A cabin full of strangers is a safety system in its own right: in an evacuation, the passengers are the workforce. The rules in this lesson all serve that one idea. Who needs special care and where they may sit, who may hold the exit rows, what everyone must be told, what may happen around the aircraft while they board, and how the cabin is locked down before the wheels move. The recurring actors are the operator, who establishes procedures, and the commander, who must be satisfied before anything happens.
Special categories of passengers
Persons requiring special conditions, assistance or devices when carried on a flight are special categories of passengers (SCPs), and the rule names at least three groups:
Persons with reduced mobility (PRMs) — anyone whose mobility is reduced by physical disability, sensory or locomotory, permanent or temporary, by intellectual disability or impairment, by any other cause of disability, or by age.
Infants and unaccompanied children — including a child under 12 separated from their accompanying adult in another cabin class.
Deportees, inadmissible passengers and prisoners in custody — carried, but under conditions, and the commander has the right to refuse their transportation if carriage would increase the risk to the aircraft or its occupants.
Three rules frame every SCP flight, two binding and one from the acceptable means of compliance. They are carried under conditions that ensure safety, according to procedures established by the operator. Their number should not exceed the number of passengers capable of assisting them in an emergency, a capable passenger being one with no competing role, an adult travelling alone rather than a parent with young children. And the commander is notified in advance whenever SCPs are to be carried. The commander's wider list of people-related powers is the next lesson's subject.
Seating the cabin
The seating rule is written from the evacuation backwards: passengers are seated where, if an evacuation is required, they are able to assist and not hinder the evacuation of the aircraft. At an emergency-exit row not staffed by a cabin crew member, a passenger should occupy a seat on each side during taxi, take-off and landing, unless passenger numbers or mass and balance make that impracticable, and those occupants must appear reasonably fit, strong, able and willing to assist a rapid evacuation after an appropriate briefing. Direct access has a precise meaning: a seat from which a passenger can proceed directly to the exit without entering an aisle or passing around an obstruction.
SCPs must not be allocated, nor occupy, seats with direct access to emergency exits, nor any seat where they could impede the crew, obstruct access to emergency equipment or impede evacuation. The excluded list for exit seats is broader still:
Obvious disability — physical or mental, to the extent that moving quickly on request would be difficult.
Substantially blind or deaf — to the extent that printed or spoken instructions might not be readily taken in.
The frail — by age or sickness, and those whose size would slow them through the adjacent exit.
Children and infants — accompanied or not.
Deportees, inadmissible passengers and prisoners — and passengers travelling with animals.