Gas turbine engine failure detection

A method, comprising:

• establishing a rotational speed of a gas turbine engine compressor fan;
• establishing a rotational acceleration of a compressor;
• determining a fault signal based upon a reference speed, the rotational speed of the gas turbine engine compressor fan, and the rotational acceleration of the compressor;
• and
• setting a fault indication when the fault signal exceeds a threshold.

An apparatus, comprising:

• a gas turbine engine including a compressor rotor;
• a sensor operable to generate a sensed value representative of the speed of the compressor rotor;
• a controller for use with the gas turbine engine having:
• a reference value representative of a monitored condition;
• an error value representative of the difference between the sensed value and the reference value;
• and
• a fault detector responsive to the error value, the fault detector operable to accumulate the error value and set a fault indicator when an accumulation value exceeds a selected threshold.