localizer. It's up to the person hosting an ATC
session to sort out how the session is going to
run, and this is where communication comes in
handy, in the form of adding more detail to the
flight board posting. For pilots, knowing in
advance whether VFR or IFR type flying, or both,
will be taking place, can reduce confusion and
help streamline the session for everybody.
To sum this FAQ up, the success of any
Multiplayer or CH session depends on keeping
procedures as simple and straightforward as
possible, and on the controller and pilots not
exceeding the limits of their abilities. It is
possible to have an enjoyable, fun ATC session
using only the basics, such as those covered in
this FAQ.
Happy flying...
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