Thus, {TAIL ~ the second engine} is centrally disposed upon {HEAD ~ the gear box} and is surrounded by the accessories and starter motor  
Thus , { TAIL ~ the second engine } is centrally disposed upon { HEAD ~ the gear box } and is surrounded by the accessories and starter motor
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH