The airplane, even when damaged in an emergency landing, must protect each occupant against injury that would preclude egress when—

Properly using safety equipment and features provided for in the design;

The occupant experiences ultimate static inertia loads likely to occur in an emergency landing; and

Items of mass, including engines or auxiliary power units (APUs), within or aft of the cabin, that could injure an occupant, experience ultimate static inertia loads likely to occur in an emergency landing.

The emergency landing conditions specified in paragraph (a)(1) and (a)(2) of this section, must—

Include dynamic conditions that are likely to occur in an emergency landing; and

Not generate loads experienced by the occupants, which exceed established human injury criteria for human tolerance due to restraint or contact with objects in the airplane.

The airplane must provide protection for all occupants, accounting for likely flight, ground, and emergency landing conditions.

Each occupant protection system must perform its intended function and not create a hazard that could cause a secondary injury to an occupant. The occupant protection system must not prevent occupant egress or interfere with the operation of the airplane when not in use.

Each baggage and cargo compartment must—

Be designed for its maximum weight of contents and for the critical load distributions at the maximum load factors corresponding to the flight and ground load conditions determined under this part;

Have a means to prevent the contents of the compartment from becoming a hazard by impacting occupants or shifting; and

Protect any controls, wiring, lines, equipment, or accessories whose damage or failure would affect safe operations.