A320 THS Electrical Load Sensing Device (ELSD)

The A320 family THSA has a fail-safe design: each attachment, upper and lower, has two load paths, a normally loaded Primary Load Path and a Secondary Load Path, which is only engaged in case of Primary Load Path rupture.

The Electrical Load Sensing Device (ELSD) has been introduced on the THSA in order to detect an engagement of the Secondary Load Path (SLP)

When the ELSD detects a loading of the Secondary Load Path through its load-sensing bolts, the RVDT MON signal is short-circuited.
The RVDT MON signal short-circuit is then detected by the ELAC 2 and trigger NO-GO ECAM Warning “ELAC 2 PITCH FAULT” associated with Fault Message “ELAC2 – MON OR INPUT OF THS ACTR XDCR 1 9CE”.

Author – Zinhom Mohmoud – Aviation Training Consultant