Rain is a product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It forms when separate drops of water fall to the Earth's surface from clouds. Not all rain reaches the surface; some evaporates while falling through dry air.| Classification | Rate of Precipitation |
| Very light rain | < 0.25 mm/hour |
| Light rain | Between 0.25 to 1.0 mm/hour |
| Moderate rain | Between 1.0 to 4.0 mm/hour |
| Heavy rain | Between 4.0 to 16.0 mm/hour |
| Very heavy rain | Between 16.0 to 50.0 mm/hour |
| Extreme rain | > 50.0 mm/hour |
The Centrisep® Engine Advanced Protection System (EAPS) separates water from the main engine airflow. Any remaining water that does enter the engine inlet is in the form of a harmless spray, which has no significant detrimental effect whatsoever on engine operation.
Although a Centrisep EAPS will greatly alleviate the hazard created by heavy rain, the helicopter’s flight manual instructions must strictly be adhered to at all times.