What percent of the total length of a flexible hose should be added for movement under pressure?

The correct value for the percent of the total length of a flexible hose that should be added for movement under pressure is indeed between 5 to 8 percent. This range accounts for the potential elongation and expansion of the hose material when fluid is pressurized within it.

When hoses are under pressure, they are subject to internal forces that can cause them to stretch or change shape. This physical response is particularly relevant for flexible hoses made from materials such as rubber or synthetic compounds, which possess elastic properties. If an incorrect length is used without this allowance, it could lead to tension that may cause damage to the hose or even system failure, resulting in leaks or breaks.

Understanding this aspect of flexible hose installation is critical in aviation maintenance where safety and reliability are paramount. By adhering to the recommended rise in length under pressure, technicians can ensure that hoses will not only fit properly but also function effectively under varied operating conditions. Such attention to detail is essential for maintaining the integrity of fuel, hydraulic, and pneumatic systems in aircraft.