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