Routine water washing of the gas turbine engine compressor shown in the illustration, is usually performed while operating under which of the following conditions? Illustration GT-0017

Correct Answer: Option D — With the starter motor drive.

Compressor water washing is performed during the cranking cycle using the starter motor. This ensures that the cleaning solution effectively reaches all blade stages without the risk of thermal shock or combustion instability. Operating the engine under power during washing would cause immediate evaporation and potential damage to components.