MOC VTOL.2270(c) Emergency Landing Conditions

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.

(4)     Total lift may be assumed to act through the centre of gravity during water entry. This lift should not exceed two-thirds of the design maximum weight.

(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.