How many crew life vests are installed in the AFT FA station of the ERJ 175?

The correct answer is that two crew life vests are installed in the AFT Flight Attendant station of the ERJ 175. This design is based on regulatory requirements that ensure adequate safety equipment is available for crew during emergencies. The presence of two life vests allows for one for each flight attendant stationed in that area, enhancing overall safety and preparedness for situations that may require evacuation over water.

In the context of airline safety regulations, it's critical to provide sufficient life vests for the crew who may need to assist passengers in an emergency situation. The choice of providing two life vests is a balance between safety and the practical space constraints within the aircraft, ensuring that flight attendants can quickly access life vests when needed.