Have you ever noticed a distinct decrease in the noise level caused by airflow in the cockpit of an aircraft when the cabin pressure is approximately 2.1 pounds per square inch (psi) during ascent? Surprisingly, the airflow noise level remains the same and unchanged until the aircraft starts its descent and the cabin pressure decreases back to 2.1 psi, which then causes the airflow noise level to increase again.
To address this issue, a modification has been designed specifically for the A320 aircraft.
This modification serves two purposes – it prevents water from entering the cockpit area and also stops water from flowing under the aircraft’s floor into the avionics bay. The solution involves the installation of a fluid collector grid, along with an associated water grid rack and drainage system at the cockpit door. These drains allow any accumulated water or condensation to escape, thus avoiding potential corrosion issues.
To facilitate the drainage process, a drainage pipe has been incorporated into the grid system. This ensures that any fluid that enters the grid is carried to the lowest point in the forward fuselage. The noise that is audible in the cockpit is a result of the drain valves located in the forward structure of the nose fuselage, which are connected to the collector grid.
During the pressurization of the cabin, these valves are set to close when the cabin’s differential pressure reaches 2 psi. This closure prevents the loss of cabin pressure. However, as the cabin pressure decreases below the preset value, the valves open under the tension of springs. This opening allows any water that has collected in the collector grid to drain away, preventing any potential issues arising from water accumulation.
In summary, the modification in the A320 aircraft aims to address the noise caused by airflow in the cockpit during ascent and descent. By installing a collector grid and associated drainage system, water and condensation can be effectively drained away, preventing corrosion and ensuring a more comfortable and safe flight experience.
Author – Milad Mohammadi ( Airline Pilot A320 )
