{
  "url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.7/division-2.7.13/division-3",
  "json_url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.7/division-2.7.13/division-3.json",
  "legislation": "eudr/2015/996",
  "legislation_title": "Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-directive-2015-996",
  "path": "annex/division/ASSESSMENT/division/2/division/2.7/division/2.7.13/division/3",
  "kind": "division",
  "number": null,
  "heading": "Segmentation of the takeoff ground roll",
  "text": "When taking off, as an aircraft accelerates between the point of brake release (alternatively termed Start-of-Roll SOR) and the point of lift-off, speed changes dramatically over a distance of 1 500 to 2 500 m, from zero to between around 80 and 100 m/s.\nThe takeoff roll is thus divided into segments with variable lengths over each of which the aircraft speed changes by specific increment ΔV of no more than 10 m/s (about 20 kt). Although it actually varies during the takeoff roll, an assumption of constant acceleration is adequate for this purpose. In this case, for the takeoff phase, V1 is initial speed, V2 is the takeoff speed, nTO is the number of takeoff segment and sTO is the equivalent takeoff distance. For equivalent takeoff distance sTO (see Appendix B), start speed V1 and takeoff speed V2 the number nTO of segments for the ground roll is\nnTO = int(1 + (V2 – V1 )/10)\n(2.7.10)\nand hence the change of velocity along a segment is\nΔV = (V2 – V1)/nTO\n(2.7.11)\nand the time Δt on each segment is (constant acceleration assumed)\nΔt = 2 × s TO V 2 + V 1 × n TO\n(2.7.12)\nThe length sTO,k of segment k (1 ≤ k ≤ nTO) of the takeoff roll is then:\ns TO,k = k − 0,5 × ΔV × Δt = 2 k − 1 × s TO n 2 TO\n(2.7.13)\nSimilarly to the speed changes, the aircraft thrust changes over each segment by a constant increment ΔP, calculated as\nΔP = (PTO – Pinit)/nTO\n(2.7.14)\nwhere PTO and Pinit respectively designate the aircraft thrust at the point of lift-off and the aircraft thrust at the start of takeoff roll.\nThe use of this constant thrust increment (instead of using the quadratic form (equation (2.7.8)) aims at being consistent with the linear relationship between thrust and speed in the case of jet-engine aircraft (eq. B-1).",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eudr/2015/996/annex/division/ASSESSMENT/division/2/division/2.7/division/2.7.13/division/3",
    "retrieved_at": "2026-11-01T15:21:38.862218+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}