B-7-A RSA overrun-overshoot - FAA

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					32nd Annual Airport Conference
Hershey, PA – Mar 5 2009

             ACRP Report 3
   Analysis of Aircraft Overruns and
 Undershoots for Runway Safety Areas
                                 Manuel Ayres, Ph.D.
Objective
   Present the methodology developed under the
    Airport Cooperative Research Program
    (ACRP) to assess risk of aircraft overrun and
    undershoot outside the Runway Safety Areas
    (RSA)




                                     Expanding the Realm of Possibility
Outline
    Introduction
    Accident Database
    Modeling risk
    Analysis Process
    Example
    Conclusions




                         Expanding the Realm of Possibility
The Safety Risk Management Cycle
                                  1
                           Describe System


                5
       Prioritize, Treat
                                                     2
      and Monitor Risk
                                             Identify Hazard




                      4                    3
                 Assess Risk         Determine Risk

                       Severity
                      Likelihood




                                                      Expanding the Realm of Possibility
Risk Assessment


   ACRP Report 3 – Analysis of
    Aircraft Overruns and Undershoots
    for Runway Safety Areas
   Methodology for quantitative
    assessment of Runway Safety
    Areas




    http://onlinepubs.trb.org/onlinepubs/acrp/acrp_rpt_003.pdf

                                                 Expanding the Realm of Possibility
Overruns and Undershoots
  Overrun (Landing or Takeoff)



             Runway                                              RSA




                            Undershoot (Landing)


   RSA                                 Runway




                                                Expanding the Realm of Possibility
Accident and Incident Database




                     ~ 300 fields/record   • Flight Data
                     • Basic Data          • Obstacles
   Access Database   • Aircraft Data       • Terrain
                     • Airport Data        • Injuries
                     • Consequences        • Weather
                     • Causal Factors      • Wreckage




                                                 Expanding the Realm of Possibility
Database Sources
    NTSB Accident Database & Synopses
    FAA Accident/Incident Data System (AIDS)
    FAA/NASA Aviation Safety Reporting System (ASRS)
    Transportation Safety Board of Canada
    ICAO Accident/Incident Data Reporting (ADREP) system
    Australian Transport Safety Bureau (ATSB)
    French Bureau d'Enquêtes et d'Analyses pour la Sécurité de
     l'Aviation Civile (BEA)
    UK Air Accidents Investigation Branch (AAIB)
    New Zealand Transport Accident Investigation Commission
     (TAIC)
    Air Accident Investigation Bureau of Singapore
    Ireland Air Accident Investigation Unit (AAIU)
    Spain Comisión de Investigación de Accidentes e Incidentes
     de Aviación Civil (CIAIAC)

                                              Expanding the Realm of Possibility
Example Data – NTSB Dockets




                              Expanding the Realm of Possibility
Example Data – NTSB Dockets (cont’d)




               …and there is more!




                                Expanding the Realm of Possibility
Example Incident Report – prior to 1995




               …fields up to 115 characters!




                                Expanding the Realm of Possibility
Google Earth
               St Louis International Airport – RWY 30R




                                          Expanding the Realm of Possibility
…”THE CAPT APPLIED SOME REVERSE THRUST AND SEEING THAT DEP WAS A POSSIBILITY,
TURNED TO THE L IN AN ATTEMPT TO MISS STRUCTURES STRAIGHT AHEAD AND TO KEEP
THE ACFT ON RWY 24. I IMMEDIATELY PREPARED TO RUN THE EMER EVAC CHKLIST. I
COMMUNICATED WITH ATC THAT THE ACFT WAS OFF THE PREPARED SURFACE”.
Summary of Events
- from 1982-2006 -

                                  Accidents/Incidents by Type
                           180
                           160
                           140
        # of Events




                           120
                           100
                            80
                            60
                            40
                            20
                             0
                                  LDOR             LDUS                  TOOR
                      Accidents    121               48                    55
                      Incidents    153               45                    37
                                                Type of Event




                                                                Expanding the Realm of Possibility
Normal Operations Data
    Approach
       Evaluate number of operations that experience certain factors
         benignly, singly and in combination.
       Generate risk ratios and quantify the importance of risk factors

    Source: FAA's Enhanced Traffic Management System Counts
     (ETMSC) & the National Oceanic and Atmospheric
     Administration's (NOAA) weather database
    Final NOD sample consists of 24,240 flights, from 78 selected
     airports, from 2000 to 2005




                                                   Expanding the Realm of Possibility
Data Normalization
     Small pool of relevant data
      available
     Data from different airports,
      operation conditions, aircraft
      performance
     Correct distances for
        Temperature
        Elevation
        Terrain & obstacles




                                       Expanding the Realm of Possibility
Risk Assessment Methodology
                            Three-Part Risk Model

      Event              Location                Accident
                                                                                 Risk
    probability         probability            consequences

                                                  Location                       High
                                                                                 High
    Operating          Operation                 probability,
    conditions      conditions, terrain       obstacle location,               Medium
                                                                               Medium
                                               size and type,
                                                aircraft type                     Low
                                                                                  Low


   Event Probabilty:                 function of type of operation and
                                      weather conditions
   Location Probability:             function of distance from runway end
   Consequences:                     function of type of obstacle, location,
                                      aircraft type



                                                               Expanding the Realm of Possibility
ACRP Report 3
   Approach to quantitatively estimate the probability that an aircraft
    will exit the runway and stop beyond a given distance from the
    runway end



                                                  x

                                        y
                                   y

          Stop Location                                                     by m
      Probability Distribution              P{Location  y}  e
                                                  RSA
                                                                            ax n
                                            P{Location  x}  e
                                                       Expanding the Realm of Possibility
Model Factors

   Aircraft characteristics
      Type
      Weight
   Weather Conditions
      Rain
      Crosswind
      Visibility
      Ceiling, etc.
   Terrain conditions in the RSA
   RSA geometry
   Characteristics of obstacles



                                    Expanding the Realm of Possibility
A Simple Example

    Probability of Event (e.g. LDOR)   1




                                            Possible cut-off points
                                       P2




                                       P1
                                       0
                                                         XW1      XW2
                                                                        Risk Factor (e.g. x-wind)




                                                                                    Expanding the Realm of Possibility
Location Probability for LDOR
                                                            Landing Overruns
                                                          Incidents & Accidents

                                        100%

       Probability WL Exceed Distance   90%

                                        80%

                                        70%

                                        60%

                                        50%

                                        40%

                                        30%

                                        20%

                                        10%

                                         0%
                                               0   500   1000      1500    2000     2500       3000   3500   4000
                                                                Distance from Threshold (ft)




                                                                                           Expanding the Realm of Possibility
Modeling Consequences
                        ax n
 P{Location  x}  e
             100%
                            Stop Location
                        Probability Distribution


                                                Obstacle



                           D     D+
                    D is distance to Obstacle




                                                       Expanding the Realm of Possibility
Modeling Approach


         Lateral Location
      Probability Distribution

                                      Psc



                                      Obstacle

  y


                                 y1              y2


                                                  Expanding the Realm of Possibility
Example – Runway Safety Area




                           Expanding the Realm of Possibility
Existing Conditions - Example



    630 ft

                RSA




                 540 ft




                            Expanding the Realm of Possibility
The SRM Process to Evaluate Risk




                                        RSA



1 - System: RSA at arrival end of Rwy 34
2 - Hazard: non-standard RSA
3 - Risk
         Aircraft undershooting Rwy 34 outside the RSA
         Aircraft overrunning Rwy 16 when landing and stopping beyond the RSA bounds
         Aircraft overrunning Rwy 16 when aborting takeoff and stopping beyond the RSA
4 - Risk Assessment: ???
5 - Treat and Monitor Risk: based on step 4




                                                                   Expanding the Realm of Possibility
Analysis
   Historical operations (1 year of data)
   Weather conditions for each operation
   RSA boundaries
   Location and dimensions of obstacles
   For each aircraft operation and each scenario, estimate
       Probability aircraft overruns or undershoots RSA
       If an incidents occurs, the probability the aircraft will stop
        (or, for undershoots, touch down) outside the RSA
   Estimate risk




                                                   Expanding the Realm of Possibility
Improvement Scenario – FAA (500 x 1000 ft)




                   FAA




                                Expanding the Realm of Possibility
Example Results
                                        RSA 34 - LDOR
               4000                                                                 100%
                                                                                    90%
               3500                                                Frequency        80%
   Frequency

               3000                                                Cumulative %     70%
               2500                                                                 60%
               2000                                                                 50%
               1500                                                                 40%
                                                                                    30%
               1000
                                                                                    20%
                500                                                                 10%
                  0                                                                 0%




                                                                              e
                       8

                       8

                       7

                       7

                       7

                       7

                       7

                       7

                       7

                       7

                       7

                       7

                                                                            or
                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0

                    -0
                  3E

                  0E

                  2E

                  6E

                  1E

                  6E

                  0E

                  5E

                  0E

                  4E

                  9E

                  3E

                                                                            M
                2.

                7.

                1.

                1.

                2.

                2.

                3.

                3.

                4.

                4.

                4.

                5.
                                            Probability Interval

   RSA                Parameter                 Estim. Value
   34                 Average Probab.           1.7E-07
   (LDOR)             Years for one event       62
                      Accum % Ops with          1.8%
                      Prob > 10-6



                                                                             Expanding the Realm of Possibility
Possible Comparisons
 RSA                          16        34        07          25         Total
 Average Probability for    2.6E-07   2.8E-07   3.3E-07   2.5E-07       4.1E-07
 Existing (non-
 complying) Conditions
 Movements      LDOR        53,000    10,000    4,200       2,300
 Challenging    TOOR        51,200    11,300    5,800       1,200
 the RSA        LDUS        10,000    53,000    2,300       4,200
 % Reduction for FAA         22%        8%        3%         0%           33%
 Scenario (500 x 1000 ft)
 Rank for Improvements        1         2         3          N/A




                                                          Expanding the Realm of Possibility
Conclusions
   RSAs are essential areas that can significantly
    improve safety when aircraft incidentally departs or
    touches down outside the runway paved areas
 Using the SRM process of an SMS and the ACRP
  analysis methodology, it is possible to quantitatively
  evaluate risk associated to non-standard RSA
 The analysis is rational and based on evidence of
  accidents and incidents, and can help airport
  operators decide which improvements will be most
  beneficial to operations safety

                                            Expanding the Realm of Possibility

				
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posted:9/14/2011
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