What defines "initially blocked" exits during an emergency situation?

In emergency situations, "initially blocked" exits refer to those that are not recommended for use due to a specific hazard, such as submersion in water. This essential understanding is vital for ensuring passenger safety. When an exit is submerged, attempting to use that exit may lead to drowning or other serious risks, making it a critical factor for the crew to communicate and manage during an emergency evacuation.

The other options do not accurately capture the concept of "initially blocked" exits. Exits that are inaccessible during turbulence may present challenges, but they do not specifically define the initial blockage relevant to an emergency. Similarly, exits that cannot be opened due to mechanical failure pertain more to operational issues rather than circumstances warranting an evacuation delay due to hazardous conditions. Finally, exits identified as occupied do not inherently indicate they are blocked; they may simply be in use, but not necessarily unsafe at the moment of an evacuation.