The Mitsubishi MU-300 (Japan designator) is known in America as the Mitsubishi DIAMOND 1, although N8LE is registered as an MU-300. The model was first certificated in the US, then certification in Japan by the JCAB followed. AS N8LE is a 1983 model, its its major sub-assemblies manufactured in Japan were sent to San Angelo, TX to be assembled by Mitsubishi Aircraft International (MAI), flight-tested there and marketed by them at the time.
The landing gear Goodyear brakes are hydraulic, but actuated electrically. There is a free-fall landing gear provision for emergency. Without braking action, the aircraft would need a long runway for rollout as the STALLING speed at an all-up weight of 10,300 lbs is high at 77 knots (89 mph) CAS with flaps down. The pilot probably requested the longest runway on the diversion to KRSN. Their sole runway is 5,000 ft. I would venture most modern hydraulic systems aboard aircraft are actuated electrically to pressurize the hydraulics. The days of aircraft hand pump hydraulics and manual valves are long over.