VTOL.2270 Emergency conditions
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(a) The aircraft, even when damaged in an emergency landing, must protect each occupant against injury that would preclude egress when:
(1) properly using safety equipment and features provided for in the design;
(2) the occupant experiences ultimate static inertia loads likely to occur in an emergency landing; and
(3) items of mass, including lift/thrust unit or auxiliary power units (APUs), within or adjacent to the cabin, that could injure an occupant, experience ultimate static inertia loads likely to occur in an emergency landing.
(b) The emergency landing conditions specified in VTOL.2270(a) must:
(1) include dynamic conditions that are likely to occur in an emergency landing; and
(2) 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 aircraft.
(c) The aircraft must provide protection for all occupants, accounting for likely flight, ground, and emergency landing conditions.
(d) 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 aircraft when not in use.
(e) Each baggage and cargo compartment must:
(1) be designed for its maximum loading and for the critical load distributions at the maximum load factors corresponding to the flight and ground load conditions determined under this Special Condition;
(2) have a means to prevent the contents of the compartment from becoming a hazard by impacting occupants or shifting;
(3) protect controls, wiring, lines, equipment, or accessories whose damage or failure would prevent continued safe flight and landing for Category Enhanced, or a controlled emergency landing for Category Basic; and
(4) be designed so that a fire does not preclude continued safe flight and landing for Category Enhanced, or a controlled emergency landing for Category Basic.
MOC VTOL.2270(a) and (c) Emergency landing conditions: General considerations
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This MOC provides a set of general design conditions that, when used in their entirety, are accepted to ensure adequate protection of occupants against injuries that would prevent egress in an emergency landing.
(a) CS 27.561(a) Amdt. 6 is accepted as a means of compliance.
(b) CS 27.561(b) Amdt. 6 is accepted as a means of compliance with the addition under subparagraph (3)(ii) of a 18 g ultimate inertial load factor in the forward direction for CTOL aircraft.
(d) CS 27.561(d) Amdt. 6 is accepted as a means of compliance replacing “fuel tanks” by “energy storage systems”.
(e) For CTOL, CS 23.561(d) Amdt. 4 is accepted as a means of compliance.
MOC VTOL.2270(b)(1) Emergency landing dynamic conditions
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(a) CS 27.562(a) Amdt. 6 is accepted as a means of compliance.
(b) CS 27.562(b) Amdt. 6 is accepted as a means of compliance under the following conditions:
(1) CS 27.562(b)(1) Amdt. 6 is accepted as a means of compliance, noting that the 30 g at seat attachment level was based upon the typical underfloor structure of a conventional rotorcraft. Therefore the 30 g is only valid if the structure underneath the seats has equal or better damping characteristics than a conventional rotorcraft. If specific design features are integrated, less than 30g at the seat may be acceptable based on analysis supported by tests
(2) CS 27.562(b)(2) Amdt. 6 is accepted as a means of compliance with the following addition: For CTOL peak floor deceleration should occur in not more than 0.05 seconds after impact and should reach a minimum of 26 g. For CTOL seat/restraint systems not being in the first row, peak deceleration should occur in not more than 0.06 seconds after impact and should reach a minimum of 21 g.
(3) CS 27.562(b)(3) Amdt. 6 is accepted as a means of compliance.
(c) CS 27.562(c) Amdt. 6 is accepted as a means of compliance.
(d) CS 27.562(d) Amdt. 6 is accepted as a means of compliance.
MOC VTOL.2270(c) Emergency Landing Conditions
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1. STRUCTURAL PROVISIONS: Ditching, Emergency Flotation and Limited Overwater Operation
VTOL capable aircraft will operate over different water environments, such as inland rivers and lakes, open seas and hostile sea areas. In order to be proportionate to the nature and risk associated to these different operational scenarios, three airworthiness categories are defined: limited overwater operations, emergency flotation and ditching. The air operations rules will specify the airworthiness category necessary for operations over water. The associated design criteria for these airworthiness categories have been developed following a tiered approach with a baseline set of conditions defined for limited overwater operations, additional criteria necessary for emergency flotation and further considerations added for ditching operations.
If certification with ditching provisions, emergency flotation provisions or limited over water operations is requested by the applicant, structural strength should meet the following design criteria.
If certification with emergency flotation or limited over water operations is requested, the loading conditions apply to the buoyancy components that are provided to meet VTOL.2310 and VTOL.2270(c) respectively, and their attachments to the aircraft. Buoyancy components may consist of flotation units of an emergency flotation system (floats), watertight compartments, hull buoyancy, integrated buoyancy or a combination of these.
If certification with ditching provisions is requested, the loading conditions apply to all parts of the aircraft.
(a) Landing conditions:
(1) The conditions considered should be those resulting from an emergency landing into calm water.
(2) Additionally, if certification with ditching provisions or emergency flotation provisions is requested by the applicant, the conditions considered should also be those resulting from an emergency landing into the most severe sea conditions for which certification is requested by the applicant
(3) Unless other rational landing conditions acceptable to the Agency are defined, the following entry conditions apply: a forward ground speed not less than 15.4 m/s (30 knots), and a vertical speed not less than 1.5 m/s (5 ft/s), in likely pitch, roll and yaw attitudes, for each aircraft configuration.
(b) Loads:
(1) Aircraft with floats fixed or intended to be deployed before water contact: CS 27.563(b)(1) Amdt. 5 (or later) is accepted as a means of compliance.
(2) Aircraft with floats intended to be deployed after initial water contact: CS 27.563(b)(2) Amdt. 5 (or later) is accepted as a means of compliance.
(3) Aircraft with watertight compartments, hull buoyancy and/or integrated buoyancy: The loads to be considered are those resulting from the aircraft entering the water, in the conditions defined in (a), and in accordance with flight manual procedures.
(c) Procedures:
(1) The buoyancy components and their attachment structure should be substantiated for limit and ultimate loads, as specified in (b).
(2) A review of likely damages to the structure in the vicinity of the buoyancy components should be carried out, including consideration of splintering and sharp edges. The risk from such damage of puncture or improper functioning of the buoyancy components during water entry and flotation should be minimised.
(3) Additionally if certification for ditching is requested by the applicant, any aircraft structure the failure of which would impair flotation, capsize resistance or cabin egress should be substantiated for limit and ultimate ditching loads, unless the effects of these failures are accounted for in the investigation of probable behaviour of the aircraft during water entry, flotation, and the capsize resistance demonstrations.
CS 27 Amdt. 5 (or later): AMC 27.563 provides guidance.
2. Limited Overwater Operations
(a) If certification for only limited overwater operations is requested by the applicant, the aircraft should meet the design criteria defined for MOC VTOL.2310(b) Emergency Flotation, with the exception that capsize resistance of (a)(1)(ii) and (a)(2)(ii) need not be demonstrated.
(b) The following MOC VTOL paragraphs are also applicable:
(1) MOC VTOL.2315(a) Means of egress and emergency exits
(2) MOC VTOL.2430(a)(6) Energy retention capability in an emergency landing
(3) MOC VTOL.2535 Safety Equipment
(4) MOC VTOL.2605(c) Information related to safety equipment
(5) MOC VTOL.2610 Instrument markings, control markings and placard
NOTE: The MOC VTOL applicable to Emergency Flotation and Ditching operations are listed in MOC VTOL.2310(b) and MOC VTOL.2310(c) respectively.
MOC VTOL.2270(e) Cargo and baggage compartments
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The following provisions provide a set of design criteria that, when used in their entirety, are accepted to ensure compliance of the baggage compartment design with VTOL.2270(e):
(a) CS 27.787 Amdt. 6 is accepted as a means of compliance.
(b) CS 27.855(b) Amdt. 6 is accepted as a means of compliance.
(c) For CTOL, in addition to (a) and (b), CS 23.787 Amdt. 4 is accepted as a means of compliance