10.4 Ditching & Sea Survival Evacuation Procedures

Ditching & Sea Survival Evacuation Procedures

Ditching is defined as an intentional or forced emergency water landing of an aircraft. Whether executed in open ocean waters, coastal bays, or large river systems, ditching presents complex challenges requiring specialized cabin preparation, precise exit selection, slide-raft boarding, and open-sea survival tactics. NCAA cabin crew licensing exams rigorously evaluate candidate knowledge of ditching protocols and marine survival equipment.

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Pre-Ditching Cabin Preparation & Life Vest Donning Rules

In a planned ditching scenario, cabin crew execute cabin preparation steps similar to land emergencies, with critical variations tailored for marine survival.

The Strict Cabin Inflation Ban

During pre-ditching prep, cabin crew instruct all passengers to remove life vests from beneath their seats, slip the vests over their heads, pass the waist straps around their bodies, and buckle them tight.

However, cabin crew must deliver one of the most critical safety mandates in aviation:

ABSOLUTE RULE: NEVER INFLATE YOUR LIFE VEST INSIDE THE AIRCRAFT CABIN! INFLATE ONLY UPON EXITING THE DOORWAY / THRESHOLD.

Why Life Vests Must NEVER Be Inflated Inside Cabin

 [INFLATED INSIDE CABIN]                     [INFLATED AT DOORWAY THRESHOLD]
 +-----------------------------+             +-----------------------------+
 | 1. Traps occupant against   |             | 1. Full mobility through    |
 |    ceiling if water floods  |             |    aisles and door frame    |
 | 2. Blocks narrow exit doors |             | 2. Zero risk of trapping    |
 | 3. Tears on jagged torn metal|             | 3. Safe rapid evacuation    |
 +-----------------------------+             +-----------------------------+

Three Hazards of Premature Life Vest Inflation:

1. Ceiling Trapping / Drowning Hazard: If the aircraft fuselage ruptures and water floods the cabin rapidly, passengers wearing inflated life vests will automatically float upward to the ceiling. Because water fills from the floor up, passengers floating against the ceiling become trapped under water and drown, unable to dive down to reach floor-level exit openings.
2. Exit Obstruction: An inflated life vest doubles a passenger's torso volume, making it nearly impossible to squeeze through narrow overwing window exits or crowded door openings, creating a total blockage for trailing passengers.
3. Puncture and Tear Risk: Jagged torn metal edges inside a damaged airframe will instantly puncture and deflate inflated plastic vest chambers during movement.

Passenger Sharp Object Removal

Crew must instruct passengers to remove high-heeled shoes, sharp jewelry, tie clips, pens, dentures, and glasses, placing them in seat pockets or bags. High heels and sharp items will puncture inflatable slide-rafts and cause severe lacerations during ditching impact.

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Exit Selection & Slide-Raft Deployment in Water Landings

After the aircraft touches down on water and comes to a complete rest, exit assessment is performed with critical water-line considerations.

Waterline Exit Evaluation Rules

• Doors ABOVE the Waterline: Safe to open. Crew assess viewports; if the door sill is clear of high water, the door is opened in armed mode to deploy the slide-raft.
• Doors BELOW the Waterline: MUST REMAIN CLOSED AND LATCHED. If an aircraft rests at a nose-high or tail-down attitude, rear doors may be submerged. Opening a submerged door causes rapid water ingress, sinking the aircraft within seconds.
• Overwing Window Exits: Generally safe during ditching as wings provide floating buoyancy. Escape straps stored in overwing window frames are attached to wing fittings to provide handholds for evacuees.

Slide-Raft Deployment & Mooring Line Severing

On ocean-going commercial aircraft, escape slides are dual-purpose slide-rafts certified to float and accommodate 44 to 65 passengers (plus overload capacity).

Slide-Raft Deployment & Detachment Sequence
+-------------------------------------------------------------+
| 1. Open Door in Armed Mode (Slide-Raft Inflates on Water)   |
+-------------------------------------------------------------+
                               |
                               v
+-------------------------------------------------------------+
| 2. Execute 'Dry Boarding': Passengers Step Directly into Raft|
+-------------------------------------------------------------+
                               |
                               v
+-------------------------------------------------------------+
| 3. Raft Remains Tethered to Aircraft by Mooring Line       |
+-------------------------------------------------------------+
                               |
                               v
+-------------------------------------------------------------+
| 4. Locate Red Hook Knife on Slide-Raft Header               |
+-------------------------------------------------------------+
                               |
                               v
+-------------------------------------------------------------+
| 5. CUT MOORING LINE Before Sinking Aircraft Pulls Raft Under|
+-------------------------------------------------------------+

1. Dry Boarding: Passengers must step directly from the aircraft doorway threshold into the floating slide-raft without entering the water whenever possible. Keeping survivors dry is the single most effective defense against rapid ocean hypothermia.
2. Mooring Line Function: The slide-raft is attached to the aircraft doorway girt bar by a heavy-duty fabric Mooring Line (Tether). This line keeps the raft tethered to the aircraft during passenger loading so it does not drift away.
3. Cutting the Mooring Line: Once the slide-raft is loaded to capacity or the aircraft begins to sink, the mooring line must be severed immediately. A specialized Hook Knife is stored in a pouch on the raft header near the mooring line attachment point. A crew member or ABP pulls the hook knife and slashes the mooring line, freeing the raft from the aircraft.

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Sea Survival Tactics & Lifesaving Postures

Once clear of the sinking aircraft, survival depends on thermal management, raft organization, and rescue signaling.

Open Water Immersion Postures (Hypothermia Defense)

If survivors are forced to enter cold ocean water without a raft, body heat dissipates 25 times faster in water than in air. Survivors wearing life vests must immediately adopt standardized marine thermal postures:

Slide-Raft Equipment & Life Support Operations

After boarding the slide-raft, crew execute immediate survival tasks:

• Erect Canopy: Assemble canopy support poles and cover the raft with the weather canopy. The canopy protects survivors from hypothermia, cold salt spray, intense solar radiation, and heat stroke.
• Deploy Sea Anchor (Drogue): Throw the sea anchor into the water. The sea anchor acts as an underwater parachute, stabilizing the raft against wave capsizing and reducing drift speed so the raft remains near the last known aircraft GPS coordinates.
• Ration Fresh Water: Survival priority order: Protection -> Location -> Water -> Food. Do NOT distribute water within the first 24 hours unless victims are injured. STRICT WARNING: NEVER drink sea water or urine. The high sodium concentration in sea water causes severe renal failure, rapid dehydration, cellular breakdown, and death.

Signaling & Rescue Locating Equipment

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Operational Ditching Summary Matrix