Friction is generated during {TAIL ~ operation} of the engine between {HEAD ~ the outer surface} of the friction damper and the undersides of two adjacent shrouds 
Friction is generated during { TAIL ~ operation } of the engine between { HEAD ~ the outer surface } of the friction damper and the undersides of two adjacent shrouds
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH