A weakened zone of said tube section is automatically broken during lift off by {TAIL ~ a mechanism} applying a tensile stress to {HEAD ~ the section} 
A weakened zone of said tube section is automatically broken during lift off by { TAIL ~ a mechanism } applying a tensile stress to { HEAD ~ the section }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD