Originally Posted by
steveggetit
do arriving passengers at T4S and in transit to another T4S flight have to go back to the main T4 building for security ?
There is transit security in T4S. Your actual transit route within T4S will depend on whether you are entering/leaving Schengen on either flight which would also require you to pass through passport control.
This page explains the various
Iberia - Connections at Madrid Airport