„Fuzzy Expert” System for Determination of

Runways in Use Case Study: Zurich Airport

Fedja NetjasovUniversity of Belgrade

Faculty of Traffic and Transport EngineeringDivision of Airports and Air Traffic Safety

Airport Traffic Control Tasks

Monitoring of departing and arriving traffic at the airport with aim of securing:

- safe,- accurate and- expeditious traffic.

This is obligation of Air Traffic Controllers who are located in the Airport Control Tower.

Airport Traffic Controller Duties

Most important ones are:

• Airport Traffic Monitoring (directly through the window or by binoculars);

• Radio Comunication with aircraft pilots and ground handlung personal;

• Determination of runway(s) in use.

Determination of runways in useProblem definition

For the case of multiple runways:

depending on meteorological conditions

and planned traffic demand, airport traffic

controller determine the runways in use

trying to “maximize” utilization of available

airport capacity and “minimize” the noise level.

Problem nature

• Real Time Combinatorial Problem;

• Large number of feasible combination of runways;

• Large number of operational constraints;

• Conflicting Goals;

• Decision making process is dependant of controller’s subjective judgments.

Reasons for development of “fuzzy expert” model

• Usage of input data in different form (linguistic, quantitative);

• Individual differences between controllers (personal experience, age, personality, etc.);

• Better satisfaction of given criteria (maximization of capacity, minimization of noise level, etc.);

Conceptual model for determination of runway in use

• Determination of meteorological conditions on the basis of visibility and ceiling;

• Determination of operational concept in use on the basis of meteorological conditions, wind direction and runway condition;

• Aircraft assignment to runways in use on the basis of operational concept in use and estimated number of departures and arrivals

Ceiling

Visibility Wind directionrwy condition

Hourly number ofdepartures and

arrivals

Fuzzy rules

Meteorologicalconditions

(VMC,MMC, IMC)

START START

Operational concept

and procedure in use

Rwy in use andtraffic assignment

on them

STOP

Fuzzy model 1

Rule base

START

Fuzzy rules

“Estimated” hourlynumber of departures

and arrivals

Fuzzy model 2

Fuzzy Model 1

Serves for the determination of meteorological conditions at a specific time using the fuzzy variable visibility and ceiling.

1 2 3 4 5 Visibility (km)0

1

Small Midlle Large

Ceiling (ft)1000 2000

1

Low Midlle High

0

Fuzzy Model 1 (cont.)

The output of the model is presented as fuzzy variables “preference of meteorological condition (VMC/MMC/IMC)”.

0.5 1 Preferency ofVMC/MMC/IMC

1

Low Midlle High

0

Fuzzy Model 2

Using fuzzy variables “planned hourly number of departures (arrivals)” and “absolute difference” determines the “estimated” number of departures and arrivals.

Absolute difference250

1

Small Midlle Large

11

Fuzzy Model 2 (cont.)

Hourly number of arrivals20 400

1

Small Midlle Large

15

45 Hourly number of departures0

1

Small Midlle Large

20

Fuzzy Model 2 (cont.)

Output from Fuzzy model 2 is presented as fuzzy variables “preference that number of departures (arrivals) is small/middle/large”.

0.5 1 Preferency that numberof dep (arr) is small/midlle/large

1

Small Midlle Large

0

Rule Base

Based on results from Fuzzy Model 1 and 2, and using additional information on wind direction and runway conditions, as a result gives us the operational concept in use and distribution of traffic (by aircraft category) on runways in use.

C

Large

Small Large

Small

DEPTP = RWY16, DEPMJ = RWY14, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY10 and RWY14, ARRHJ = RWY14

DEPTP = RWY16, DEPMJ = RWY14, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY14, ARRHJ = RWY14

DEPTP = RWY16, DEPMJ = RWY14, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY14, ARRHJ = RWY14

DEPTP = RWY16, DEPMJ = RWY14 and RWY 16, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY10 and RWY14, ARRHJ = RWY14

DEPTP = RWY16 and RWY14, DEPMJ = RWY14 and RWY16, DEPHJ = RWY14 and RWY16 ARRTP = RWY10, ARRMJ = RWY10 and RWY14, ARRHJ = RWY14

DEPTP = RWY16, DEPMJ = RWY14 and RWY16, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY14, ARRHJ = RWY14

DEPTP = RWY16, DEPMJ = RWY14 and RWY 16, DEPHJ = RWY14 ARRTP = RWY10, ARRMJ = RWY14, ARRHJ = RWY14

DEPTP = RWY14 and RWY16, DEPMJ = RWY14 and RWY 16, DEPHJ = RWY14 and RWY16 ARRTP = RWY10, ARRMJ = RWY14, ARRHJ = RWY14

DEPTP = RWY14 and RWY16, DEPMJ = RWY14 and RWY16, DEPHJ = RWY14 and RWY16 ARRTP = RWY10, ARRMJ = RWY10 and RWY14, ARRHJ = RWY14

Middle Middle

DecisionOprational

conceptNumber of

arrivalsNumber ofdepartures

A

Numerical example

Meteorological data are:visibility – 3000 m;ceiling – 1100 ft;wind direction – 900;runway condition – wet.

Traffic data planned for next hour are: planned number of departures - 29; planned number of arrivals - 11;

Concept A Concept B

Concept C Concept D

Determination of meteorological condition

VMC

Determination of number of departures

MIDDLE

Determination of number of arrivals

SMALL

Determination of final results

Conclusion and Further Research

• Developed model could serve for evaluation or for suggestion of decision;

• Model could be easily applied for any other airport;

• This is prototype of a model, so further verification and additional “fine tuning” is required.

University of Belgrade Faculty of Transport and Traffic Engineering

Department of Air TransportDivision of Airports and Air Traffic Safety

http://apatc.sf.bg.ac.yu Vojvode Stepe 305, 11000 Belgrade

Serbia and Montenegrotel: +381 11 3091 352fax: + 381 11 466 294

Thank you for

your attention