MOC VTOL.2310(c) Ditching

(a)     If certification with ditching provisions is requested by the applicant, the aircraft should meet the following design criteria:

(1)     The design criteria defined for MOC VTOL.2310(b) Emergency Flotation

(2)     The aircraft should comply with the structural provisions for ditching, emergency flotation and overwater operations of MOC VTOL.2270

(3)     Each practicable design measure, compatible with the general characteristics of the aircraft, should be taken to minimise the probability that when ditching, the behaviour of the aircraft would cause immediate injury to the occupants or would make it impossible for them to escape.

(4)     The probable behaviour of the aircraft during ditching water entry should be shown to exhibit no unsafe characteristics.

(5)     For aircraft fitted with an emergency flotation system:

(i)      The aircraft should be shown to resist capsize⁽¹⁾, in the intended floating attitude, in the sea conditions selected by the applicant. The probability of capsizing in a 5-minute exposure to the sea conditions should be substantiated to be less than or equal to 3.0 % with a fully serviceable emergency flotation system and 30.0 % with the critical float compartment failed, with 95 % confidence.

(ii)     Allowances should be made for probable structural damage and leakage.

(iii)     An emergency flotation system that is stowed in a deflated condition during normal flight should be designed such that the effects of a water impact (i.e. crash) on the emergency flotation system are minimized.

(6)     For aircraft with watertight compartments, hull buoyancy and/or integrated buoyancy:

(i)      The aircraft should be shown to resist capsize⁽¹⁾, in the intended floating attitude, in the sea conditions selected by the applicant. The probability of capsizing in a 5-minute exposure to the sea conditions should be substantiated to be less than or equal to 3.0 % with fully functional buoyancy components, and 30.0 % with the functional loss of the critical buoyancy component, with 95 % confidence.

(ii)     Allowances should be made for probable structural damage and leakage.

(iii)     The buoyancy components should be designed such that the effects of a water impact (i.e. crash) on the buoyancy components are minimised.

(7)     Unless the effects of the collapse of external doors and windows are accounted for in the investigation of the probable behaviour of the aircraft during ditching and for the capsize resistance demonstration, the external doors and windows should be designed to withstand the probable maximum local pressures.

(8)     Additionally, for Category Enhanced: The aircraft design should incorporate appropriate post-capsize⁽¹⁾ survivability features to enable all passenger cabin occupants to safely egress the aircraft, taking into account the human breath hold capability.

(i)      One method of meeting this post-capsize survivability provision is to create stable floating attitudes which will create an air pocket in the passenger cabin. Passengers can utilise the air in the pocket for continued survival during the time needed for all to make their escape.

(ii)     The size and shape of the air pocket should be sufficient to accommodate all passengers. A minimum volume per passenger, in the form of an elliptical column of 70 cm x 50 cm (27 in. x 19 in.) and height of 30 cm (11 in.) relative to the static waterline should be established and demonstrated as fitting into the air pocket, including with the critical float compartment or buoyancy component failed.

(iii)     The air pocket should be accessible and immediately available without passengers needing to cross seat backs.

(iv)     Emergency breathing systems (EBSs) that are capable of being quickly deployed underwater do exist. This type of personal protective equipment (PPE) may provide a limited level of mitigation for the issues related to human breath hold capability, but it should not be considered alone as being sufficient to meet the post-capsize survivability provisions.

Note ⁽¹⁾: Capsize means full or partial capsize, i.e. inability to maintain the intended floating attitude.

(b)     CS 27 Amdt. 5 (or later): AMC 27.801 and AMC to CS 27.801(e) and CS 27.802(c) provide additional guidance.

(c)      If certification with ditching provisions is requested by the applicant, the flight manual should contain the substantiated sea conditions and any associated information relating to the certification obtained with ditching provisions.

(d)     The following MOCs 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