Accelerometer in Aircraft Instruments

How Accelerometers Work in Aircraft

Accelerometers in aviation detect acceleration by measuring the displacement of a small mass inside the sensor. In traditional mechanical designs, this mass is suspended on a spring, and its movement under acceleration is shown on a calibrated scale, often as load factor (G units). More advanced designs use electromagnetic feedback for higher accuracy, where the position of the mass is detected electronically and corrected by a feedback loop, with the required current indicating the acceleration.

MEMS Accelerometers and Modern Systems

Micro Electro Mechanical Systems (MEMS) accelerometers have revolutionized aviation by miniaturizing the sensor while maintaining precision. These are integrated into IRS and other avionics, arranged orthogonally (at right angles) to sense acceleration in all three axes: longitudinal, lateral, and vertical. Each accelerometer measures acceleration on a single axis, and together they provide a complete picture of the aircraft's movement.

Applications in Flight Instruments

Accelerometer data is vital for multiple aircraft systems:

• IRS for navigation and attitude reference
• Autopilot and flight director for smooth and accurate control
• Yaw damper to counteract Dutch roll
• Autobrake systems for optimized braking
• Flight data recorders for accident investigation

Accelerometers differ from gyroscopes: accelerometers measure linear acceleration, while gyroscopes detect rotational movement (roll, pitch, yaw). Both are essential inertial sensors in aviation.

Accelerometer vs Gyroscope

While both are inertial sensors, accelerometers respond to changes in speed along a straight line, and gyroscopes sense angular rotation. In modern aircraft, both types are mounted along the aircraft's axes, feeding data to the IRS for accurate attitude and movement calculation.