When {TAIL ~ the timer} has expired at step 325, a second recovery function is selected at {HEAD ~ step} 330 that will be performed if a fault occurs 
When { TAIL ~ the timer } has expired at step 325 , a second recovery function is selected at { HEAD ~ step } 330 that will be performed if a fault occurs
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH