Traffic indicators investigation

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Traffic indicators investigation

1. Theoretical information

flight airspace flow

Control Zone - a controlled airspace extending upwards from the surface of the earth to a specified upper limit, control and ATS of which is provided by appropriate ATS unit.

Terminal Control Area - a control area normally established at the confluence of ATS routes in the vicinity of one or more major aerodromes.

The main purpose of TMAs is the provision of safe flights for aircraft leaving system of ATS routes for landing at given airdrome or taking-off from the airdrome and entering the ATS routes system.

The required TMA dimensions are determined by provision of descend and landing approach conditions via the shortest way (straight-in approach) for aircraft, which passed entrance corridor at the upper established flight level for TMA till the transition level and moment of reaching CTR borders, taking into account aircraft performance characteristics for aircraft operating at this airdrome.

Straight-in approach pattern is considered like the most economical and provides the TMA capacity almost corresponding to norm, but requires greater TMA dimensions.

Calculation of TMA radius is performed according to formulas:

R_ТМА д_max + S_late + S_des + S_CTR/2_;

S_late = MC* (t_wl + t_react);

S_des = MCS*(H_ent - H_GPE)/v_y,where:

д_max - error of determination by the crew of moment of flight over outer marker (the border of TMA);

S_late - distance, of flight of aircraft from the moment of flight of outer marker to the moment of beginning of descent;

S_des - distance of flight of the aircraft at the descending from Н_ent to Н_GPE;

S_CTR - size of CTR from side of approach;

MC - true air speed of flight of the aircraft at the entrance in aerodrome zone;

t_wl - average time of occupancy of ATCo by a radio exchange with other crew;

t_react - ATS system delay;

Н_ent - altitude (flight level) of entrance in aerodrome zone;

Н_GPE - glide slope entrance height;

MCS - forward speed of an aircraft at the descending from Н_ВХ to Н_ВГ;

V_y - rate of descent of an aircraft from Н_ent to Н_GPE

ATS route - certain route assigned for directing traffic flow with the aim of ATS provision. This term is used for airways, controlled or uncontrolled routes, conditional routes, arrival and departure routes etc.

Airway - an airspace corridor with limited height and width and equipped with ground based navigation aids.

Air corridor - connection between ATS routes and control zone.

Types of air corridors:

· arrival (approach) to the aerodrome area;

· departure from the aerodrome area;

· mixed (arrival, departure).

Air Traffic - all aircraft at flight or moving in aerodrome manoeuvring zone.

Separation - intervals between aircraft, levels or tracks.

Flight Level - a surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals.

Note 1. A pressure type altimeter calibrated in accordance with the standard atmosphere:

1. when set to a QNH altimeter setting, will indicate altitude;

2. when set to a QFE altimeter setting, will indicate height above the QFE reference datum;

3. when set to a pressure 1 013.2 hPa, may be used to indicate flight levels.

Note 2. The terms «height» and «altitude», used in Note 1 above, indicate altimetric rather than geometric heights and altitudes.

When we set QFE pressure it will show us a relative height over the aabutment point of QFE;

When we set pressure 760mm (1013,2 Hpa) it may be used for indication of flight levels;

Air traffic management - is a complex of ground and onboard facilities, that are necessary for provision of safety of flight during all its steps.

Air traffic service - flight information service, consultative service, emergency service, air traffic control service (approach air traffic control service, terminal air traffic control service, area air traffic control service)

Intensity of flight - amount of aircraft actually taken to a control.

- amount of aircraft;

T - average time of flight of aircraft in air traffic area;

Density of air traffic - amount of aircraft, that are in 1 unit of volume of air traffic control zone.

; ;

Load of zone - amount of aircraft that are under control in the limits of given zone simultaneously.

Coefficient of load of zone:

- throughput.

Throughput of air traffic zone - amount of aircraft that can be serviced by air traffic control units of this zone in 1 unit of time with adherence of normative indications of safety of flights.

Throughput of air traffic controller - amount of aircraft that can be under control of air traffic controller in 1 unit of time taking into account direct procedures of control simultaneously.

Work load of air traffic controller - time needed to perform necessary technological procedures of air traffic control.

Factors that influence on commitment:

- intensity of flights;

- density of flights;

- structure of zone (size, amount of routes, amount of points of intersection of routes)

- characteristics of aircraft flows (directions of flows, relations of types of aircraft in flows) equipment of work place

- air traffic management (features of work technology, amount of air traffic controllers in 1 zone, character of restrictions in airspace)

- level of air traffic controller

- work place management

- regim of work and rest

- character of work place environment

- psychological and psycho-physical characteristics of air traffic controller

Coefficient of work load of air traffic controller is expressed by relation of time spent by air traffic controller to perform technological procedures and total resource of time.

- is obtained only when we can calculate the time of operations. Coefficient of work load of air traffic controller has to be placed in the limits ftom 0.2 to 0.85, normative coefficient is 0.55. Relation between commitment coefficient and main characteristics of flow of aircraft is expressed by following equation:

- time spent on voice communication during aircraft aperations (ex.: climbing, descending)

- time spent on giving of instructions to change FL, direction of flight, conflict situation, conditions of flight.

- time spent on information exchange between neighbour controllers, air traffic coordination, work with strips and equipment of air traffic control system.

2. Calculation of TMA sizes

3. Construction of zone and flight plan

4. Modeling of zone in experimental program «Potok»

The experimental controlled airspace «Ivlieva» at program «Potok» looks like:

Fig.5.1 The look of CTA «Ivlieva» in program «POTOK»

After the experiment has been made, 1 conflict situation occurred within the limits of CTA (fig.5.2).

Fig.5.2 The conflict situation

The conflict situation has occurred in TMA1 zone on the segment БЕ-ДО. The horizontal distance between ACFT at the moment of conflict was about 10.5 km. According to nowadays standards, it is not the conflict because in TMA zone we use the 5NM (9.3 km) separation minima. But as the program is old, the separation minimum in its database equals 30 km. So, the following measures can be used to avoid such conflict:

1. Order one ACFT to stop climb and another to stop descent until the creation of longitudinal separation;

2. To create lateral interval by means of turning ACFT with less speed left or right on 30 degrees. After the creation of lateral interval to allow further climb or descend, and after creation of VSM, return ACFT with less speed to the rout.

5. Analysis of main flow direction of modeled airspace

Main flow direction:

Fig.6.1 Direction of traffic flow

- 10% of flow has direction 0°

- 2.5% of flow has direction 30°

- 22.5% of flow has direction 60°

- 5% of flow has direction 90°

- 2.5% of flow has direction 120°

- 12.5% of flow has direction 150°

- 7.5% of flow has direction 180°

- 0% of flow has direction 210°

- 10% of flow has direction 240°

- 10% of flow has direction 270°

- 10% of flow has direction 300°

- 7.5% of flow has direction 330°

According to the flight levels:

- FL 430 has main flow direction 90°

- FL 400 has main flow direction which is divided 50/50 between 240° and 0°

- FL 390 has main flow direction 60°

- FL 380 has main flow direction 240°

- FL 370 has main flow direction 90°

- FL 360 has main flow direction 0°

- FL 350 has main flow direction 150°

- FL 330 has main flow direction 180°

- FL 320 has main flow direction 300°

- FL 270 has main flow direction 150°

- FL 260 has main flow direction 270°

- FL 240 has main flow direction which is divided 50/50 between 60° and 240°

- FL 220 has main flow direction 0°

- FL 210 has main flow direction 330°

- FL 200 has main flow direction 60°

- FL 160 has main flow direction 300°

- FL 100 has main flow direction 60°

- FL 90 has main flow direction 150°

6. Determination of density and intensity of the flow

I have determined density and intensity for 10 minutes intervals and constructed a histogram, which contains information about density and intensity of traffic flow for every 10 minutes of research (fig.7.1).

Fig.7.1 Density and intensity for 10 minutes intervals

L route = 8500 km

Density at intervals:

- 00-10:

- 11-20:

- 21-30:

- 31-40:

- 41-50:

- 51-60:

- 61-70:

- 71-80:

- 81-90:

- 91-100:

- 101-110:

- 111-120:

- 121-130:

The workload coefficient calculated in «POTOK» is shown on figure 7.2.

Fig.7.2 The ATCO workload

On the figure 7.2 there is the ATCO workload coefficient for every 10 minutes. According to this diagram:

- Average ATCO workload = 0.67;

- Min ATCO workload = 0.090;

- Max ATCO workload = 0.895.

After the analysis of results obtained above I can make the conclusion that the ATCO is overloaded because there is a period of time when the workload coefficient is greater than maximum acceptable. That's why I decided to divide CTA «Ivlieva» on two parts in horizontal plane to decrease the workload of a controller.

7. Construction of zone «Ivlieva_North», flight plan and ATCO workload

Fig.8.1 CTA «Ivlieva_North» on scheme

Table 8.1 Flight plan for CTA «Ivlieva_North»

The division of CTA lead to the following:

Fig.8.2 The CTA «Ivlieva_North» in program «POTOK»

Fig.8.3 The ATCO workload in CTA «Ivlieva_North»

Thus, according to the obtained results we see that the ATCO workload fell down and remained acceptable during the all period.

8. Construction of zone «Ivlieva_North», flight plan and ATCO workload

Fig. 9.1 CTA «Ivlieva_South» on scheme

Table 9.1 Flight plan for CTA «Ivlieva_South»

CTA «Ivlieva_South» has a following look:

Fig.9.2 The look of CTA «Ivlieva_South» in program «POTOK»

Fig.9.3 The ATCO workload in the CTA «Ivlieva_South»

We see that ATCO workload fell down and became normal during the all period of time.

Conclusion

After the performance of term work I analyzed obtained results and made the conclusion that the ATCO workload depends on such traffic indicators as density, intensity, etc. That's why suitable planning of airspace structure leads to declining of workload which reduces the possibility of conflicts and conflict situations appearance.

References

1. Terms of aircraft operations and air traffic services in the classified airspace of Ukraine: Order of the Ministry of Transport of Ukraine of 16.04.2003 №293 as amended by the order of Ministry of Transport of Ukraine of 31.01.2004 p., №62. (registered with the Ministry of Justice of Ukraine 23.02.2004, №238/8837) / / Official Herald of Ukraine. - 2003. - №18.

2. Doc 8643/37. Aircraft type indicators: - 37th ed. - Montreal: ICAO, 2009.

3. Doc 4444-ATM/501. Air traffic management: - 15th ed. - Montreal: ICAO, 2007.