Chang & Wong carried out a study in 2012 examining the human risk factors associated with pilots in runway incursions. The aim of the study was to identify key risk factors and categorize them appropriately according to both the amount of risk they carried and the probability of improvement-achievability.
The SHELLO model formed the basis of the research , following which risk factors were selected from the six dimensions of the model. The six dimentions being the Pilot's core ability, interactions between pilots and other staff, pilots and organization, pilots and environment, pilots and software and finally pilots and hardware. The factors were chosen from the basis of the the above dimensions. Sources used for these factors included the SHELLO model following the classic framework of the SHELL model, the Human Factors Analysis and Classification System, the Accident Classification System, Boeing Accident Prevention strategies and other related studies . Following these basis, the authors identified 56 preliminary risk factors to be considered for the study.
Questionnaires were utilized by the authors to analyse the gravity of the risk factors. Utilizing different questionnaires through multiple stages, input was received from experts from various parts of the Aviation industries. Pilots, Airline operation employees in high positions, Taiwan Civil Aeronautics Administration employees (CAA) and members of the Aviation Safety Council (ASC) assisting with different stages of the process.
Through the study, the factors were narrowed down 25 factors for which; they were weighed in importance of each risk and the improvement-achievability of each factor.
As seen in the table below, we can see 10 matching factors from the top 13 ranked factors from both the pilot's survey and the management level experts. It can be seen what are the most important factors to aim for improving while also highlighting the difference between the consideration of the pilots and those at an organizational level.
|Rank for Pilot's Survey||Dimension||Risk Factor||Rank for Management Level Expert's Survey||Dimension||Risk Factor|
|1||Pilot's core ability||Situational awareness and attention||1||Pilot's core ability||Situational awareness and attention|
|2||Pilots and Environment||Runway/Taxiway marking and signs||2||Pilots and Environment||Runway/Taxiway marking and signs|
|3||Pilot's core ability||Fatigue/Incapacitation||3||Pilot's core ability||Safety attitude|
|3||Pilots and other staff||Communication between pilot and air traffic controller||4||Pilots and other staff||Communication between pilot and air traffic controller|
|3||Pilots and other staff||Instruction read back between pilot and air traffic controller||5||Pilot's core ability||Communication skills|
|6||Pilots and other staff||Pilot's crosscheck||6||Pilot's core ability||Fatigue/Incapacitation|
|6||Pilot's core ability||Operation deviation/negligence||7||Pilots and other staff||Pilot's crosscheck|
|6||Pilots and Organization||Pilot fatigue control||8||Pilots and other staff||Instruction read back between pilot and ATC|
|9||Pilot's core ability||Safety attitude||9||Pilots and Environment||Airport illumination|
|9||Pilot's core ability||Communication skills||10||Pilots and Hardware||Runway Incursion Prevention System|
|11||Pilots and other staff||Teamwork||11||Pilot's core ability||Decision making ability|
|11||Pilots and Environment||Airport Illumination||12||Pilot's core ability||Ability to deal with contingency or emergency|
|13||Pilot's core ability||Ability to deal with contingency or emergency||13||Pilots and Hardware||Runway Incursion Prevention System|
As seen, ten common risk factors were found.
- Situational awareness and attention
- Communication skills
- Safety attitude
- Ability to deal with contingency or emergency
- Communication between pilot and air traffic controller
- Pilot's crosscheck
- Instruction read back between pilot and air traffic control
- Airport illumination
- Runway/taxiway markings and signs
These ten factors are attributed with carrying the highest risk factor in runway incursions. However, it is also of importance to notice the difference between the pilot's survey and the management level expert survey. The experts focused on decision making ability, flight dynamics surface guidance system and runway incursion prevention system whereas the pilots concurred on operation deviation/negligence, teamwork and pilot fatigue control. It can be seen that the interaction between the pilot and hardware was considered to be a bigger issue from the expert level management standpoint whereas the focus of the pilots was on their core ability and the interaction between themselves and others.
The authors concluded that pilot human risk factors are of significant importance in the matter of runway incursions. Further on, the data fell in line with the US Federal Aviation Administration data; which shows that 55% runway incursion incidents and accidents between 2005 and 2007 were caused by pilot deviation, 29% by controller operational errors, and the remainder by vehicle or pedestrian deviations .
The aim of the study was to identify the risk factors and weigh them in the importance of improvement-achievability. The study did map out a graph utilizing the weight of the risk factor and the possibility of achieving improvement achievability. The authors did place these factors into four zones utilizing a risk analysis matrix. These four zones were based on the improvement achievablitiy ranking and their relative importance as deemed by the above surveys. The table below ranks them in order of their improvement-achievability ranking.
|1||Pilots and Organization||Completeness of Notice to Airmen|
|2||Pilots and Other Staff||Instruction read back between pilot and ATC|
|3||Pilots and Environment||Runway/Taxiway marking and signs|
|4||Pilot's core ability||Operation deviation/negligence|
|5||Pilots and Organization||Training System|
|6||Pilots and Organization||Safety management system|
|6||Pilots and Other Staff||Pilot's crosscheck|
|8||Pilot's core ability||Safety attitude|
|9||Pilots and Software||Familiarity with flight task before flight|
|10||Pilots and Software||Flight Crew Operating Manual|
|11||Pilot's core ability||Fatigue/Incapicatation|
|12||Pilots and Software||Explicit manual, rules and regulations|
|13||Pilots and Other Staff||Communication between pilot and air traffic controller|
|14||Pilots and Organization||Pilot fatigue control|
|15||Pilot's core ability||Situation awareness and attention|
|16||Pilot's core ability||Ability to deal with contingency or emergency|
|17||Pilots and Environment||Airport Illumination|
|18||Pilots and Hardware||Data displays|
|19||Pilots and Environment||Airport familiarity|
|20||Pilot and Hardware||Flight Dynamics Surface Guidance System|
|21||Pilot's core ability||Communication skills|
|22||Pilots and Hardware||Runway Incursion Prevention System|
|23||Pilots and Other Staff||Teamwork|
|24||Pilot's core ability||Decision-making ability|
|25||Pilots and Environment||Meteorology|
The four zones as based on the importance of the risk factor and improvement-achievability ranking are detailed as follows:
The study safely confirms the importance of human errors in runway incursions. The authors identified the key risk factors and also utilized a risk analysis matrix to categorize the factors into different zones. As a result, improvement strategies can be implemented accordingly.
The research was conducting from the basis of empirical analysis. Gathering data via questionnaires given to various members of the Taiwan aviation industry.
56 preliminary risk factors were selected on the basis of the SHELLO model, the Human Factors Analysis and Classification System, The Accident Classification System, Boeing Accident Prevention Strategies and other related studies . The questionnaires were given out to members from the Taiwan Civil Aeronautics Administration (CAA), an independent safety investigation authority, the Aviation Safety Council (ASC). The survey utilized the assistance of people in high management positions with over 15 years of experience. Four experts were selected from Taiwan airlines, two from Taiwan CAA and four from the ASC . 180 pilots of an international airline were also provided with a questionnaire for one of the stages.
Design & Variables
The study was divided by the authors into separate stages following the selection of the 56 preliminary factors.
- The first stage survey involved experts screening the 56 preliminary factors for the second-stage survey. The experts from the Taiwan CAA, the ASC, Taiwan airlines provided opinions on the factors. The fuzzy delphi method is utilized to narrow down the factors and to create a geometric mean for the six dimensions of the SHELLO model. 37 factors were selected at the end.
- The second stage consisted of providing primary factors to 180 pilots, with 112 being valid out of the 153 returned. They ranked each factor based on their judgement on a one to five Likert scale. The geometric means are calculated for each factor. Utilizing the Analytic Hierarchy Process (AHP) for all factors, usually not more than seven, to obtain 25 human risk factors. Based on expert opinions, the six dimensions are ranked to obtain overall ranking and importance of each dimension and risk factor.
- The third stage involved a new questionnaire being provided to the experts in the Taiwan CAA, the ASC and Taiwan Airlines. 14 questionnaires were returned from the 18 being provided. The participants were chosen from those holding high administrative positions among-st the various organizations. The 25 risk factors are analyzed for the improvement-achievability rating.
They were asked to be ranked in according to 5 different scores, from very low to very high (The five scores being indicative of numbers in increments of 20). Very high meaning the risk factor carries a higher achievability score. These scores are then turned into a triangular fuzzy numbers.
- Finally, the importance weighing of the factors from the second stage and improvement-achievability scores from the third stage are utilized to place them on a graph matching importance with improvement-achievability on the respective axis. The four quadrants give us the four zones that gives us the map for attempting improvement for the risk factors. The four zones being The top priority zone, the possible integration zone, the key challenge zone and the long-term promotion zone.
As seen, the variables were in the methods used and in the variety of aviation industry personnel selected for the study. Each person answered the questions according to their own opinion based on their experience and judgement.
Questionnaires were utilized for the empirical analysis.
- Fuzzy Delphi method being used to get results and create a geometric mean
- The Analytic Hierarchy Process (AHP) method used to get results for relative importance
The study provided different tables showing geometric means for the various stages of the study and providing a graph for the placement of each factor. This meta-analysis only provides rankings based on the data provided.
The study itself was focused on the Taiwan region, although the findings were found to be similar from the US Federal Aviation Administrative Data. As a result, the findings can be used to help implement improvements in both regions and across the globe as well.
- CHANG Yu-Hern & Kin-Meng WONG (2012). Human risk factors associated with runway incursions. Journal of Air Transport Management (ISSN 0969-6997), 2012, volume 24, pages 25-30.
Contributors to this page
Joben Nijjar (2013), Massey University, New Zealand.