TOWER STUDY GUIDE
Issue No. 003
23 June 2003
Richard
Durocher, VATCAN Director
Steve
Talmadge, VATCAN Training Director
Not for
real-world training
Section 3 – INITIAL CONTACT AND POSITION
DETERMINATION
Section 4 – ADVISORIES AND TRAFFIC
INFORMATION
Section 5 – AIRSPACE RESTRICTIONS
Section 6 - TAKEOFF CLEARANCES
Section 8 – SEPARATION and SPACING - GENERAL
RULES
Section 9 – GENERAL DEPARTURE PROCEDURES
Section 10 – DEPARTURE SEPARATIONS
INTRODUCTION
This Study Guide provides basic information necessary
to work VATCAN Tower (TWR) positions.
It builds and expands on the information presented in the VATCAN Basic
and Ground Control Study Guides. This Guide is to be used only on the VATSIM
network.
Real-life Tower controllers
manage aircraft based primarily upon what they see outside control tower
windows. Application of separation
standards depends on seeing the aircraft and other visible landmarks.
Real-world Tower radar displays are only an aid. When running Pro Controller
and ASRC your radar display, supplemented by pilot reports, becomes your
primary tool.
Section 1 – RUNWAY SELECTION
a)
Tower normally selects the active runway(s). However, at some aerodromes (due to
proximity of nearby aerodromes or other factors), Arrival/Approach Control may
select the active runway(s). Remain
flexible and consider the impact on other controllers when selecting and
coordinating active runways.
1)
When the wind is 5 knots or more select the active runway
most nearly aligned with the wind.
2)
When the wind is less than 5 knots use the "calm
wind" runway if one is designated.
3)
Operational factors may make another runway less aligned
with the wind more suitable. Reasons
for selecting a different runway could be the availability of instrument
approaches, length, noise abatement, or other factors.
4)
You may use a runway other than the active runway(s) if it
will be operationally advantageous or is requested by the pilot. Some examples would be: Assigning large aircraft to the active
runway(s) and smaller aircraft to another runway, if a pilot requests a
straight-in approach to a runway other than the active runway(s) or requests a
runway that is closer to his parking area.
b)
State the active runway when using another runway eg “Wind
is xxx/xx, RUNWAY 28L CLEARED TO LAND”
Section REVIEW
EXERCISE
Obtain
the current weather and runway data for at least five aerodromes. Select the active runway(s).
Section 2 – COORDINATION
a)
In addition to concepts presented in the Basic and Ground
Control Study Guides, TWR has its own unique coordination requirements.
b)
When you authorize Ground Control to issue crossings of an
active runway, use the word “CROSS” and
the runway number, eg “CROSS RUNWAY 36.”
In real-life each individual crossing must be coordinated. In Pro Controller or ASRC blanket approval
is frequently given to GND to cross active runways when he sees it is safe to
do so. Inform GND of the type of crossing coordination you wish to use.
c)
Before you use any runway not previously designated as
active you must coordinate with GND to make sure he doesn’t have any aircraft
taxiing on it.
d)
Coordinate with ARR/APP to determine what type instrument
approach arrivals will be making, handoff points, unplanned missed approach
instructions, Class B or C Airspace procedures, and any other local
requirements.
e)
Coordinate with the controller running DEP (could also be
ARR/APP, or CTR) to determine the initial SID, vector or routing for
departures, IFR release procedures (individual or automatic), and initial
separation for successive departures.
Section REVIEW
EXERCISES
Log
on to Pro Controller or ASRC as TWR or observer, set your range to show no more
than 30 NM and note the size of the runways depicted by the radar map.
Consider
under what circumstances you would use individual and blanket runway crossing
approval.
Observe
departures and note how long it would take to obtain a successive departure
separation of 5 NM, 10 NM, or 20 NM.
Section 3 – INITIAL CONTACT AND POSITION DETERMINATION
a)
When working TWR (as when working Ground), provide aerodrome traffic control service on
the basis of known or observed conditions. This is more difficult in Pro
Controller or ASRC than in real-life.
You cannot look out the window and must rely on your radar display,
pilot reports, and your own common sense.
b)
Before controlling an aircraft, you must know where it is
located. Just as in Ground Control,
issuing control instructions without being sure of an aircraft’s position could
easily create a conflict. While aircraft positions on radar are generally
accurate enough, pilots may be unsure of their exact location. Use caution when relying on aircraft
position reports alone.
c)
Airborne pilots are required to establish communications
before entering the Class D airspace. If you respond to a radio call with
"(CALLSIGN) STANDBY" communications have been established and the
pilot may enter Class D space. If you
want the aircraft to remain outside the Class D you must say so eg “(CALLSIGN)
REMAIN OUTSIDE DELTA AIRSPACE AND STANDBY.”
Section REVIEW
EXERCISES
Log
on to Pro Controller or ASRC and ask several aircraft for position reports.
Note any differences between them and the radar position of the aircraft.
Observe
aircraft as they land and take off.
Watch their altitude readout.
Compare it to the runways shown on the radar map and estimate where the
landing threshold is.
Section 4 – ADVISORIES AND TRAFFIC INFORMATION
a)
Issue information about the aerodrome necessary for an
aircraft's safe operation in time for it to be useful to the pilot. While not likely to be encountered in Pro
Controller or ASRC, this would include information on construction, less than
normal braking action, or other pertinent aerodrome conditions.
b)
When describing any observed abnormal aircraft condition
always use the term “APPEARS”, eg “IT APPEARS YOU HAVE LANDED ON THE WRONG
RUNWAY.” This is especially useful in
Pro Controller or ASRC because what the pilot sees on his computer may not
exactly match what you see.
c)
All vehicles, equipment, and personnel must be off the
runway before a departing aircraft starts takeoff roll or a landing aircraft
crosses the landing threshold. The only
positive way to ensure this is by requiring these vehicles, etc to maintain
radio contact with the control tower at all times. They may only enter the runway with permission from the tower and
must exit and report off when instructed.
d)
When vehicles, equipment, or personnel are on the runway,
aircraft may still make low approaches to that runway if they are restricted to
at least 500 feet above the aerodrome elevation, eg aerodrome elevation = 300
ASL “CLEARED FOR LOW APPROACH AT OR
ABOVE 800 ASL, VEHICLE ON THE RUNWAY.”
e)
Vehicles, equipment, and personnel in direct communications
with the control tower may be authorized to operate up to the edge of the
runway, but not actually on it, if you issue an advisory to the aircraft, eg
“MEN AND EQUIPMENT RIGHT SIDE OF RUNWAY.”
f)
Advise other aircraft of the runway braking action when
reports are received from pilots. While reduced braking action is not currently
modeled in Flight Simulator know how to
handle any reports you may receive from pilots or observe in the REMARKS section
of a METAR.
g)
Describe the quality of braking action using the terms
"GOOD" "FAIR" "POOR" or "NIL" and
include type of aircraft eg “BRAKING ACTION POOR, REPORTED BY A 727.” If the
pilot report uses different words, ask him to restate braking action in these
terms.
h)
Describe traffic in an easy to understand manner, such as
“TO YOUR RIGHT” or “AHEAD OF YOU” eg “TRAFFIC, A320 ON DOWNWIND TO YOUR
LEFT.” Avoid using cardinal directions
(north, south, etc) or referring to landmarks such as “past the fire station”
or similar objects the pilot may not be familiar with or may not be included in
his scenery.
i)
Issue traffic in the standard radar traffic advisory format:
12-hour
clock position or cardinal direction (N, S, E, W).
Distance in miles.
Direction
of movement.
Type
and altitude if known.
j)
Examples:
“TRAFFIC, YOUR 11 O'CLOCK, 10 MILES,
SOUTHBOUND, DC-8, 17,000.”
“TRAFFIC, YOUR 12 O'CLOCK, 15 MILES,
OPPOSITE DIRECTION, ALTITUDE UNKNOWN.”
k) When the traffic is no longer a factor or depicted on radar inform the pilot eg “TRAFFIC NO FACTOR/NO LONGER OBSERVED.”
Section REVIEW
EXERCISES
Log
on as an observer at a busy sector.
Practice issuing traffic advisories in the easy-to-understand and radar
formats.
Section 5 – AIRSPACE RESTRICTIONS
a)
If an aircraft requests to takeoff, land, or touch-and-go on
a closed or unsafe runway, inform the pilot the runway is closed or unsafe, and
inform him that a clearance cannot be issued.
b)
If the pilot persists in his request and traffic is not a
factor, inform him that the operation will be at his own risk eg “RUNWAY 36
CLOSED. ATC CLEARANCE CANNOT BE ISSUED,
DEPARTURE/LANDING/TOUCH-AND-GO WILL BE AT YOUR OWN RISK.”
c)
Do not approve a speed in excess of 250 knots below 10,000
ASL unless necessary due to the minimum safe speed of
the aircraft, previously coordinated (military), or on departure. Below
3,000 AGL within 10 nm of a controlled aerodrome, aircraft are restricted to a
speed no greater than 200 KIAS.
d)
Note: On departure, an
aircraft may fly at any speed.
e)
Do not approve unusual maneuvers such as “buzz jobs” where a
flight is conducted at a low altitude or high speed for thrill purposes within
Class B, C, or D airspace if they are not essential to the performance of the
flight unless covered in a local Standard Operating Procedure or Letter of
Agreement.
Section REVIEW
EXERCISE
Consider what you would do if an aircraft requested to exceed 250 knots or to practice aerobatics in your Class D Airspace.
Section 6 - TAKEOFF CLEARANCES
Issue a take-off clearance in the following form:
Aircraft
Identification
Unit
Identification, if required
Special
Information, such as a hazard or instruction
Control Information,
such as a turn after takeoff
Wind
Information, if winds are over 15 Kts.
Cleared for
Take-off
Example: “SAC007, on departure fly heading 250, winds
210 at 19, Cleared for Take-off Runway 23.”
Section 7 – WAKE TURBULENCE
a)
Wake turbulence is generated by the passage of an aircraft
through the atmosphere. Generally
speaking the heavier the aircraft the more wake turbulence. The term also includes vortices, thrust
stream turbulence, jet blast, jet wash, propeller wash, and rotor wash both on
the ground and in the air.
b)
Wake turbulence may be encountered by aircraft on the ground
as well as in flight. Because wake
turbulence is unpredictable, controllers are not responsible for anticipating
its existence or effects. Wake
turbulence isn’t currently modeled by FS so pilots won’t experience its effects
but as a controller you are still required to provide the appropriate wake
turbulence separation.
When discussing wake turbulence separation, aircraft are classified as Heavy, Medium or Light. Aircraft classifications are based upon maximum takeoff weight - whether or not an aircraft is operating at this weight during any flight phase.
Heavy aircraft are aircraft certificated for a
maximum takeoff weight of 136,000 kilograms (300,000 pounds) or more. Some
examples are most 707/C-135, all 747, 767, DC-10, L-1011, A-300, A-340, C-5,
C-141, C-17, and B-52 aircraft.
When discussing wake turbulence, Boeing 757
Aircraft are treated as heavy when the 757 is the preceding (leading)
aircraft. When the 757 is the following aircraft it is treated as a medium
aircraft.
Medium
aircraft
are certificated for a maximum takeoff weight of more than 5,700 kilograms
(12,500 pounds), but less than 136,000 kilograms (300,000 pounds).
Light aircraft are certificated for a maximum takeoff
weight of 5,700 kilograms (12,500 pounds) or less.
c)
Apply wake turbulence procedures to departing aircraft as
follows:
Light or Medium behind Heavy - 3
Minutes
Light behind Medium - 3 Minutes
Any aircraft departing behind Heavy
aircraft where the flight paths will cross - 2 Minutes
d)
Apply wake turbulence procedures to aircraft arriving behind
Heavy jets and, where indicated, Light aircraft behind Medium aircraft. Wake turbulence arrival and separations for
aircraft operating directly behind and/or less than 1,000 feet below a
preceding aircraft are enforced as follows:
Heavy behind/below a Heavy – Four Miles
Light behind/below a Medium – Four Miles
Medium behind/below a Heavy – Five Miles
Light behind/below a Heavy – Six Miles
e)
Separation shall continue to touchdown for all IFR aircraft
not making a visual approach or maintaining visual separation.
f)
Issue wake turbulence cautionary advisories, eg “CAUTION
WAKE TURBULENCE” to:
VFR aircraft
arriving behind a Heavy or B757.
IFR aircraft
on visual approach or visual separation behind a Heavy or B757.
Any aircraft
if in your opinion wake turbulence may have an adverse effect on it.
Section REVIEW
EXERCISES
Log on to Pro Controller or ASRC as an observer and note the aircraft categories of the aircraft currently in the system.
Section 8 – SEPARATION and SPACING - GENERAL RULES
a) Control of the VFR traffic patterns and runways is the primary duty of the Local Controller.
b)
The components of a normal
rectangular traffic pattern are:
Upwind, parallel to
the runway, in the direction of landing – not normally used.
Crosswind, at right
angles to the departure end of the runway.
Downwind, parallel to
the runway between crosswind and base, opposite to the landing direction.
Base, at right
angles to the approach end of the runway from downwind to the extended runway
centerline.
Final, along the
extended runway centerline from the base leg to the runway in the direction of
landing. An aircraft making a straight-in is considered to be on final.
c)
TWR controllers establish the sequence of arriving and
departing VFR aircraft.
d)
Pilots should be instructed to adjust their traffic pattern
to achieve desired entry, spacing and flow:
e)
Examples -
Entry: “ENTER DOWNWIND” “ENTER BASE” “MAKE STRAIGHT-IN” “ENTER INITIAL”
Spacing: “EXTEND DOWNWIND” “MAKE SHORT APPROACH” “MAKE A 360 ON DOWNWIND” “MAKE A 270 TO BASE” “BREAK DEPARTURE END”
Flow: “NUMBER 2 FOLLOW 727 ON
BASE” “NUMBER 4 FOLLOW C-172 ON
DOWNWIND.” If the traffic is using a
different runway do not use the term “FOLLOW” but state the runway the other
aircraft is using, eg “TRAFFIC IS A LEAR 45 ON BASE LANDING RUNWAY 36.”
f) Left turns (traffic) are standard. Aircraft may be instructed to make right turns or right traffic may be published for the specific pattern.
g) Normal VFR rectangular pattern altitudes in Pro Controller or ASRC are 1000 AGL for fixed-wing aircraft and 500 AGL for rotary-wing aircraft.
Separation
Fixed-Wing Aircraft - Same Runway:
Separate aircraft from preceding aircraft using the same runway ensuring that
an arriving aircraft does not cross the landing threshold until one of the
following conditions exists:
The
preceding. landing aircraft has landed and taxied off the runway, or
The
preceding, departing aircraft is airborne and is a sufficient distance from the
threshold that the arriving aircraft will not overtake it during the landing
roll or conflict with it in the event of a missed approach.
Separation
of Fixed-Wing
Aircraft - Runway or Flight Path Intersection: Separate
departing aircraft from aircraft using an intersecting runway, or
non-intersecting runway if flight paths intersect, by ensuring that the
departing aircraft does not begin its take-off roll until one of the following
conditions exists:
a) Preceding
departing aircraft has:
passed the
intersection,
crossed the
departure runway, or
turned to
avoid any conflict.
b) Preceding
arriving aircraft has:
taxied off the
landing runway,
completed the
landing roll and will hold short of the intersection,
passed the
intersection, or
crossed over
the departure runway.
Separation
- ROTARY-WING Aircraft
a)
Issue take-off or landing clearance to a rotary-wing
provided the operation takes place on the manoeuvring area.
b)
Because of their operational characteristics, it is not
always necessary that rotary-wing aircraft adhere to the standard traffic
circuit, land or take off on the same runway or follow the flight path used by
fixed-wing aircraft. In IFR weather conditions, however, rotary-wings
conducting IFR flights are expected to climb out from or approach to an
instrument runway. They may, of course, originate from or terminate at other
locations on the airport via airborne or ground taxiing.
c)
An area other than a runway or taxiway may be designated as
manoeuvring area by the airport manager if it has been approved by the
responsible Regional authorities.
d)
Include the specific route in a clearance to or from the
landing area to ensure safe conformance with, or avoidance of other airport
traffic, as necessary.
e)
Clear rotary-wing aircraft to air taxi unless: the aircraft
has specifically requested clearance to hover taxi or taxi on the surface; or
Air Navigation System Requirements direct that rotary-wing aircraft are to taxi
only via the hover mode in specified situations.
f)
Do not issue an air taxi or hover taxi clearance that will
knowingly require a rotary-wing aircraft to pass over persons, vehicles, or
aircraft.
g)
Include explicit route details in an air taxi or hover taxi
clearance, if necessary, due to traffic or known ground hazards.
h)
Apply appropriate wake turbulence procedures to rotary-wing
aircraft during air taxi or hover taxi as though they were departing aircraft.
i)
Avoid frequency changes by rotary-wing aircraft known to be
single-piloted while air taxiing, hovering or flying at low level.
Non-Standard
Arrivals: An aircraft making a touch-and-go, stop-and-go, or low
approach is an arrival until it touches down (Touch and Go), makes a complete
stop (Stop and Go), or crosses the landing threshold (Low Approach). Once a Low
Approach crosses the landing threshold, it is considered a departure.
“CLEARED FOR
THE OPTION” allows the pilot to choose between a full-stop,
touch-and-go, stop-and-go, or low approach.
If necessary to restrict one of these options , e.g. a stop-and-go, use
the phraseology “UNABLE STOP-AND-GO, OTHER OPTIONS APPROVED.”
Clearance for touch-and-go, stop-and-go, low approach, or the option are
considered landing clearances.
Overhead Pattern Arrivals - Used primarily by military fighter-type aircraft. Overhead pattern altitude is normally 1500 AGL.
An overhead
pattern consists of an Initial leg in the direction of landing along the
extended runway centerline, a 180 degree turn (“break”) over the approach end
(the “numbers”), a second 180 degree turn at base, and a final approach. Speeds on the initial leg vary but are
normally around 300 knots.
IFR aircraft
entering the Overhead Pattern are considered VFR when the aircraft reaches
Initial.
Observe
caution when instructing aircraft using an Overhead Pattern to break at any place
other than the numbers. Doing so may
create a conflict with departing or missed approach aircraft.
Section REVIEW
EXERCISES
Compute pattern altitudes AGL and ASL for rotary-wing
aircraft, fixed-wing rectangular, and Overhead Pattern for your aerodrome.
Add together the number of miles flown by an aircraft in the
VFR traffic pattern from take off to landing then add one mile. This is your sequencing cut-off for aircraft
in the VFR pattern. If traffic on final
is farther out than your cut-off it is number 2 in sequence; equal or closer
then it is number 1.
Section 9 – GENERAL DEPARTURE PROCEDURES
a)
When the aircraft calls ready and traffic permits, issue
takeoff clearance. When more than one runway is active, first state the takeoff
clearance followed by the runway number, “CLEARED FOR TAKEOFF, RUNWAY 27L”
b)
Taxi aircraft into Position
and Hold only when takeoff clearance cannot be issued because of traffic,
eg “RUNWAY 36, TAXI INTO POSITION AND HOLD.”
1)
The most common use of Position and Hold is when a preceding
arrival has not yet exited the runway or prior departure separation. Whenever
possible aircraft should be issued takeoff clearance holding short of the
active runway.
2) “Position and Hold” precludes low approach, touch-and-go, and other similar operations on the same runway – that is, allowing one aircraft to fly over an aircraft holding in a departure position on a runway.
3)
Do not use conditional phrases such as “BEHIND LANDING
TRAFFIC” or “AFTER THE DEPARTING AIRCRAFT” when taxiing aircraft into
position. Wait until the other aircraft
is no longer a conflict before issuing instructions to taxi into position.
4) Do not taxi aircraft into an intersection Position and Hold at night. Be flexible when applying this rule in Pro Controller or ASRC. Night visual clues are not as complete as daytime visual clues for real-world controllers but this phenomenon does not carry over into Pro Controller or ASRC. Some simulator pilots operate on a “simulator time” which may be different from the local VATCAN time. Hence, your “night” may be the pilot’s “day” or some variant thereof.
5)
For a runway where the taxiway used does not intersect at
the departure end of the runway the aircraft must taxi along part or all of the
runway. The phraseology would be “BACKTRACK RUNWAY27L AND WAIT”.
c)
Handoff all departing IFR aircraft to the controller
performing the departure control function (DEP, APP, or CTR) as soon as the
aircraft appears airborne. The handoff should be completed before the aircraft
is approximately ½ nm off the departure end of the runway.
d)
VFR departures in Class B and C Airspace and Controlled VFR
departures are handled in the same manner as IFR departures.
e)
Do not request departing military aircraft to make radio
frequency or transponder changes before the aircraft reaches 2500 AGL.
VFR Departures:
There are two ways to handle VFR departures in Class D
airspace:
Instruct the aircraft to depart in a cardinal direction (N,
S, E, W) eg “NORTHEAST DEPARTURE APPROVED.”
Instruct the aircraft to depart via a leg of the traffic
pattern, eg “MAKE RIGHT DOWNWIND DEPARTURE.”
Rotary-wing Aircraft Departures:
a) When a rotary-wing aircraft requests departure from any point on the movement area issue takeoff clearance “CLEARED FOR TAKEOFF.”
b)
When a rotary-wing aircraft requests departure from a
non-movement area use the term “PROCEED AS REQUESTED.”
c)
When a rotary-wing aircraft requests departure from an area
not authorized for rotary-wing use or an area off the aerodrome use the term
“DEPARTURE WILL BE AT YOUR OWN RISK.”
d)
Unless requested by the rotary-wing pilot, do not issue
downwind takeoffs if the tailwind exceeds 5 knots.
e)
Cancel takeoff clearance if circumstances require, eg
“TAKEOFF CLEARANCE CANCELLED” Once an aircraft has started takeoff roll, cancel
takeoff clearance only for safety reasons using the instruction: “ABORT
TAKEOFF”
Section REVIEW
EXERCISES
Log on to Pro Controller or ASRC and practice applying these
procedures while controlling aircraft.
Section 10 – DEPARTURE SEPARATIONS
Separation of IFR departures in the air is the
responsibility of the controller performing the departure function (could be
DEP, ARR/APP or CTR). Tower must obtain
a release from the DEP controller for each departure or provide the separation
specified by the departure controller in addition to applying runway separation. Many FIRs have SOPs or LOAs which cover
departure releases and separations. If
there is no SOP or LOA or the departure controller doesn’t specify any required
separation, ensure at least 5NM between successive IFR departures.
Runway separation in real-life is based on looking out the
windows at the aircraft in relation to other landmarks such as taxiways or the
runway ends. This does not happen in
Pro Controller or ASRC so work-arounds must be used. Watch the aircraft’s altitude readout compared to the field
elevation to determine when an aircraft has landed or is airborne. Compare aircraft positions to each other and
the runways on the radar map to determine when an aircraft is at the
appropriate points.
a)
Separate a departure from a preceding departure on the same
runway by ensuring it does not begin takeoff roll until the first aircraft is
airborne and past the runway end or turned to avert any conflict.
b)
Allow two minutes separation when any aircraft departs from
the same or parallel runways separated by less than 2500 feet behind a Heavy or
B757. This separation may not be waived
by the pilot.
c)
Allow three minutes separation when any aircraft departs
from an intersection behind a heavy jet or B757 or if it departs in the
opposite direction from the Heavy or B757 on the same runway. This separation may not be waived by the
pilot.
d)
Allow three minutes separation when a Light aircraft departs
from an intersection behind a Medium aircraft.
This separation is not required if the pilot has specifically requested
to waive the separation. A simple request for takeoff is not a request for a
waiver. Issue a wake turbulence cautionary advisory before clearing the Light
aircraft for takeoff.
e) Aircraft conducting multiple touch-and-go or stop-and-go operations in the VFR pattern are considered to be departing from an intersection. However, 3 minutes separation is not required unless ATC takes action to reduce the visual separation being applied by the pilot. For example, if you simply instruct the touch-and-go aircraft to “FOLLOW” the Heavy the 3 minutes are not required but if you tell it to “MAKE SHORT APPROACH” or “TURN BASE NOW” the 3 minutes are required.
f)
Do not taxi Light aircraft into Position and Hold behind a
departing Heavy or B757.
g)
Separate a departure from a preceding arrival on the same
runway by ensuring it does not begin takeoff roll until the arriving aircraft
is clear of the runway.
h)
Separate a departure from a preceding departure on an
intersecting runway by ensuring it does not begin takeoff roll until the first
departure has passed the runway intersection or is turning to avoid any
conflict.