Recently, an Immigration and Customs Enforcement drone was on survelience along the southern border of Arizona, and was being 'controlled' from a station in Sierra Vista, when the operators computer screen 'froze'.
The back up plan was to immediately transfer to another computer terminal to regain control.
A checklist was in place to "assure" that the transfer was done in an orderly manner.
However, on this one occasion, the checklist was not followed, and when control was transferred, it was found that the HP fuel valve to the engine was selected to the closed position.
The resulting landing (otherwise known as a crash) was certainly nothing to write home about.
