Division 4.2.3 Instrumentation

Any instruments shall be installed in such a manner as to minimise their effects on the aerodynamic characteristics of the vehicle.

If the effect of the installed instrument on (C_D × A_f) is expected to be greater than 0,015 m², the vehicle with and without the instrument shall be measured in a wind tunnel fulfilling the criterion in paragraph 3.2. of this Sub-Annex. The corresponding difference shall be subtracted from f₂. At the request of the manufacturer, and with approval of the approval authority, the determined value may be used for similar vehicles where the influence of the equipment is expected to be the same.