Review of manuscript DOM-21-0395-OP

This is an interesting original observational study addressing an important practical issue. The manuscript deserves several modifications in order to improve its quality and readibility. More particularly, the section related to the Results needs to be rewritten, as it currently does not highlight the main findings.

Abstract :
- the objective of the study is not stated
- please specify capillary blood glucose
- subgroups are ill-defined (we understand that these are categories of glucose ranges, and not subgroups of pilots)
- conclusion : it is not appropriate (but it supports the view) to state that the traffic light system reduced the frequency and severity of problems, as this was an observational, uncontrolled study. Rather, the authors should have focused on the impact of the protocol rules demanding actions to be taken at critical levels.

Methods :
- the objective of the study is not stated
- was the study prospective or retrospective ? please mention that this was an observational, uncontrolled, retrospective study
- how were the 49 pilots selected for this study (no study chart)

Results :
- please describe the distribution of type 1 and type 2 diabetes, and different insulin treatment schemes (pumps ?)
- page 10, line 6 : what are the four subgroups ?
- there are no report of Clarke or Gold scores
- a description of all pilots according to the parameters used in Table 1 would be useful
- from Figure 1-A, it seems that one pilot experiencing a low red value at time 0 did take off : this is worth a comment
- figure 3 : can the difference in rate of fall be related to the phenotype of the pilot (duration of disease, insulin requirements, etc)

Discussion :

We agreed upon the fact that this paper is somehow outdated, as the availability of continuous glucose monitoring has eclipsed the impact of capillary blood glucose measurements.