The image data set may be provided to {TAIL ~ a Head Down Display unit}, a Head Up Display unit, or both, {HEAD ~ each visual aid} is presented on the screen of the display unit 
The image data set may be provided to { TAIL ~ a Head Down Display unit } , a Head Up Display unit , or both , { HEAD ~ each visual aid } is presented on the screen of the display unit
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH