{HEAD ~ The flaps} are biased towards {TAIL ~ the extended position}, and normally retained in the inner position by retaining devices 
are biased towards
{ HEAD ~ The flaps } are biased towards { TAIL ~ the extended position } , and normally retained in the inner position by retaining devices
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH