14 CFR Part 382 Nondiscrimination on the Basis of Disability in Air Travel (Air Carrier Access Act) (with amendments issued through May 2016)

(b) You may require a passenger with a disability in one of the following categories to travel with a safety assistant as a condition of being provided air transportation, if you determine that a safety assistant is essential for safety:

(1) A passenger traveling in a stretcher or incubator. The safety assistant for such a person must be capable of attending to the passenger's in-flight medical needs;

(2) A passenger who, because of a mental disability, is unable to comprehend or respond appropriately to safety instructions from carrier personnel, including the safety briefing required by 14 CFR 121.571(a)(3) and (a)(4) or 14 CFR 135.117(b) or the safety regulations of a foreign carrier's government, as applicable;

(3) A passenger with a mobility impairment so severe that the person is unable to physically assist in his or her own evacuation of the aircraft;

(4) A passenger who has both severe hearing and severe vision impairments, if the passenger cannot establish some means of communication with carrier personnel that is adequate both to permit transmission of the safety briefing required by 14 CFR 121.57(a)(3) and (a)(4), 14 CFR 135,117(b) or the safety regulations of a foreign carrier's government, as applicable, and to enable the passenger to assist in his or her own evacuation of the aircraft in the event of an emergency. You may require a passenger with severe hearing and vision impairment who wishes to travel without a safety assistant to notify you at least 48 hours in advance to provide this explanation. If the passenger fails to meet this notice requirement, however, you must still accommodate him or her to the extent practicable.