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