An extraction unit was damaged in a fire at BAE’s Samlesbury base.
Firefighters were called to land off Myerscough Smithy Road at 2pm on Tuesday.
Preston watch manager Caroline Sturgess said the fire was out on their arrival.
She said: “The staff at BAE were fantastic.
They have got their own firefighting teams, so they gathered some information for us and isolated the machinery and it had gone out on its own, because they had done everything right.”
The fire caused severe damage to a timing belt on an air extraction unit and slight damage by smoke to the remainder of the unit.