[willk]

“I don’t understand how the pilot can have control of anything if there’s no engines. No engines means no hydraulics. No hydralics means there’s no controls period.”

There is a little ram jet engine that drops down and will power the hydralics and provide power to the instruments if the engines are not running.

[A.A. Cunningham]

There is a little ram jet engine(sic)

Ram Air Turbine generator.

Hudson A320: Partial engine power aided textbook ditching