1. Aircraft Overrun and Undershoot Analysis for Runway Safety Areas
ACRP 4-01
Aircraft Overrun and Undershoot Analysis for Runway Safety Areas
Manuel Ayres, Ph.D.

2. Summary Objective Approach Functional Hazard Analysis
Accident/Incident Database
Normal Operations Data
Normalization
Risk Models
Analysis Software

3. ACRP 4-01 Project Airport Cooperative Research Program (ACRP)
Objective: develop near-term practical solutions to problems faced by airports
Industry-driven program focused on applied research to airport operators
Authorized in December 2003 as part of the Vision 100-Century of Aviation Reauthorization Act
Oct 2005, FAA executed a contract with the National Academies (through TRB) to serve as manager of the ACRP
Program oversight and governance are provided by representatives of airport operating agencies

4. Project Team ARA Team ARA Loughborough University ESR-Technology
Jim Hall – PI
Manuel Ayres – PM
Rich Speir
Hamid Shirazi
Tara Puzin
Other
Loughborough University
David Pitfield
Robert Caves
Andrew Appleyard
Derek Wong
ESR-Technology
Mark Eddowes
ACRP Staff Responsible
Michael R. Salamone, CM

5. Background 71% of Accidents occur during landing and take-off
41% of onboard and 3rd party fatalities
Landing overruns, landing undershoots, take-off overruns, and crashes after take-off
Runway safety areas (RSA) are prescriptive resulting in ‘averaged’ degrees of protection
Current RSA dimensions based on studies by FAA in the 80s

6. Reason’s Swiss Cheese The cheese is moving!
Holes are active failures & latent conditions
Accidents/ Incidents
The cheese is moving!
Successive layers of defenses,
barriers and
Safeguards
Hazards

7. Objective of ACRP 4-01
Collect historical information related to overrun and undershoot accidents and incidents
Develop risk models for overrun and undershoot events
Evaluate risks associated with standard and non-standard RSA dimensions
Develop prototype software for overrun and undershoot risk analysis

8. Functional Hazard Analysis
Formal and systematic process for the identification of hazards (similar to hazard and operability (“HAZOP”) studies)
Gathering together a multi-disciplinary team
Determine relevant causal factors of overrun and undershoot accidents and hazards to aircraft associated with airport operations
Support the data collection and development of risk models

9. Functional Hazard Analysis
Categories
Aircraft characteristics and system faults
Airport characteristics and system faults
Weather characteristics
Pilot related issues

10. Landing Overruns – Major Factors
Weather
Tailwind
Cross wind
Visibility
Ceiling
Airport
Surface contaminants and friction (water, snow, ice, rubber deposits)
Pilot
Landing long
Landing high
Landing fast
Aircraft
System faults

11. Takeoff Overruns – Major Factors
Weather
Tailwind
Airport
Surface contaminants and friction (water, snow, ice, rubber deposits)
Pilot
Delay to abort
Aircraft
System or component malfunction require to abort takeoff

12. Landing Undershoots – Major Factors
Weather
Visibility
Ceiling
Wind variations (gusts, shear)
Airport
Surface contaminants and friction (water, snow, ice, rubber deposits)
Pilot
Visual illusion

13. Visual Illusion A B Runway dimensions Runway and terrain slope
Intensity of runway lighting
Visibility
Wet runway
Crosswind
Source: David Newman and Flight Safety Foundation

14. Other Factors Wind variations (gusts, shear) Temperature, Altitude
Landing/Takeoff Distance (LDA vs. LDR; ASDA vs. ASDR)
Slopes (longitudinal and transverse)
Runway profile
System faults
Unstabilized approach
“Press-on-itis”
Incorrect (delay) application of thrust reverse, spoilers and brakes
‘Over-consideration’ for comfort
Incorrect interpretation of reported operation conditions
Selecting wrong runway
Weight
Availability of navigational aids
Approach too low
Attempt to land too close to arrival end of the runway

15. Database Sources
NTSB
Accident Database & Synopses (Accidents and Incidents)
FAA
Aviation Safety Reporting System - ASRS (Incidents)
Accident/Incident Data System - AIDS (Incidents)
Transportation Safety Board of Canada (Accidents & Incidents)
UK CAA-Safety Regulation Group (SRG) Mandatory Occurrence Reporting Scheme (MORS) Database (Accidents & Incidents)
Australian Transport Safety Bureau (Accidents & Incidents)

16. DATA Collection Accidents Incidents Consequences Cost of Investigation
& Availability of
Information
# Reported Events
Probability and
# of Events

17. Database Filters Both accidents and incidents
North American, Western European, Australia, New Zealand
Fixed-wing
Part 121, 125, 129, 135 and Part 91F Operations
Aircraft with MTOW > lb
Excluded single engine and piston engine aircraft

18. Access Database ~ 300 fields/record Basic Data Aircraft Data
Airport Data
Consequences
Details
Flight Data
Obstacles
Terrain
Injuries
Weather
Wreckage

19. Accident Location y x
Wreckage Location

20. Summary Table

21. 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) & a National Oceanic and Atmospheric Administration's (NOAA) weather database

22. Normal Operations Data
NOD was sampled from a total of 78 selected airports
Sampled airports account for 48,924,040 operations from 2000 to 2005 inclusive (25.5% of all relevant traffic in the period)
Flights on the first day of February, May, August and November of 2002, 2003 and 2004 were sampled to constitute the NOD sample
After eliminating incompatible traffic, the final NOD sample consists of 24,240 flights

23. Normalization Small pool of relevant data available
Data from different airports, operation conditions, aircraft performance
Comparing apples and apples
Only raw distances between the final wreckage location and the runway end have been used to develop current RSA recommendations
Assume an infinitely long hard surface runway

24. Normalization Procedures
Correcting (overrun and undershoot) distances for
Temperature
Altitude
Slope (when available)
Aircraft performance
Landing/Takeoff distance available
Terrain (type, slope)

25. Risk Models Frequency Location Severity (Injuries, Cost)
Landing overrun
Takeoff overrun
Landing undershoot

26. Risk Models

27. Frequency Models
Probability = Ni/a / Nn (under certain operation conditions)
P{Accident_Occurrence} is the probability (0-100%) of an accident type occur given certain operational conditions.
Xi = f(runway friction, ceiling, visibility, crosswind, tailwind, etc.)

28. Location Model - Overruns
Stop Location
Probability Distribution
RSA x y

29. Location Model - Overruns
Decreasing Probability
RSA
Frequency Contours

30. Location Model - Undershoots
Touchdown Location
Probability Distribution
RSA x y

31. Consequences Model

32. Prototype Analysis Software
User-friendly application in Visual Basic for MS Excel
Input operation conditions
Normalize the data
Estimate risks
Denormalize data

33. Contact Info
ARA
Jim Hall,
Manuel Ayres
ACRP Staff
Michael R. Salamone
(202)

34. Questions?