Development and Evaluation of Single Pilot Operations with the Human-Centered Design Approach
Round 1
Reviewer 1 Report
The authors introduced the problem by discussing the movement toward SPOs with accurate facts, data, and described the remaining gaps in the current body of literature. The topic is relevant, engaging, and provides direction for researchers in the area. The methodology followed clear guidance on developing a process toward data collection. The sample size is somewhat limited and the authors may want to add justification and validity of the size. The figures were often times difficult to read even when I zoomed in. The editors may want to suggest changes based on the journal;s best practices. The tables were mostly easy to follow except for table 2. There are areas for improvement.
In the conclusion, the authors should refer to previous research and make connections as well as explicitly state limitations and future research. Regarding writing style and grammar, there were many instances in which the authors used the present tense to discuss past research activities. A thorough check for grammar errors should be conducted. There were also a few misspellings. E.g., line 121 has both tense and spelling errors.
Overall, this manuscript should be published with minor to moderate revisions.
Author Response
We would like to thank you for your careful reading, helpful comments, and constructive suggestions, which has significantly improved the presentation of our manuscript. Please see the attachment our reply.
Author Response File: 
Author Response.docx
Reviewer 2 Report
121. These recordings are transacribed into six catagories of excel files as 121
flows: [typos.. three in one sentence: transcribed, categories, and “as follows”]
137. Whole session was recorded for later analysis [add “The” to start]
149. However, Hierarchical Task Analysis (HTA) [39] is an extension of the traditional task analysis. [Remove “however”]
190. Work Domain Analysis (WDA) was a common component of CognitiveWork Analysis (CWA) which was used to identify the purposes of system and the functions to achieve 19hose purposes. WDA typically used Abstraction Hierarchy (AH) to represent the purposes,constraints and functions of work domain [41,42]. [In general, I would look through the entire paper to use present tense where the statement is something that is currently true.]
208. Considering the powerful capabilities of AH to identify functional requirements and perform function allocation, this paper adopted for the first time the combination of HTA and AH methods to extend to the future SPO model. [1. AH doesn’t “perform” FA, it can be used to represent different FAs; 2. I would caution against saying “first time” for anything.. it is unnecessary, overly self-promoting, and essentially unverifiable .. in fact, one of the references you cite is same approach for this purpose.. not identical, but along the same lines.. enough that this is ‘first’ only as much as any other paper provides an advance over other work. ]
Stanton, N.A.; Harris, D.; Starr, A. Modelling and Analysis of Single Pilot Operations in Commercial Aviation. In Proceedings of the Proceedings of the International Conference on Human-Computer Interaction in Aerospace; Association for Computing Machinery: New York, NY, USA, 2014; HCI-Aero ’14.
Validation – ideally this is done by a set of SMEs who were not those that were involved in development.
HITL/HPM – I’m not sure why these are mentioned, They seem to not be used. As such, recommend they are in introduction as prior approaches, not methods section. Scrub section 2 for anything that the current authors did not do, and put that clearly in the introduction and/or reference in comparison to this paper’s results in conclusion as to similarities, differences.
213. The obtained AH Model could identify the functional requirements for the transition to SPO, which in turn led to corresponding technical assumptions. Introducing technical assumptions into the current AH model implemented the reallocation of functions in the current aviation system to agents of the SPO conceptual framework, and function allocation results were used to guide the development of future SPO model. [The AH Model did not lead to technical assumptions, it was used to represent the application of a FA strategy – which then implies technological complementation assumptions]
403. Given the above analysis, this paper proposes the following function assumptions:
[I would say that these are technological complements to as they are first described as the ‘things’ and later described in terms of the functions they serve – i.e., if you were to focus on the functions, you would indicate which of the piloting functions are relieved by these technologies now performing the associated activities. It would likely be worth noting that these technologies would not provide complete replacement of the related piloting activities.. as there would likely be residual monitoring functions, and now new monitoring of the systems themselves.
Section 3.4 – this is interesting, and I do understand that the main point is a comparison of the conditions you state – but I wonder if there is any other context associated with this type of analysis to characterize these options wrt other analyzed situations.. comparable workload/connectiveness/robustness/safety? You talk about this wrt the individual nodes, but there seems to be similar interpretation for the network-level analysis. What does it mean to have these parameters be high/low? For each, maybe an indication of the valence that provides an advantage?
Appendix B – please provide a page that talks through an example of how to interpret the diagram and includes the legends, acronyms, organization – i.e., how are concurrent v. sequential actions depicted?
Author Response
We would like to thank you for your careful reading, helpful comments, and constructive suggestions, which has significantly improved the presentation of our manuscript. Please see the attachment our reply.
Author Response File: Author Response.docx
