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4. Clerances
4.1. On The Ground
4.1.1. Clearance
4.1.2. Pushback and Startup
4.1.3. Taxi
4.2. Airborne
4.2.1. Take-off and Cruise
4.2.2. Landing and Vacating the Runway
4.2.3. Ending a Flight
4.3. Clearance Limit
4.4. Conditional Clearance
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4.1 On the Ground [S]
Before
a pilot departs on a
flight, he/she has to make a number of Pre Flight preparations based
on,
amongst others, information about current weather, departure routes,
arrival
routes, waypoints en-route, cruising levels, weight and balance and
aircraft
conditions etc. When the pilot has received all information needed,
he/she will
create a flightplan (mandatory for IFR flights, but only required in
some cases for VFR flights) either from scratch or from a
pre stored flightplan. When the flightplan is complete it will be sent
to the
ATC and be processed into a flightstrip and distributed to suitable ATC
facilities. The flightstrip will contain data such as departure and
arrival
aerodromes, requested cruise level, route, type of aircraft, cruising
speed, if
the flight is to be flown under VFR or IFR regulations, alternate
arrival aerodrome and special remarks. This flightstrip makes the
substratum for the
controller’s actions. This means that it is vital that the
flightplan and
flightstrip is updated by ATC if any changes should occur during the
flight.
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4.1.1 Clearance [S]
The pilot will perform pre
startup checks and call clearance delivery for ATC-clearance, provided
clearance delivery is on-line. If Delivery is not on line, but Tower is on line
then the pilot will call Tower for clearance. If Tower is not on line but
Approach is on line then the clearance will be requested from Approach. I.e.
the pilot will always call the next position “above” the one ideally required. (NOTE: FSS stations do not provide
clearance service, as they man traffic ONLY above FL245). The pilot in
command will also go through loading sheets, fuel data, and boarding data
together with ground personal and flight crew.
The ATC-clearance is very
important, because
this clearance clears the aircraft from the aerodrome of departure to a specified clearance limit. This is
normally the destination aerodrome, but may in certain cases be a navaid or fix
(such as a FIR border). It also contains the route to follow after departure (a
SID, direct to a significant point, or a heading/track or radial to follow),
including altitude restrictions (although altitude restrictions may be included
in the SID, and thus not included in the spoken clearance).
These give the pilot a chance of pre-tuning
radios and prepare himself and the aircraft so the workload on climb out may be
limited. Due to the fact that the pilot is quite busy with the pre startup
procedures the controller shall make sure the pilot is ready to copy the ATC
clearance before reading it out. It is vital that the clearance is understood
correctly so everything in the clearance must be read back before proceeding.
Items marked with (*) below can be excluded in some instances.
The call for clearance from
the pilot should include:
1. Who (s)he is (Exair
131)
2. Where (s)he is (Somewhere
stand 36/Apron South)
3. What (s)he is* (Boeing
737)
4. Current ATIS designation, at some airports including QNH (Information
Mike, QNH 993)
5. What do s(he) want (Request
startup and clearance
to Someplace airport)
The clearance from ATC should
include:
1. Clearance limit (Someplace
airport)
2. Departure route (Can be a SID/Significant Point/Heading
/Track/ Radial) (VORING
2 Golf departure)
3. Route* (Upper November 850)
4. Initial altitude/level (5000
feet, not needed if this is specified in the SID)
5. Transponder code (Squawk) (Squawk
7351)
NOTE1: A SID normally includes the published initial
altitude and climb constrains as such
this information is not usually necessary.
However it is often included in the clearances.
NOTE2:
mainly in the USA the clearance also includes the departure frequency, as such a 6th
element in the clearance would
be:
6. Departure frequency (After departure contact 125.35)
This is also referred to as CRAFT: C (learance): cleared to destination, R(oute): via SID dep A(ltitude): climb initially 5000' F(req): after dep contact xxx.xx T(ransponder): squawk 7134.
Additional
information from the controller:
1.
Departure runway* (Runway 19 – not given if it is included in ATIS)
2.
Wind* (250 degrees 5 knots – not given where ATIS is
available)
3.
QNH* (QNH 993
– not given if the pilot has already reported the correct QNH)
4. Temperature* (15 – given to
turbine engine aircraft where no ATIS is available)
5. Runway Visual Range* (RVR) for the departure runway (given when reported, where no ATIS is
available)
6. Runway conditions (braking
action and contamination)* (Braking action good, runway wet – given when
reported, where no ATIS is available)
Note: At
many smaller airports, where the ATC clearance is transmitted to the pilot by
TWR or AFIS, the controller or AFIS officer must obtain the clearance by
calling the ACC or APP unit, when the pilot requests start-up. Therefore, at
these airports, TWR/AFIS will not be able to transmit the clearance to the
pilot on the initial call. Depending on how long time it takes to retrieve the
clearance, it will be issued before or during taxi. Naturally, it must be given
before take-off.
If you have the time, it
might be good to write down the clearance on a piece of paper before you feel
that you can give a clearance fluently.
An alias sentence is very
valuable in order to issue ATC clearances
If the pilot calls you before
you have been able to make all necessary preparations to give the clearance,
you can ask the pilot to wait. It is however important to stress that any call
from a pilot should be acknowledged as soon as possible, even though you can’t
give the clearance straight away. In those instances you can often give some
information, such as the QNH and active runway.
XXX131
“Somewhere Clearance delivery, Exair 131, Boeing 737, Stand 36
with information Echo. Request start-up and clearance to
Someplace.”
DEL “Exair 131, Start-up approved, QNH 993. Stand by for clearance.
XXX131 “Start-up approved, QNH 993, Exair 131.
A rule
of thumb is that you shouldn’t read the clearance to the pilot if he hasn’t
asked for it. If he only asks for push-back, that’s what you should give him
initially. The actual clearance would then follow in a separate transmission. If
you have asked the pilot to wait until you have reviewed his flightplan and
made necessary preparations to give him the clearance, you should ask him if he
is ready to copy the clearance before you read it to him. In other words, avoid issuing the clearance
unless you are certain that the pilot is ready to copy.
DEL "Exair 131, (are you) ready to copy clearance?"
XXX131 "Ready to copy / Go ahead, Exair 131"
DEL
"Exair 131, clearance to Someplace
via VORING 2 Golf departure, 5000 ft, Squawk
7351”
XXX131
"Clearance to Someplace via VORING 2 Golf departure, 5000 ft, Squawking 7351, Exair 131”
DEL “Exair 131, read back correct, Contact Ground on 121.95 for pushback”
XXX131 “Ground on 121.95, Exair 131, Bye”
The pilot should read back
all elements in the clearance to confirm that he has copied them right. As
controller it is hence very important to listen to the read back actively. If
the read back is correct, this should be acknowledged and if not, the mistakes
should be corrected. If for example the squawk is read back wrongly, you don’t
have to read the whole clearance one more time. It is enough to correct only
the parts that were misunderstood.
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4.1.2. Push-back and Start Up [S]
When boarding is completed and all pre-startup procedures are done, the
pilot will call for either pushback or startup or both. (whether pushback is required naturally depends on the
parking position). At certain airports, apron control (callsign “Apron”) is
available to handle pushback, start-up and aircraft movements on the aprons. At
other airports, Ground approves pushback and start-up, but the actual
manoeuvres are supervised by ground mechanics. Before you give push-back approval, make sure that the immediate area
around the aircraft is free of any conflicting vehicles or other aircraft. You
can also tell the pilot to push-back at own discretion, in which case he has to
look out for traffic on his own. It is however better to give clear and precise
instructions in order to minimize the risk of crashes.
XXX131 “Somewhere Ground, Exair131. Stand 36, request pushback”
GND “Exair 131, pushback approved”
XXX131 “Pushback approved, Exair 131”
XXX124 “Somewhere Ground, Exair 124, Stand 34, request pushback”
GND
“Exair 124, hold position, company MD11 pushing from Stand 36”
or
GND
“Exair 124, when free of company MD11 pushing from Stand 36, push back approved”
Sometimes ATC may have to delay the start up approval due to congestion
on the ground or due to saturation in the area.
GND “ExAir123, Expect Start Up at 15.15Z”
Or
GND
“ExAir123 Expect Departure time at 15.15Z Start Up
At your discretion"
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4.1.3. Taxi [S]
To allow the
ground controller to rely on and use traffic flows on the taxi ways,
the pilot should be ready to taxi before requesting taxi clearance. As
soon as the taxi clearance is received, the pilot is expected to carry
out the taxi instructions as soon as possible to obtain best traffic
flow.
The
taxi-ways are many and varied and their structure is complex, especially at
bigger airports. Taxi-ways are often one-way only in order to avoid situations
with two aircraft converging nose to nose – aircraft have no reverse gear. The
ultimate embarrassment for a Ground controller occurs when two aircraft taxi on
the same taxiway but head on. In these hopefully rare cases the rule of thumb
is that each aircraft on the ground should turn to the right to allow sufficient
space between the aircraft, prior to continue with taxiing
Taxi-ways can be one-way in one direction (say south) when one
runway-configuration is in use, and one-way the other way (say north) when
another runway-configuration is in use. It is good to have a chart over the published
standard taxi-way routes at hand when you are controlling a bigger airport. All
Taxiways that you want an aircraft to follow to the Runway or to a gate should
be specified by the controller.
If traffic is dense and many planes are taxiing to and from the gates
and runway, you have to think one step ahead. You might have given
instructions to pilots to hold at certain intersections to let other
aircraft pass, or instruct pilots to follow preceding traffic to
maintain a safe and smooth flow.
XXX131 “Exair 131 request Taxi”
GND
“Exair 131, behind company DC 9
passing from left to right on Yankee, taxi to holding
point runway
19 Right”
XXX131 “Behind company DC 9, taxi to holding point runway 19 Right, Exair 131”
NOTE: In 2005
ICAO as part of a comprehensive effort to improve runway safety, changed the
phraseology “TAXI TO HOLDING POSITION” into “TAXI TO HOLDING POINT” in the PANS-ATM,
in order to avoid confusion with the non-ICAO phraseology “TAXI INTO POSITION
AND HOLD” which continues to be used by some worldwide. As the “holding point”
referred to in the revised phraseology is synonymous with “runway holding
position” Therefore;
when used in radiotelephony phraseology, “runway holding point” refers to
“runway holding position”
Whilst Ground is primarily responsible for
all traffic movements on the ground and would normally hand over to Tower when
the aircraft is holding short of a Runway, an exception occurs at many airports
having taxi routes that cross a Runway (even if not active) as in these cases
Ground hands over responsibility to Tower at the holding point of the runway to
be crossed and Tower from that moment on continues issuing Taxi instructions,
except when Ground and Tower coordinate the ground and taxi movement between
them in which cases usually Ground will have received prior approval from Tower
authorizing Ground to issue Runway crossing instructions to any aircraft on the
ground.
There are different manners in which Ground or Tower as the case may be
can issue Taxi Instructions:
GND “ExAir23 Taxi Via Y and B to holding point B3 runway 22R”
Or
GND “ExAir123 Taxi to Holding Point F1 runway 18”
Or
GND “ExAir123 line up rnway 12 via backtrack, report ready for departure”
Or
GND “ExAir123 Turn (First/Second) taxiway (Left/Right)”
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4.2 Airborne [S]
4.2.1. Take-off and Cruise [S]
When the aircraft has reached the holding point and the pilot is ready
for departure, it is time to line up. An aircraft is lined up when it is
standing on the runway centre-line with the nose pointing in the direction of
the active runway.
It is allowed to instruct a pilot to line up even though the runway
isn’t clear – i.e. preceding traffic hasn’t vacated the runway.
The only time the word “take-off” is used is when the
aircraft is cleared for “take-off”. in all other transmissions, the word
“departure” should be used. This is very important since a
misunderstanding at this stage can be very dangerous.
XXX131: “Tower, Exair 131”
TWR:
“Exair131, You are no 2 for
departure, in sequence behind the SAAB 340, line up and wait rwy 19
right”
XXX131: “In sequence behind the SAAB 340, line up and wait rwy 19 Right, Exair 131”
The instruction “line up in sequence” means that when the
aircraft in front of XXX131 has begun his take-off roll down the
runway, XXX131 can line up and wait behind him with no further ATC
instructions.
TWR: “Exair 131, you are no 2 for departure”
XXX1465: “Tower, Exair 1465 is ready for departure”
Next follows the take-off clearance.The
runway designation always has to be included in the take off clearance. Also
include the present wind if it is significantly different from the wind
reported in the ATIS or previously given to the pilot.
TWR:
“Exair 131, rwy 19 Right cleared for take
off; wind 210 degrees 8 knots.”
XXX131: “Rwy 19 Right, cleared for take off, Exair 131”
Reminder: Wind direction and speed is weather information from the ATC
and is not required to read back. (QNH is the exception) As QNH is
required information for procedures (TA/TL) it’s a directive and
not an information. That said, QNH, being a directive, needs the
readback. All other informations which does not imply directives (as
weather information or ANY other information) do not need readback
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4.2.2. Landing and Vacating the Runway [S]
Before you can clear an aircraft to land, you have to make sure the
runway is free from all other traffic and that no other aircraft is
ahead on final. If this is the case, you’ll have to instruct the
pilot to "continue approach" until you are able to give him clearance to
land.
Remember that speed is the best way of separating aircraft on final,
but that speed restrictions usually are waived when the aircraft passes
over the outer marker, as specified in the AIP for the airport.
If the phrase “Callsign only” is included in handover, it
means that the pilot should check in to the new controller with his
callsign only. No need to make any position report to ATC.
APP: “Exair 4321, contact Tower 118.5, callsign only”
XXX4321: “Tower 118.5, with callsign only, Exair 4321”
XXX4321: “Somewhere Tower, Exair 4321”
TWR: “Exair 4321, continue approach, you are no 2, wind 280 degrees 4 knots”
XXX4321: “Continue approach, number 2, Exair 4321”
TWR: “Exair 4321, Runway 26, cleared to land
XXX4321: “Runway 26, cleared to land, Exair 4321”
Note: If there is no big changes in wind speed or direction this
information only have to be told by the controller one time and
therefore be left out the in the last “cleared to land”
phrase in this example.
The word “vacated” is used when we mean that an aircraft
has left the runway or “vacated runway”. The word "clear"
or "cleared" should never be used in this context in order to avoid
confusion.
XXX4321: “Exair 4321 vacated runway 26”
TWR: “Exair 4321, roger taxi to stand 36”
XXX4321: “Taxi to stand 36, Exair 4321”
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4.2.3. Ending the Flight [S]
When
the aircraft has vacated the runway it is time to taxi to the gate or
apron. These instructions are covered in the section above (3.1.3). Since aircraft
are very different in shape and size, parking stands and gates are designed for
different aircraft types and sizes. There may also be different terminals for
different airlines and different aprons for different types of traffic (general
aviation, cargo, military etc) Study the information for your airport to know
where different aircraft should be parked
Many pilots ask permission to end the flight at gate, or to shut the
engine.
XXX4321: “At the gate, request closing Flight Plan and leave frequency”
TWR: “Roger, thanks for Flying to "Somewhere" Have a nice evening. Goodbye”
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4.3. Clearance Limits [S]
We
have mentioned the words Clearance Limit in various contexts above but
for good orders sake, in order that both ATC and Pilots know what these
words mean
The
Clearance Limit mainly concern pilots and what actions they are expected to
take in the event of communication failure. This is of course especially important in busy periods like a fly-in
Clearance Limit is the point to which an
aircraft has been cleared by a particular ATC. The aircraft is at any time
allowed to proceed to that particular point, but not past it.
The Clearance Limit differs, depending on the
ATC Position issuing the clearance…
Clearance
Limit issued by Delivery:
ExAir123, cleared as filed to LFPG
via flight plan route, sq 1122, intl FL70, Rwy 36C
In the above example, the Clearance Limit is
LFPG and forms part of the general clearance.
Clearance
Limit issued by Ground
ExAir123, taxi via Y and A to 22R,
hold short of crossing 12/30
In the above example, the Clearance Limit is
the Holding Point short of crossing 12/30 where the aircraft HAS to stop and
await further instructions.
Clearance
Limit issued by Tower
ExAir123, taxi via Y to Rwy 22R
hold short at A3
In the above example the Clearance Limit is
the holding point A3, short of runway 22R, the aircraft HAS to stop at A3 and
await further instructions.
Or
ExAir123, cleared for take off on
SORGA1C sid, winds 220 at 20
In
the above example the Clearance Limit is
the prescribed Max Altitude relevant to the SID being flown and the
Limit (in event of a communication failure) is
SORGA, the aircraft will climb to and mantain this altitude until
cleared to climb further and will need to enter a hold over SORGA is no
further instructions
are given.
Clearance
Limit issued by ACC
ExAir123, Proceed EEL reach EEL at FL110
In the above example the Clearance Limit is
EEL, the aircraft has been cleared to EEL vor at FL110, if the aircraft does
not receive further instructions before reaching EEL, the aircraft HAS to enter
a standard hold until receiving further instructions.
Most pilots like to receive a short cut from
ATC if possible, and this usually is done during the cruise by the ACC. The
thing to bear in mind here is that you should never clear a pilot to a ”direct”
navaid or point which falls outside of your AOC.
If
however ACC instructs the pilot to proceed ”direct EEL” as a short cut the the pilot
is expected to continue according to the flight plan route when reaching EEL
ExAir123, Cleared Direct EEL
Or
ExAir123, Cleared inbound Arlanda via
TROSA3M arrival Runway 26
In this example the Clearance is the end of
the STAR in this case it would be at TEB (which is the IAF). The pilot can
follow the arrival route as pescribed and over TEB unless the approach
controller has recleared the aircraft further would enter the hold.
In Conclusion, unless a follow up clearance
is given or a handoff to a new ATC is done, an
aircraft will HOLD at the clearance limit. Aircraft’s on the ground will
stop and hold for instructions, whilst aircraft’s in the air will enter
standard Hold patterns.
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4.4. Conditional Clearance [S+]
Conditional clearances, in
which the controller issues an instruction that becomes valid after another
event has occurred, have been identified as a contributory factor in
a significant number of incidents, particularly in relation to clearances
issued to aircraft in the vicinity of a runway.
It is essential that pilots
fully understand the clearance that they have been given and the event that
must occur before the clearance is valid. If a pilot is in any doubt whether he
or she is cleared to enter or cross a runway, either when the clearance is issued
or later, confirmation of the clearance must be sought from ATC.
Common causes of confusion
are instructions that relate to a particular aircraft type when there are
several aircraft of that type (or a number of aircraft that are similar in appearance,
for example A319, A320 and A321) in the area. Similar confusion can result when
an instruction relates to an aircraft operated by a specific company when there
are several aircraft in that company’s livery in the area (this can be a
particular problem at an operator’s home base).
Conditional clearances will
take the form of the aircraft callsign, the event that must occur before the
clearance is valid (including the identification of vehicle or other aircraft
involved), followed by the clearance/instruction.
ExAir123, After departing
A320, line up Runway 01 Right.
Or
ExAir123, Behind the
landing B757 on short final, line up behind, Runway 01 Right
If there is any doubt about
the identification of the aircraft that is the subject of the condition, pilots
must obtain clarification from ATC.
Conditional clearances may
not be used for movements affecting the active runways except when the aircraft
or vehicles concerned are seen by both the controller and pilot. Conditional
clearances will normally relate to one movement only and, in the case of
landing traffic, this will be the first aircraft on approach.
Sometimes ATC may consider it necessary for an aircraft to
take-off without any delay. Therefore, when given the instruction. ”cleared for
immediate take-off”, the pilot is expected to act as follows:
- At the holding point: Taxi
immediately on to the runway and commence the take off roll without stopping
the aircraft.
- If already lined up on the runway:
to take off without delay.
Exair123, Cleared for immediate take-off Runway 26
Left
Or due to unexpected traffic, or a departing traffic taking longer to
take off than anticipated, it is sometimes necessary to cancel the take off
clearance or quickly free the runway for landing traffic.
Exair123, Take-off immediately or vacate the runway
Or
Exair123, Take-off immediately or hold at the holding
point
Sometimes ATC may need to cancel a take-off clearance even after the
pilot has started the take-off roll. In these cases ATC will need to repeat the
instructions and ensure the pilot reads-back.
Exair123, Hold position, cancel take-off. I say again,
cancel take-off, acknowledge.
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