21.   Jets have hydraulic systems, which work like power steering on a car and can exert hundreds of pounds of force.

22.   Many also have hydraulic systems that allow the car to rear up or bounce.

23.   Materials are also better, Pecho said, with aluminum and magnesium mechanisms and smaller, more powerful motors and hydraulic systems.

24.   Mission managers have tightened restrictions on allowable wind speeds because of problems with a hydraulic system that steers and brakes the shuttle during landing.

25.   Most of the work is in reassembly, cleaning, inspections and repairing leaky hydraulic systems.

26.   NASA mission managers decided there was no reason to curtail the flight that will retrieve Lucid from Mir because of the failure of a redundant shuttle hydraulic system.

27.   On Thursday morning, Rodney Slater, the secretary of transportation, announced a plan to evaluate nonstructural systems, including wiring and hydraulic systems.

28.   One crashed after it rolled to one side because of a hydraulic system malfunction undetected by maintenance workers.

29.   Only one of the three identical hydraulic systems, which are used to control wing flaps, the rudder and landing gear, is malfunctioning.

30.   Rober is one of the few people left who actually understand the hydraulic system, and he must make all repairs himself.