Some of the air leaks radially outwards, to seal the gas annulus against hot gas leaks onto {HEAD ~ the face} of {TAIL ~ the turbine disc} 
of
Some of the air leaks radially outwards , to seal the gas annulus against hot gas leaks onto { HEAD ~ the face } of { TAIL ~ the turbine disc }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL