Drain Mast

Drain Mast

A drain mast is a small but essential external component found on most transport-category aircraft. It functions as a discharge point for the controlled expulsion of fluids such as condensation, fuel residue, potable water runoff, and lavatory waste from various onboard systems.

Typically located on the aircraft's lower fuselage or belly, the drain mast helps maintain system hygiene, operational integrity, and safety. Some masts are equipped with built-in heating elements to prevent fluid icing, especially at altitude or in cold ground conditions.

Proper drainage is critical for:

• Preventing corrosion of surrounding airframe surfaces
• Avoiding ice accumulation that could disrupt airflow or damage components
• Maintaining sanitary and safe evacuation of waste fluids

While visually minor, the drain mast plays an important role in long-term aircraft health and system function. It is inspected regularly during preflight and maintenance checks for leaks, blockage, or structural wear.

Source

Curated for AviationSafetyX by Skye and Albert — where even the smallest parts have legendary purpose.