In another embodiment, {TAIL ~ reference data} could be provided by {HEAD ~ the flight navigation database} 144 
In another embodiment , { TAIL ~ reference data } could be provided by { HEAD ~ the flight navigation database } 144
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH