ACRP Report 3

1. 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.

2. 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)

3. Outline • Introduction • Accident Database • Modeling risk • Analysis Process • Example • Conclusions

4. The Safety Risk Management Cycle

5. 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

6. Overruns and Undershoots Overrun (Landing or Takeoff) Runway RSA Undershoot (Landing) Runway RSA

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

8. 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)

9. Example Data – NTSB Dockets

10. Example Data – NTSB Dockets (cont’d) …and there is more!

11. Example Incident Report – prior to 1995 …fields up to 115 characters!

12. Google Earth St Louis International Airport – RWY 30R

13. …”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”.

14. Summary of Events- from 1982-2006 -

15. 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

16. Data Normalization • Small pool of relevant data available • Data from different airports, operation conditions, aircraft performance • Correct distances for • Temperature • Elevation • Terrain & obstacles

17. Three-Part Risk Model Risk Event probability Location probability Accident consequences Location probability, obstacle location, size and type, aircraft type Operating conditions Operation conditions, terrain High High Medium Medium High Low Low Medium Low Risk Assessment Methodology • 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

18. x y Stop Location Probability Distribution RSA 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 y

19. Model Factors • Aircraft characteristics • Type • Weight • Weather Conditions • Rain • Crosswind • Visibility • Ceiling, etc. • Terrain conditions in the RSA • RSA geometry • Characteristics of obstacles

20. A Simple Example 1 Probability of Event (e.g. LDOR) Possible cut-off points P2 P1 0 XW1 XW2 Risk Factor (e.g. x-wind)

21. Location Probability for LDOR

22. Modeling Consequences 100% Stop Location Probability Distribution Obstacle D D+ D is distance to Obstacle

23. Lateral Location Probability Distribution Psc Obstacle y y1 y2 Modeling Approach

24. Example – Runway Safety Area

25. Existing Conditions - Example 630 ft RSA 540 ft

26. The SRM Process to Evaluate Risk 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 RSA

27. 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

28. Improvement Scenario – FAA (500 x 1000 ft) FAA

29. Example Results

30. Possible Comparisons

31. 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