Slide 1

Firdu BatiVideo Presentation onAviation Safety

IntroductionAviation safety is very important to the viability of the industry in generalFrequent Fatal accidents can have high negative effect in the perception of the flying public and damages the industrys reputationFortunately, aviation accidents are very rare, and only a fraction of those accidents result in fatalitiesThe likelihood of being killed in aviation accident is extremely small, in the order of millionth

Death RiskAn objective measure of aviation safety is the death risk of flyingHow likely it is a passenger wouldn't survive any randomly chosen flightTo determine the death risk, we rely on statistics of various kind. We need to be careful about the type of statistics to consider for death risk analysisStatic of fatal accidents per hours flown may not be a good measure. - The variable fatal accident may represent an accident with a single fatality or entire passengers of the flight with the same weight. - Similarly, hours flown ignores some important facts such as most accidents happen in certain phase of flights regardless of number of hours flown

Death RiskHull loss statistic is more useful to aircraft manufactures than assessing death risk- An accident with heavy damage to the aircraft might involve no deaths at allPassengers killed to passengers carried statistic is a good measure of proportions, but still dont truly measure death risk- The risk is not proportional by the number of passenger in a given accident, i.e. accident with higher number of fatalities is not proportionally riskier than with small number of fatalitiesIn general, it is better to avoid directly involving the number of deaths in the numerator of death risk statistics

Death Risk Using Q-statisticThe Q-statistic answers the probability of death given a random flight of N flights with xi fraction of fatalities- Let there be N flights to choose from- A flight i is picked with 1/N probability- xi is the fraction of deaths in flight i- The conditional probability of death in flight i is xi /N- Full Loss Equivalent-FLE is the sum of the fraction, xi - Overall probability, which is the death rate over all N flights is given by:Q = i=1-N xi /N = FLE/N

Advantages of Using Q-statisticQ-statistic allows to treat accidents with higher survival rate differently than with lower survival rateIt doesnt give different weights to Distance flown and duration of flightThe conditional probability calculation involved in Q-statistic is very easyQ-statistic calculated using recent data can be used to estimate death of on other flights

Calculated Q-valuesUsing data of scheduled passenger jet flights in First World countriesIn year 1990 to 1999, 70 million flights performed with only 10 of them involved in fatal accidentsAverage fraction of the 10 flights is 56%Q= 10*0.56/70,000,000 = .00000008 which equates to approximately 1 fatality in 13 million flights, a very, very small fractionWith such a small rate, a person can fly everyday for 36,000 years before killed in a flight accident

Calculated Q-valuesRecent statistics show even impressive results- From 2000 to 2008, there were only 2 accidents, one in Kentucky in 2006 with 100% fatality and another one in Madrid in 2008 with 90% fatality of 80,000,000 flights total- Average fraction of the 2 fatal flights is 95%Q= 2*.95/80,000,000 = .000000024 which equates to approximately 1 fatality in 42 million flightsWith such tiny rate, a person can fly everyday for more than 116 thousand years before killed in a flight accidentNote: Not considering survivability, the death risk tends to be higher

Statistic Across the WorldFirst World Domestic- 1960-1969 1 in a million- 1980 19891 in four million- 2000 20071 in 80 millionFirst World International- 1960-19691 in 200 thousand- 1980 19891 in four million- 2000 20071 in 9 millionBetween First and Developing World- 1960 19691 in 200 thousand- 1980 1989 1 in 600 thousand- 2000 20071 in 1.5 millionWithin Developing World1960 19691 in 100 thousand1980 19891 in 400 thousand2000 2007 1 in 2 million

Comparing Safety Among OperatorsWith such a small overall death rate in the First World, it would be difficult to make detailed comparison among individual airlinesOne approach would be to compare the rate of precursors to accidents Using Incidents and non-fatal accidents to compare death rate among airlines however might not reflect the true picture.Typically, airlines learn from incidents and take corrective actions to minimize the occurrence of accidents from same operational errors Even when a First World airline is compared with Third World airline in the same environment/route, the rate is surprisingly similar. Hence, there is no statistically significant data to claim that one airline is better than another in terms of safety

Future Aviation Safety AssessmentThe fact that aviation accidents rate have reduced to such level in recent decades is a testament to the safety record of the industryHowever, how do we improve safety further in the presence of almost non existent accidents from which operators and regulators learn and take actions to prevent such happeningsBecause of that, since the early 1970 the industry and regulators started compiling data about incidents which are precursors to accidentsThere are over 70 safety action programs run by airlines, NASA and the FAA to collect data that lead to incidents which have the potential to lead to accidentsAs a result there are enormous amount of data to analyze and assess the future of aviation safety, and the likelihood of catastrophic accidentsLinear and Quadratic models can be used to assess runway and mid air collision risks of future operations

ConclusionThe statistics undeniably tells the whole picture, safety of aviation has been improving at an impressive rate in spite of increasing serviceHowever, the system is not completely free of accidents, when aviation accidents do happen, they leave large dents in the industry and erode public confidenceWe have to continue to improve the system as challenging as that maybeWith the expected increase of aviation services and the introduction of new procedures and application of latest technologies, the challenges will be even greaterNo matter how challenging the task is the safety of aviation should not be comprised and needs to continue to improve to sustain the viability of this vital industry

ReferencesChapter 11, Aviation Safety from Global Airlines Industry by Belobaba, Odoni, and BarnhartAviation Safety Lecture Notes by Dr. Lance Sherry