Long Range Air Traffic Flow Management with Flight-Specific Flight Performance
Round 1
Reviewer 1 Report
This paper investigated the potential benefits of controlling 26 long-haul flights during cruise by applying speed adjustments and alternative routes to harmonize the number of aircraft in the approach sector of WSSS. The concept is sound, the paper is well-structured, and the case studies are well conducted. However, the following issues should be addressed or explained before the paper is approved for publication:
- “Specifically, the congestion within the purple highlighted period between 2.50 p.m. and 6.10 p.m. (highlighted as dotted circle number III) occurs due to the impact of 26 long-haul flights.” – line 258-260. Is it circle number II from Figure 5?
- This paper presents the data and optional routes in great detail. However, this paper is too brief in describing the methods and processes of optimization. The reviewer had one question. How to determine the best solution? Through Optimization? If so, please add more information about the Optimization algorithms or solvers.
- Applying speed adjustments and alternative routes could harmonize the number of aircraft in the approach sector while reducing fuel consumption. However, how can this method guarantee conflict-free speed adjustments or alternative routes during the en-route operation?
Overall, the paper is very well written, and I look forward to seeing it being published.
Author Response
Dear Reviewer 1, thank you for your comments. Please find attached our response.
With best wishes
Judith Rosenow
Author Response File: 
Author Response.pdf
Reviewer 2 Report
It's an interesting paper, which can be accepted provided that the authors appropriately address the following remarks.
Line 43. A full point is missing
Lines 43-50. Objectives of the paper are not clear. Please elaborate. Why “Therefore..” ? (line 49)
Line 88: “To the best of our knowledge…”. This sentence does not seem to be a consequence of what it is written before..”
Line 89: insides ?? Weather, why capital W
Line 91: ADS-B, I assume
Line 97-99: Why “the problem of minimizing the used capacity in the network” is the same as SSSP? This is not explained
Line 119: what does it mean that the “aircraft performance models represent the smallest unit”. ? Smallest w.r.t. what? Which kind of “unit” the author are referring to as?
Line 160-161. I’m not sure the paper objectives stated here are consistent with what written in lines 43-50. Please clarify.
Line 160. What is a realistic and Bligh-specific “potential” ??
Line 174. I suggest to divide section 3.1 in two or three subsections
Line 191. Please use a consistent notation (comma or point) to separate digits: 82.546 but 96,000 in line 189
Line 195. Please explain why the RDP algorithm is introduced, to which purpose
Line 196. “… separate the line…”. Which line the authors are referring to as?
Line 210-221: explain what a TTO and TDO are, and why you need to identify them
Line 212: the sentence “…, we assume TOD being the optimal and the latest TTO reference point.” is not clear to me.
Line 220: what is TOD 170NM, please clarify
Line 220: (left) not (right)
Line 266: “spent” instead of “spend”
Figure 6: are all flights considered, or only long-haul flights? Wouldn’t it be better to record the dwelling time just for the latter, as it could be different from short- and medium-haul flights because of the different aircraft characteristics?
Line 313: “.. fuel burn by the…”
Line 316: 2… equal to 1 if for flight i ….”
Equation (2). I’m not sure I understand this equation. How is C_t computed? It appears to be a problem parameter, hence known before running the optimisation model. Hence at each time instant t, the spare capacity does not depend on what happens at time t-1? In addition, which is the capacitated resource : the approach sector, which is referred to as “network” in line 321?
Line 332-334 and 339-341 are somehow similar.
Line 333: PID - acronym
Line 343 OEM - acronym
Line 344 “… 80% seat load factor of 83%, … “. Please clarify
Line 378-379. This sentence is not correct. The fact a problem is NP-hard or not does not depend on its size, but it’s an ‘internal’ characteristic. The Traveling Salesmen Problem is NP-hard. Of course, if we only have four nodes, there is no need to use heuristics approaches and the optimal solution is always found. Here it’s exactly the same thing. Please correct.
Author Response
Dear Reviewer 2,
thank you for your valuable comments. Please find attached our response.
Author Response File: Author Response.pdf
Reviewer 3 Report
Please see the attachment.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer 3,
thank you for your comments on our manuscript.
Please find attached our response.
With best wishes
Judith Rosenow
Author Response File: Author Response.pdf
