11. The power control unit on the Southwest jet failed tests before being reinstalled, he said. 12. The changing of the power control unit could be the most nerve-racking task during the repair mission. 13. Later tests revealed that the power control unit in that plane actually functioned backwards in certain circumstances. 14. "Based on tests we've done, the power control unit did what the control system told it to do," 15. _A Southwest 737 was returned to service with a rudder power control unit improperly reassembled in December 1996. 16. On each spacecraft, the power subsystem consists of a battery and the power control unit ( PCU ). 17. The power control unit , located in the tail of the airplane, operates similarly to power steering in a car. 18. The modification will require airlines to remove the airplane's power control unit , replace it with a newly designed model. 19. They discussed " erratic yaw damper behavior " and " rudder deflections " and " power control units ." 20. Unlike most major Hubble components, the power control unit was never designed to be worked on by spacewalking astronauts.
