Flaps and Slats (Contd.)
Asymmetry and Skew Detection, Protection and Indication
The FSEU monitors the TE flaps for asymmetry and skew conditions. It also monitors the LE
devices for improper position and skew conditions on slats 2 through 7. If a flap on one
wing does not align with the symmetrical flap on the other wing, there is a flap asymmetry
condition. A skew condition occurs when a TE flap or LE slat panel does not operate at the
same rate causing the panel to twist during extension or retraction.
When the FSEU detects a trailing edge asymmetry or skew condition the FSEU:
Uncommanded Motion Detection, Protection and Indication
The FSEU provides protection from uncommanded motion by the LE devices or TE flaps.
Leading Edge Uncommanded Motion
Uncommanded motion is detected when no TE flap position or autoslat command
is present and:
- Two LE flaps move on one wing, or
- two or more slats move on one wing.
The FSEU shuts down the LE control and illuminates the amber LE FLAPS
TRANSIT light.
- Closes the TE flap bypass valve.
- Displays a needle split on the flap position indicator.
