14 C.F.R. § 252.9 Ventilation systems.
Title 14 - Aeronautics and Space
Air carriers shall prohibit smoking whenever the ventilation system is not fully functioning. Fully functioning for this purpose means operating so as to provide the level and quality of ventilation specified and designed by the manufacturer for the number of persons currently in the passenger compartment.
Title 14: Aeronautics and Space
PART 252—SMOKING ABOARD AIRCRAFT
§ 252.9 Ventilation systems.
