Aviation Boatswain’s Mate – Fuels (ABF) Practice Test 2026 - Free ABF Practice Questions and Study Guide

The important idea is keeping the suction pickup submerged so the pump maintains prime and won’t draw in air. Extending the service tank suction tailpipe 24 inches below the bottom of the tank ensures the end of the suction line stays well under the liquid surface during normal operation, even when the aircraft tilts or the fuel level changes. This depth helps prevent air ingestion and loss of flow, which can happen if the end gets too close to the surface or rises above it during movement. If the tailpipe were shorter, air could be drawn in more easily; if it were longer, there’d be a greater risk of drawing sediment as the tank nears empty. Twenty-four inches provides a safe, practical balance.