{HEAD ~ The method} also includes the step of sensing a parameter representative of {TAIL ~ air flow} through the hole 
{ HEAD ~ The method } also includes the step of sensing a parameter representative of { TAIL ~ air flow } through the hole
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH