Accelerometers are generally used on gas turbine engines to sense which of the following?

Correct Answer: Option D — High frequency vibration.

Accelerometers are piezoelectric transducers used to monitor high-frequency vibration in rotating machinery. By measuring the acceleration of the casing, they provide critical data for detecting bearing wear, blade imbalance, or shaft misalignment. Early detection of these vibrations is essential for preventing catastrophic mechanical failure in high-speed gas turbine assemblies.