VFR flights may be either cancelled or changed to IFR flights. VFR flights can be prohibited to enter the controlled airspace if meteorological conditions are worse than 5000m visibility and 450m cloud base and there are other traffic operating either IMC or VMC (low ceiling or overcast conditions)
So, if there is a possibility that flight under VMC may become impracticable, an IFR flight shall be provided with alternative instructions to be complied with in the event that flight in VMC cannot be maintained for the term of the clearance.
If a pilot has the intention to change the flight rules, he has to inform the controller about his decision and the controller shall change flight plan (if available or necessary) and inform the other ATC units en-route about the changes.
b) What is radiotelephony phraseology?
Radiotelephony English is the language used in radiotelephony communications. It includes but must not be limited to ICAO phraseology and can require the use of "general" English at times Plain language refers most often to what we are calling here radiotelephony English but also may require "general" English.
ICAO phraseology. The standardized words and phrases approved for radiotelephony communications by ICAO have been developed over years and represent a very narrow, specialized and rigid subset of language.
27. a) Procedure of controllers actions in case there are obstructions on the RW.
- If an aircraft approaches the aerodrome and there are some obstructions on the RW, the controller informs a pilot to make a Go around procedure and gives a reason (e.g. RW is blocked, water patches on the RW, etc), e.g.
KLM 127. Go around. RW blocked. Climb to altitude 2000ft.
Contact approach 118.7
- If a pilot departs and after receiving a take-off clearance some obstructions have appeared on the RW, the controller gives instructions to hold position or to cancel take-off.
If an aircraft has started taxiing and there are some obstructions on the RW, the controller gives an instruction to an aircraft to stop immediately (saying twice) and informs a supervisor about it.
If the speed of an aircraft is too high while taxiing and it starts stopping, it can use emergency braking. In this case a pilot can start a departure procedure again or return to stand for aircraft inspection.
In the event the aerodrome controller observes, after a take-off or landing clearance has been issued, any obstruction on the runway, such as runway incursion by an aircraft or vehicle, or animals or flocks of birds on the runway, appropriate action shall be taken:
1. in all cases inform the aircraft concerned of the obstruction and its location on the runway;
2. cancel the take-off clearance for an aircraft which has not started to roll;
3. instruct a landing aircraft to go around,
b) Why is it important to have sophisticated equipment at the working place?
There should be mentioned:
- more precise and detailed data concerning traffic,
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- increased controller efficiency,
- reduced voice radio channel congestion, and
- fewer controller/pilot communication errors,
- datalinks present controllers and pilots with a new, faster means of sharing pertinent information,
- increased airport and airway capacity,
- increased efficiency in using airspace.
28. a) Procedure of controllers actions when directing aircraft to the alternate aerodrome.
If the aerodrome cannot receive the aircraft due:
- blocked runway,
- bad runway conditions (water 10mm or more, slash 12mm or more, snow over 50mm, braking coefficient less than 0,3, braking action poor),
- weather below minima,
- low RVR or cloud base,
- landing system failure
and the flight crew has made decision to fly to the alternative aerodrome, the controller shall inform the supervisor about diverting the aircraft to an alternative.
The aircraft is cleared to proceed to the alternative if the length and the operational conditions on the alternative aerodrome are applicable for the aircraft and it handles international flights (for the aircraft carrying out an international flight).
If airspace conditions allow to follow direct to the alternative aerodrome, the aircraft shall be cleared to fly to new destination via the shortest route. If airspace conditions do not allow to follow direct to the alternative the aircraft shall be cleared to fly to a new destination and the controller shall instruct the pilot to fly via the cleared route.
Directing the aircraft to the alternative aerodrome the controller shall:
1. specify the operational conditions, actual and forecast weather conditions at the alternative aerodrome and advise this information to the pilot before the aircraft leaves the zone of responsibility,
2. inform the anti-aircraft defense forces unit about the flight directed to the aerodrome of changed destination,
3. inform the adjacent ATC unit about diverting the aircraft to the alternative aerodrome (if the aerodrome is located within its FIR) or inform the aerodrome ATC unit about diverting the aircraft to the alternative aerodrome,
4. make relevant changes to the flight plan,
5. transfer the control under the aircraft to the adjacent ATC unit,
6. obtain the information concerning the aircraft landing on the alternative aerodrome.
b) TCAS. What is it ?
A traffic collision avoidance system or traffic alert and collision avoidance system (both abbreviated as TCAS) is an aircraft collision avoidance system designed to reduce the incidence of mid-air collisions between aircraft. It monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder, independent of air traffic control, and warns pilots of the presence of other transponder-equipped aircraft which may present a threat of mid-air collision (MAC). It is a type of airborne collision avoidance system mandated by the International Civil Aviation Organization to be fitted to all aircraft with a maximum take-off mass (MTOM) of over 5700 kg (12,586 lbs) or authorized to carry more than 19 passengers.
Official definition from PANS-ATM (Nov 2007): ACAS / TCAS is an aircraft system based on secondary surveillance radar (SSR) transponder signals which operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders.
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In modern glass cockpit aircraft, the TCAS display may be integrated in the Navigation Display (ND); in older glass cockpit aircraft and those with mechanical instrumentation, such an integrated TCAS display may replace the mechanical Vertical Speed Indicator (which indicates the rate with which the aircraft is descending or climbing).
29. a) Peculiarities of aerodrome traffic service under VMC conditions.
VMC conditions: visibility 5000m and more, cloud base 450m and more.
1) IFR and VFR flights can be performed at the same time (if weather conditions are lower, so IFR and VFR flights can be performed but on opposites sides of the CTR).
2) The controller has to inform all aircraft flying VFR about traffic (IFR and VFR flights). A pilot will be able to maintain own separation, e.g.
KLM 127. Traffic 1 oclock, 50 km, opposite direction, FL 240, TU 134.
3) The controller informs about the highest altitude which is available, e.g.
KLM 127. Enter controlled area not above 3 000ft.
4) An aerodrome traffic circuit is provided for all aircraft flying under VMC conditions.
b) Runway incursion. What is it ?
RUNWAY INCURSION is an incident where an aircraft enters a runway without an air traffic control clearance. It may involve the incorrect presence of a vehicle or a person on the protected area of a surface designated for aircraft landing and take-off.
This may include:
two aircraft coming head-to head
an aircraft colliding with another one
an aircraft colliding with a ground vehicle
an aircraft entering an active RW
This may cause:
an aircraft damage to the aircraft, either minor or severe
forced to go around
an official investigation of accidents
A) Priority for landing.
If an aircraft enters an aerodrome traffic circuit without proper authorization, it shall be permitted to land if its actions indicate that it so desires. If circumstances warrant, aircraft which are in contact with the controller may be instructed by the controller to give way so as to remove as soon as possible the hazard introduced by such unauthorized operation. Permission to land shall not be withheld in any case.
In cases of necessary it may be necessary, in the interest of safety, for an aircraft to enter a traffic circuit and effect a landing without proper authorization. Controllers shall recognize the possibilities of emergency action and provide all necessary assistance.
The other aircraft may be instructed to give it way to remove the hazard.
Priority shall be given to:
1) an aircraft in cases of engine failure, shortage of fuel and others affecting the safe operation of the aircraft;
2) hospital aircraft and aircraft carrying any sick or seriously injured persons requiring urgent medical assistance;
3) aircraft engaged in search and rescue operations;
4) other aircraft determined by the appropriate authorities.
b) What is the role of stress in a controller`s job?
Air traffic controllers (ATCs) are generally considered one of the working groups having to deal with a highly demanding job.
I In fact, it entails a complex set of tasks requiring very high levels of knowledge and
expertise, as well as the practical application of specific skills pertaining to cognitive domains(e.g. spatial perception, information processing, logic reasoning, decision making), communicative aspects and human relations.
To have an idea of its complexity, it is sufficient to mention that, according to a job
analysis of en-route controllers carried out by a group of American researchers,1 six main activities can be identified (i.e. situation monitoring, resolving aircraft conflicts, managing air traffic sequences, routing or planning flights, assessing weather impact, managing sector/position resources), which include 46 sub-activities and 348 distinct tasks. For example, the relevant cognitive/sensory attributes required for high performance levels at radar workstations are spatial scanning, movement detection, image and pattern recognition, prioritizing, visual and verbal filtering, coding and decoding, inductive and deductive reasoning, short- and long-term memory, and mathematic and probabilistic reasoning.
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Three common stresses as an air traffic controller are: the complexity of traffic, working long shifts with no break, and dealing with complex traffic during adverse weather.
Many things can affect the complexity of the traffic a controller has to deal with. One or two aircraft inbound or outbound to the same location is usually not a problem. Controllers really earn their money when multiple aircraft are conducting approaches on intersecting runways simultaneously while other aircraft are departing the same runways. For instance, there are times air traffic controllers will be communicating with ten or more aircraft all within five miles of each other, and many on converging courses. Some of the busier airports handle over one hundred operations an hour. To illustrate, that is almost two takeoffs or landings every minute. The density of traffic can continue uninterrupted for hours. This can be very stressful for controllers that work by themselves, which is common in Federal Contract Towers. In some instances, air traffic controllers are handling a variety of tasks at the same time such as: combining all positions in the tower, talking with aircraft in the sky, on the ground, and coordinating with up to three facilities at once.
Most Federal Contract Towers provide for only one air traffic controller to be working at a time. This can cause extra strains on the individual controller over an eight hour shift. There have been times where the air traffic has been so busy for extended periods of time that the controller could not take bathroom breaks. This added stress can initiate errors that could be prevented if adequate breaks were available. In addition, statistics have also shown that the level of awareness among air traffic controllers decreases sufficiently after two continuous hours on position. Eating can be another problem for controllers that work alone. Specifically, some facilities do not even provide refrigerators or other places to store food during a shift. This can make the selection of food available very limited and cause performance to decrease in controller duties.
A busy day at an air traffic control facility is one thing. When weather moves into the area it creates even bigger problems. In fact, a significant weather system is similar to a giant wall as far as pilots and controllers are concerned. For this reason, the effects of an aircraft flying into a storm system can be catastrophic and controllers monitor and re-route traffic so hazardous weather is avoided at all costs. Also, storm systems can appear on radar with very short notice and controllers must make quick decisions to avoid having the aircraft fly into the weather or into the airspace of another plane. Sometimes air traffic controllers receive radio calls from pilots that have encountered hazardous weather without notice. The pilot is relying on the controller to find the quickest and safest way out of the storm.
It takes a certain kind of individual to deal with the amount of stress an air traffic controller has to endure during a routine shift. As a result, the Federal Aviation Administration requires air traffic controllers to retire by the age of 56. A stressful day for an average person is just another day on the job for a controller. Air traffic controllers have been around for sixty years and with every day that passes more and more passengers rely on the valuable service they provide. In conclusion, the United States air traffic control system is and will continue to be the most complex yet safe and efficient air traffic control system in the world.
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Main sources of stress for ATCs
Demand:
_ number of aircraft under control
_ peak traffic hours
_ extraneous traffic
_ unforeseeable events
Operating procedures:
_ time pressure
_ having to bend the rules
_ feeling of loss of control
_ fear of consequences of errors
Working times:
_ unbroken duty periods
_ shift and night work
Working tools:
_ limitations and reliability of equipment
_ VDT, R/T and telephone quality
_ equipment layout
Work environment:
lighting, optical reflections
_ noise/distracters
_ microclimate
_ bad posture
_ rest and canteen facilities
Work organization:
_ role ambiguity
_ relations with supervisors and colleagues
_ lack of control over work process
_ salary
_ public opinion
