safety assessments and aeronautical studies events/safety seminar 2008... · aeronautical studies /...

/Aeronautical Studies18.11.2008 –

Aeronautical Studies / Safety Assessmentsin the context of SMS

– Theory and Practice –

ACI World Safety Seminar, Beijing PRC, 18.-19. November 2008

Dr. Holger Schulz – CEO airsight [email protected]

Aeronautical Studies18.11.2008 –

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SafetyAssurance

Context

Safety Risk Management is one of the four pillars of SMS

Safety Policyand

Objectives

Source: U.S. Department of Transportation, FAA, AC 150-5200-37, Introduction to SMS for Airport Operators, February 2007ICAO State Letter (AN 12/51-07/74), 07.12.2007

Hazard IdentificationRisk AssessmentRisk Mitigation…

SafetyPromotion

SMS

Safety RiskManagement

SMS:Safety Management System


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/Need of Safety Assessment

The need of a Safety Assessment could arise fromImplementation of SMSIdentification of hazardsAudits, InspectionsChange of infrastructure (e.g. airport expansion)Change of operation (e.g. implementation of A380)Change of regulations (e.g. Annex 14)Compliance checksCertification of aerodromes

Safety Assessment is a commonly used method and widely accepted, e.g. Nuclear industryAircraft Manufacturer (e.g. FAR 25/CS-25)ANSP (e.g. ESARRs für ATM)AACG (A380 Airport Compatibility Group)References in aerodrome related ICAO Docs

Annex 14Doc 9774 (Manual on Certification of Aerodromes)Doc 9859 (Safety Management Manual)

FAR:Federal Aviation Regulations

CS:Certification Specifications

ANSP:Air Navigation Service Provider

ESARR:EUROCONTROL Safety Regulatory Requirement

ATM:Air Traffic Management

AACG:A380 Airport Compatibility Group

ICAO:International Civil Aviation Organisation


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/How to conduct a Safety Assessment

„Just“ identifyhazards

calculateprobabilityseverity

compare toTarget Level of Safety (TLS)

TLS:Target Level of Safety

unacceptable

unacceptable

undesirable

acceptable

reasonable probable

unacceptable

unacceptable

undesirable

undesirable

frequent

unacceptable

unacceptable

undesirable

acceptable

remote

unacceptable

undesirable

undesirable

acceptable

extremely remote

undesirable

undesirable

acceptable

acceptable

extremely improbable

Probability

catastrophic

hazardous

major

minorSeverity

Risk


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/The „little“ problems of Safety Assessments

In generalRisk quantification (how much risk is inherent)TLS (how much safety/risk is adequate)Method (how to do it)

For possible solutions one canconduct trials (sometimes you better don‘t)use experts opinion (not always appropriate method)refer to historical data (e.g. accident data base)conduct simulations (mostly expensive)

Some Examples and Case StudiesRunway End Safety Area (RESA) – risk quantificationTaxiway Separation – TLS derivation and mitigation measuresAirplanes and Ships – risk networksRunway Holding Positions – development of new modelsPilots confusion/blinding – qualitative assessments



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/Risk Quantification: How much safety is inherent to a RESA?

Depending on the specific airports infrastructure and operations, e.g.

Operations (LDG, DEP)Approach (PA, NPA)Traffic Mix (jet, prop)Weather conditions (dry, wet)

UNDERSHOOT RISKILS 1,04E-09LOC (PAPI on) 5,37E-06VOR (PAPI on) 4,43E-05VOR (PAPI off) 1,69E-03

OVERRUN RISKTake Off 4,67E-07LDG (PA) 4,62E-07LDG (NPA) 3,06E-06

RESA:Runway End Safety Area

PA:Precision Approach

NPA:Non Precision Approach

LDG:Landing

ILS:Instrument Landing System

LOC:Localizer Approach

PAPI:Precision Approach Path Indicator

Precision Approach only

Non-Precision Approach only

Models from different Risk Assessments

Large accident/incident data baseFlight Simulator Trails

Example for a risk quantification taking into account one airport‘s individual situation

Jets only (Precision Approach)

Prop only (Precision Approach)

Dry only (Precision Approach)

Wet only (Precision Approach)


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/Taxiway Separation Study:TLS Derivation – Risk Quantification – Mitigation Measures

40.2676.13Current situation at the region of interest47.580Code letter E ICAO Annex 14 requirements

40.566.5Code letter D ICAO Annex 14 requirements

TWY centre line to object [m]

TWY centre line to TWY centre line [m]

Pier A

Pier B

TWY STWY R4


TWY:Taxiway


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/Taxiway Separation Study: TLS Derivation

ProblemsMultiple hazards

from a FHA-Workshop with all Stakeholders

No TLS availablefor ground operations in a local operational area

Review of existing similar TLS (NTSB, ICAO, ECAC)choice of most conservative TLS: ICAO A-SMGCS

1x10-8 collision per movement on ground

conducting a time based fraction (for local operational area)considering number of relevant movementsresulting in 8.6 x 10-6 collisions per year

FHA:Functional HazardAnalysis


NTSB:National Transport SafetyBoard

ICAO:International Civil Aviation Organization

ECAC:European Civil AviationConference

A-SMGCS:Advanced SurfaceMovement Guidance and Control System


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/Taxiway Separation Study: Risk Quantification

h4

h2 h2 h2 h2 h6

n/ah1 h2 h3 h4 h5 h6

hazards

risk


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/

n/a

Taxiway Separation Study: Risk Quantification

h5

h3

h2 h2h1 h1

h2 h2h2h2h2 h6

…

Total Risk5.3x10-51

TLS8.6x10-6ris

k

h1 h2 h3 h4 h5 h6hazardshazards


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/Taxiway Separation Study: Quantification of Mitigation Measures

h4h1

h6

h1 h2 h3 h4 h5 h6

n/a

limitation of aircraft size for one standoperational restriction or limit push back deviationdisplacement of holding positions K & M

Total Risk5.3x10-51

TLS8.6x10-6 1.

1x10

-6

2.1x

10-6

h4

h1

risk

hazards


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/Assessment on temporary mobile objects: Risk Networks

Approaching aircraft‘s flight path is penetrated by large shipsMethod ?Conduct trials ? Available data bases ?Risk calculation ?

SolutionUsing experts’ opinionsand Bayesian networks



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/Bayesian Networks

frequencies: derived from statistics

A/C:Aircraft


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/Frequency and Probability in Bayesian Networks

probabilities: derived from experience of domain experts

Air Traffic Controllers: „this happened 5 times within the last 10 years“

with 500 approaches p.a. this yields 1 in 1000 approaches


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The problemaircraft penetrate obstacle limitation surfacesdisplacement of holding positions has negative impact on capacityICAO collision risk model not valid below OCH

Assessment on Runway Holding Positions: Model development

OCH:Obstacle Clearance Height


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SolutionDevelopment of

collision risk model for visual segment (PA and NPA)based on ICAO Balked Landing Study (Circular 301)

Application of model to calculate risks

Assessment on Runway Holding Positions: Model development

PA:Precision Approach



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/Pilots confusion/blinding: Qualitative Safety Assessment

The problemPilots might get blinded by lights from

CarsTrains

Pilots might misinterpret runway withRoad


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/Safety Assessment: Pilots confusion/blinding

SolutionVisualization within a Flight SimulatorHazard IdentificationDefinition of critical visual situations

night, offset approaches, crosswind,lights on road, NPA, …

Assessment of visual cues pilots receive No TLS, no quantification of risk

judgment purely based on opinion of experts and CAA CAA:Civil Aviation Authority



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/Conclusions

Safety Risk Management is a crucial part of SMS but maybe the most difficult

There is always the same theoretical approach to Risk AssessmentBut different methods in real life

from simple qualitative expert‘s opinionto complex quantitative network assessment

Safety Assessments have to be SystematicallySerious and robustwell communicated (with CAA)

Safety Assessments are sometimes very complex and expensive But give the opportunity to cope with special situations(e.g. non-compliance)

So rather see it as a chance than as a burden

CAA:Civil Aviation Authority


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/Conclusions

Safety Risk Management is a crucial part of SMS but maybe the most difficult

There is always the same theoretical approach to Risk AssessmentBut different methods in real life

from simple qualitative expert‘s opinionto complex quantitative network assessment

Safety Assessments have to be SystematicallySerious and robustwell communicated (with CAA)

Safety Assessments are sometimes very complex and expensive But give the opportunity to cope with special situations(e.g. non-compliance)

So rather see it as a chance than as a burden

CAA:Civil Aviation Authority

Thank you for your attention !

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