What is the primary purpose of fuel sumps in an aircraft fuel system?

The primary purpose of fuel sumps in an aircraft fuel system is to collect and inspect for water and sediment in fuel tanks. Fuel sumps are strategically located in the lowest parts of the fuel tanks because water and sediment, being heavier than fuel, tend to settle at the bottom. Regularly checking these sumps allows for the detection of contaminants that could potentially harm the aircraft's fuel system or engine performance. By draining the sumps, pilots can ensure that only clean fuel is used, which is critical for the safe operation of the aircraft. This routine maintenance is an essential aspect of preventing fuel-related issues during flight.