FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

The air in a hydraulic accumulator is prevented from entering the fluid system by physically separating the air chamber from the oil chamber. This separation ensures that only hydraulic fluid is allowed to enter the system, while the air is contained separately.

Option A (By a one-way valve) is incorrect because a one-way valve allows fluid to flow in only one direction and does not provide a complete physical separation between the air and the fluid system.

Option B (By cooling the air) is incorrect as cooling the air does not prevent it from entering the fluid system. It may help in reducing the temperature of the air in the accumulator but does not address the issue of air entering the fluid system.

Option D (By maintaining high pressure) is also incorrect because simply maintaining high pressure in the accumulator does not prevent the air from entering the fluid system. The physical separation of the air chamber from the oil chamber is essential to ensure the integrity of the hydraulic system.