StacksVerified U.S. regulatory reference

40 CFR §1030.25

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
For each airplane subject to this part, determine the airplane's nondimensional reference geometric factor (RGF) for the fuselage size of each airplane model, calculated as follows:
  1. (a)For an airplane with a single deck, determine the area of a surface (expressed in m∧2) bounded by the maximum width of the fuselage outer mold line projected to a flat plane parallel with the main deck floor and the forward and aft pressure bulkheads except for the crew cockpit zone.
  2. (b)For an airplane with more than one deck, determine the sum of the areas (expressed in m∧2) as follows:
    1. (1)The maximum width of the fuselage outer mold line, projected to a flat plane parallel with the main deck floor by the forward and aft pressure bulkheads except for any crew cockpit zone.
    2. (2)The maximum width of the fuselage outer mold line at or above each other deck floor, projected to a flat plane parallel with the additional deck floor by the forward and aft pressure bulkheads except for any crew cockpit zone.
  3. (c)Determine the non-dimensional RGF by dividing the area defined in paragraph (a) or (b) of this section by 1 m∧2
  4. (d)All measurements and calculations used to determine the RGF of an airplane must be made according to the procedures for determining RGF in Appendix 2 of ICAO Annex 16, Volume III (incorporated by reference in § 1030.110).