Flaps and Slats (Contd.)
In addition, to prevent uncommanded motion from occurring on the LE devices
during cruise, the FSEU maintains pressure on the retract lines and depressurizes
the extend and full extend lines.
Trailing Edge Uncommanded Motion
Uncommanded motion is detected when no FLAP lever or flap load relief
command is present and the TE flaps:
- Move away from the commanded position.
- Continue to move after reaching a commanded position, or
- move in a direction opposite to that commanded.
The FSEU shuts down the TE drive unit by closing the TE flap bypass valve. The
TE flap shutdown cannot be reset by the flight crew and they must use the alternate flap
system to control TE flaps. The shutdown is indicated by the flap position indicator
disagreeing with the FLAP lever position. There is no flap needle split.
