The deposition characteristics of ingested volcanic ash were studied using a small aeroengine. Deposition was assessed using a borescope. Deposition mainly occurred on the nozzle guide vane (see Figure). A numerical model has been used to predict particle acceleration and heating. It is observed that larger particles are more likely to adhere. Larger particles are predicted to be sufficiently hot and are more likely to hit surfaces. Estimated values of Stokes numbers are consistent with the observations.