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.

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

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 http://www.trb.org/crp/acrp/acrp.asp

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

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

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

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

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

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

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

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

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

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

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

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)

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

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 > 12500 lb Excluded single engine and piston engine aircraft

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

Accident Location y x Wreckage Location

Summary Table

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

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

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

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

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

Risk Models

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.)

Location Model - Overruns Stop Location Probability Distribution RSA x y

Location Model - Overruns Decreasing Probability RSA Frequency Contours

Location Model - Undershoots Touchdown Location Probability Distribution RSA x y

Consequences Model

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

Contact Info ARA Jim Hall, 601-629-6165 jhall@ara.com Manuel Ayres 410-540-9949 mayres@ara.com ACRP Staff Michael R. Salamone (202) 334-1268 msalamone@nas.edu

Questions?