Where are the INS accelerometers mounted?

• A. On the airframe at random locations
• B. On a stable platform
• C. In the cockpit overhead panel
• D. On the tail rotor

Answer: (B)

Stability of the mounting platform is essential for INS accelerometers. An INS measures linear acceleration along three axes to determine velocity and position, and it must reference a fixed, rigid frame that doesn’t move with the aircraft or suffer from vibration. A stable platform—typically a rigid, vibration-damped, gimbal-stabilized structure—isolates the sensors from airframe vibrations and flex, keeping their orientation constant relative to inertial space. This allows the accelerometers to register true accelerations, which are then integrated to compute motion. Placing sensors on random airframe locations, in the cockpit, or on the tail rotor would subject them to varying vibrations or rotor motion, corrupting the readings. Therefore, they are mounted on a stable platform.