Definition
A flexible tube used to carry fluids or gases between components in an aircraft system. Aviation hoses are constructed in layers — typically an inner tube to contain the fluid, a reinforcement layer (such as braided steel, fiber, or wire) to handle pressure, and an outer cover to protect against abrasion, heat, and chemicals. Hoses are rated for specific pressures, temperatures, and fluids (fuel, oil, hydraulic fluid, air, etc.) and must be matched to the system in which they are installed.
Plain English
A flexible tube that carries liquid or gas from one part of the aircraft to another. It bends so it can connect parts that move or sit at different angles, and it is built strong enough to handle the pressure and the type of fluid running through it.
Context Anchor
Seen during aircraft inspections, engine compartment checks, brake system maintenance, and fuel or oil system discussions.
Derivation
From Middle Dutch 'hose,' originally meaning a covering for the leg (a stocking or sleeve). The sense of a flexible tube came later, drawing on the same idea of a long, hollow, flexible covering. Knowing this helps explain why a hose is fundamentally a flexible sleeve carrying something inside it, as opposed to a rigid pipe or tube.
Why Pilots Care
Hoses are wear items. A cracked, swollen, chafed, or leaking hose can lead to fuel leaks, loss of hydraulic pressure, oil starvation, or brake failure. Pilots check hoses visually during preflight, and any sign of seepage, bulging, or damage is a reason to ground the aircraft until maintenance addresses it.
Intuition Check
Do not think of an aircraft hose as just a simple garden hose. In aviation, a hose must be the correct type, condition, and rating for what it carries and where it is installed.
Example Sentence 1
On preflight, the pilot noticed a small wet spot near the engine and traced it to a weeping fuel hose, which grounded the aircraft until a mechanic could replace it.
Example Sentence 2
Inspect hydraulic hoses for cracks during every preflight check.