The Homeland Security Department is back to flying drones along the country’s borders more than a week after one crashed into the Pacific Ocean.

Customs and Border Protection spokesman Michael Friel said an initial investigation concluded that the drone crashed due to a generator failure. The department is making mechanical upgrades to the remaining drones in the fleet to safeguard against future malfunctions.

The $12 million surveillance drone was flying a border security mission along the southern border when the generator failed and the Texas-based crew decided to down it in the ocean about 20 miles southwest of San Diego.

The crashed aircraft was one of 10 drones used by the government to patrol the borders from the air.