Safety Risk Modelling and Assessment of Civil Unmanned Aircraft System Operations: A Comprehensive Review
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors,
Thank you for the opportunity to read your paper. I found it interesting due to the field addressed - connecting the UAS and safety domains.
Nevertheless, despite the value the risk methodology review brings to the domain I would expect more concrete, valuable conclusions indicating on the optimal approach and allowing for making progress toward definition of UAS tailored risks approach. In the paper the reader is left with description of various risk and safety related methodologies without any conclusions regarding (optimal) application. I find it as too few to justify publication.
I look forward to seeing the study contributing to the identification of optimal processes addressing safety and risk management issues in UAS domain.
Best Regards
Author Response
Dear reviewer
Based on your valuable comments, we have finished our revision process. Please see the attachment.
Thank you for your constructive works.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsReview report for the manuscript of “Safety Risk Modelling and Assessment of Civil Unmanned Aircraft System Operations: A Comprehensive Review”
The above manuscript has provided a comprehensive and systematic review of civil UAV’s safety risk modelling and assessment which will be benefit to researchers, regulators and policymakers in the field.
Some comments and suggestions for a minor revision, mostly are editorial:
Page 3, line 85: inset a ‘ before UAV’
Figure 2 (b): Sort the legend order based on the vertical sequence of the data, that is, yellow, red, blue and green, just like what (a) has done which makes an easy reading of the plot.
Table 1: in the final print-set version, please make sure the table will not be split over the pages which makes it hard to read. In addition, add a thin horizontal line in between each citation to make the reading easier. Same to Table B1 to B11 in the appendix.
Page 4, Line 132-136: May be add some description to the Appendices, which occupies 5.5 pages, weighted about 20% of the manuscript.
Page 5, Line 154: “the operational risks of UAS are controlled above acceptable levels”. – In the risk terminology, we normally want to control the risk to be below the acceptable level.
Page 7, Line 195: Make sure the Figure 5 caption will go with the figure in the same page in final print-out version.
Page 7, Line 237: “TLS” – this is the 1st time to cite so the full name (target level of safety) should be spelt out here.
Page 9, Line 300: “cause factors” may be replaced by “causal factors”.
Page 15, Line 624-625: “Although incident investigation authorities have published reports on incidents and 624 accidents involving certain statistics [108].” – This sentence may have grammar issues. I think the next sentence is part of this one, so the full stop after [108] may be changed to a comma.
Page 16, Line 683: “Second, several authors may utilize other keywords instead …” – “several” maybe replaced by “other”, and therefore “other keywords” may be replaced by “different keywords” if you don’t want two “other” in the same sentence.
Lastly, because large number of abbreviations have been use in this manuscript, as always in the aviation case, it will help readers to have a notation list given in the manuscript such as in the appendix.
Comments on the Quality of English LanguageComments attached above.
Author Response
Dear reviewer
Based on your valuable comments, we have finished our revision process. Please see the attachment.
Thank you for your constructive works.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThank you for the opportunity to review this manuscript. My comments are below, in the order I came across them rather than in order of importance:
1. Line 38 - why the et al? Did you mean et cetera?
2. Line 41 - is it worthwhile inserting a degree of caution here - a 2019 article is used but a lot of the implementation of last mile delivery by drone has not eventuated.
3. Please be careful about the use of legislation as opposed to regulation. Legislation is something passed by a legislature (e.g., by Parliament, or Congress/Senate). Regulations are rules made under that legislation (e.g., the Civil Aviation Rules or Federal Aviation Rules). This is an important distinction and each should be used correctly.
4. Sense and Avoid is a perfectly fine term, however, I wonder if Detect and Avoid (DAA) would be better. I think you need to explain what that is opposition to, which is See and Avoid (also shortened to SAA). That is how aircraft are separated now in uncontrolled airspace, so what is needed is a move from See and Avoid to Detect and Avoid to support UTM (according to that paper). This has been discussed also in relation to enabling BVLOS applications for drones.
5. Only JARUS SORA, EASA, and FAA regulations have been covered. However, there are similarities amongst regulations around the world, though perhaps don't fall strictly within low, medium, and high risk. Some commentary to that effect would be helpful. It is understandable why the focus on those examples as they are more formalised risk assessments, however, even judgements on what rules are needed for safety have their basis in some idea of risk modelling (even if less formalised). A couple relevant sources might be: https://doi.org/10.1016/j.tranpol.2022.06.006 (particularly Table 2) and https://doi.org/10.1111/tran.12448 among others.
6. The Flight Safety Foundation's BARS for RPAS standards use a bow-tie model as there basis, but are less formalised in their assessment. This model doesn't appear to be mentioned anywhere, despite its use in industry (particularly organisations engaged with oil, gas, and mining).
7. In general, at the end of the paper, I was still left questioning how the 120 papers were selected. I know it is written as a review, but it should still be replicable and have clear inclusion and exclusion criteria. It is clear a comprehensive review has taken place and I see much value in the paper, however, the approach/method could be better elucidated to allow for replication in the future and validation of the research.
Author Response
Dear reviewer
Based on your valuable comments, we have finished our revision process. Please see the attachment.
Thank you for your constructive works.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsPlease see attached.
Comments for author File: Comments.pdf
Author Response
Dear reviewer
Based on your valuable comments, we have finished our revision process. Please see the attachment.
Thank you for your constructive works.
Author Response File: Author Response.pdf
