Expert interviews were used to supplement the findings of the literature investigation, particularly by providing insight into short-haul pilot/co-pilot fatigue in the South African context. Interviews served to reveal and clarify participants’ thoughts and opinions regarding the South African aviation context, and particularly their perspectives on what the major factors are that contribute to aircrew (pilot/co-pilot) fatigue. Any factors
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emerging from this process that are not reflected in the existing literature were then added to the developing model. Expert interviews are considered to be the most common and widely used sources of data in present-day qualitative research (Harrell and Bradley, 2009; Rabiee, 2004). According to Kaplowitz and Hoehn (2001), interviewing in research can provide a flexible, valuable and participatory method of obtaining detailed information on a topic based on participants’ experiences and perceptions.
3.4.2 Sampling
Sampling is defined as a method used to select individuals for inclusion in a study (Taherdoost, 2016). The participants selected to be interviewed included experts who specialize in the field of aviation and fatigue and who thus have theoretical knowledge and practical experience of the topic at hand – pilots from aviation institutions, fatigue specialists, and academics in appropriate fields of aviation research. For studies on single target groups and homogeneous populations it may be unnecessary to sample more than ten to twelve experts. Larger sample sizes are unlikely to change conclusions significantly and may instead lead to data saturation (Boddy, 2016). Participants were recruited through personal communication with people (face to face recruitment), via email, and by snowball sampling. Snowball sampling involves existing interviewees recommending other participants who they would consider to be suited to the study (Babbie, 2007).
Potential participants were screened after the completion of an online pre-screening self-assessment questionnaire (Appendix A1) compiled in Google Forms. This questionnaire was designed to determine the eligibility of participants based on the inclusion criteria outlined in Table 5 (those who did not match the criteria were not interviewed). A link was emailed to participants to allow them to complete the questionnaire online.
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Table 5: Inclusion criteria for selection of experts for interview.
SAMPLE SELECTION REASONS
Pilots/Co-pilots (with short-haul experience in Southern Africa)
Pilots and co-pilots were selected because of the value of their practical, lived experience of actually flying in short-haul operations. They can interpret the meaning of key events in the context of practical aviation, discuss their work-related challenges, and provide nuanced insight into their jobs.
Fatigue Specialists (FRMS - crew fatigue specialists or
academics)
FRMS - crew fatigue specialists were selected because of their expert scientific knowledge of fatigue-related safety risks in aviation. Examples of their varied professional repertoire include exploring the role of fatigue in incidents, providing training programmes for crew and schedulers, etc. Overall, they have extensive knowledge about fatigue in the aviation context and can provide expert insight into factors that they consider to be problematic for short-haul operations.
As Wilson (2002) noted, aviation is a high workload and stress-inducing occupation and pilot fatigue can be attributed to many underlying factors such as sleep loss or extended wakefulness, circadian disruption, workload, etc. Academics (scientific specialists) who focus on aviation research were selected for interview as they can provide detailed explanations and interpretations of their opinions, experiences and perceptions regarding fatigue, workload, sleep and circadian physiology in the aviation context. These interpretations are also distinguishing elements of interview research (Kuna, 2006).
3.4.3 Procedure of Expert Interviews
Interviews were conducted one-on-one and were guided by a set of questions prepared beforehand (Appendix A2). Questions were generally open-ended, therefore the interviews could be classified as “semi-structured”. The researcher was given the freedom to ask follow-up questions and to ask for clarification where necessary. In preparation for the real interviews, mock-up interviews were conducted to fine-tune the interview protocols, detect flaws in the questions, perfect questioning style, and in general to ensure that the researcher gained experience and confidence in conducting interviews. Sessions were designed to last approximately 30 to 45 minutes, under the assumption that experts would be more likely to participate in a shorter interview process.
Interviews were scheduled according to the availability of the interviewees, and the questions that were asked and the order in which they were asked remained the same for each interview session. The experts were interviewed either face to face at their
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respective workplaces, or via telephone or Zoom video communication when meetings in person were not possible. Zoom is a video communication software that provides audio-visual conferencing and collaboration capabilities. The software can be downloaded and used on any digital device and is an attractive alternative to the Skype application. Participants interviewed via Zoom were e-mailed a set of instructions prior to the interview session (Appendix A3) detailing how to connect to the software. All interviews were recorded in full, in writing and through digital recording of the audio stream (using the audio recording feature in Zoom, and independently on the researcher’s mobile phone). Permission to record was granted by each expert at the start of the interview session.
3.4.4 Expert Interview Data Analysis
The interview data were analysed using a thematic analysis approach inspired by the methods of Braun and Clarke (2006). These authors describe thematic analysis as a method for identifying, analysing, and reporting the themes (patterns) within a dataset. This process is also often described as “encoding qualitative information” (Boyatzis, 1998). The method is flexible enough to be applied in various theoretical frameworks and domains answering a diversity of research questions (Braun and Clarke, 2006). This particular approach has emerged from previous approaches to qualitative data analysis such as grounded theory, discourse analysis and narrative analysis (Braun and Clarke, 2006). It is able to report experiences, perceptions, meanings, and the realities experienced by participants (Braun and Clarke, 2006; Judger, 2016), and has been widely found to provide rich and detailed data (Braun and Clarke, 2006). The method is well suited to participatory research contexts, it is relatively straightforward and simple to learn, and it is accessible to researchers with little or no prior experience of interview research (Braun and Clarke, 2006).
The data analysis was preceded by a thorough familiarisation with the contents of the interviews. Audio recordings were transcribed and written into text using Microsoft Word 2016 (Judger, 2016; Morgan et al., 2013). The recordings were listened to several times to maximise the factual and linguistic accuracy of transcriptions (Braun and Clarke, 2006; Judger, 2016). In the first step of the analysis itself, the transcribed drafts were read several times to identify the key emergent factors, trends and patterns. Secondly the transcribed data were reduced to themes through a process of
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coding (Braun and Clarke, 2006). The QSR International’s NVivo 12 qualitative data analysis software, version 12.1.90 (NVIVO, n.d.), was utilised to facilitate this categorization. Coding involves identification of descriptive constructs and other features of the data that researchers deem to be particularly interesting and relevant to the aims of the study (Braun and Clarke, 2006). A numerical coding system is then applied to these identified elements of the data, according to their alignment with the research questions and aims (Braun and Clarke, 2006). Thirdly, the coded data were classified into potential themes. A theme is defined as a consistent pattern emerging from a dataset, that is relevant to the research questions and aims (Boyatzis, 1998; Judger, 2016). The transcribed interviews were screened for data relevant to each potential theme, and the themes were reviewed and refined by checking that the data content of each theme was consistent with the coded extracts and the entire data set (Braun and Clarke, 2006). This process was repeated until the emergent themes could be clearly defined and named (Braun and Clarke, 2006). Finally, reports were produced in which the main themes and findings were presented in a narrative format including direct citations of individual participants (Braun and Clarke, 2006).
3.4.5 Ethical Considerations
Ethical clearance for expert interviews was obtained from the Rhodes University Human Kinetics and Ergonomics ethics committee prior to participant recruitment and execution of the study (Appendix B1). The ethics application provided the following details: (1) a description of the concept, procedure and methodology of the research; (2) the information that would be provided to participants (instructions, informed consent, participation rights, etc.); (3) information about the potential benefits of participation in research studies such as this; (4) the subject characteristics and requirements of the study; (5) ways in which privacy of participants will be protected, how participation anonymity will be maintained, and a statement of the right to participation withdrawal. These latter guidelines and practices are followed to protect the institution and the researchers from potential legal implications that could arise from methods and behaviours carried out during the research. They are further elaborated below.