21.   If so, further tests must be done to see if the whole rudder power control unit must be replaced.

22.   If the power control unit jammed, the rudder could stop in mid-movement and come back the other way, causing the plane to roll.

23.   In addition to a redesigned power control unit, Boeing plans to offer new systems to better stabilize the plane in flight and offer improved flight training procedures.

24.   Investigators, however, suspect that wear and tear on the rudder standby power control units on both aircraft could have contributed to the sudden rolls.

25.   It affects the power supply units of some external Jaz disk drives, not the drives themselves.

26.   It has already announced plans to spin off the power unit, YTL Power Services Sdn. Bhd., probably within a year.

27.   It has proposed selling its ground proximity warning systems business, its auxiliary power systems unit and its satellite collision-avoidance systems, the executives said.

28.   Last August, Ericsson opened a joint venture plant in Beijing to produce mobile telephones, base stations for mobile phone systems and power units to run the system.

29.   Later jobs will include adding a main camera and replacing a navigation device and a power distribution unit.