It is known to provide in non-rigid airships such as gas balloons (helium, coal gas or hydrogen) a so-called "rip" panel which, when opened by pulling on a rip cord, permits rapid deflation of the balloon.  Typically such rip panels are positioned in one of the gores of the envelope near a top thereof such that the lifting gas in the envelope can rapidly escape for deflation at landing. 
It has been known to provide a rip panel as a pie-shaped pull-out section which is glued in place with a narrow strip of rubber cement around the periphery.  After flight termination, the adhesive is reapplied to the pie-shaped rip panel and it is positioned in its proper place on the envelope to allow the adhesive to dry. 
It is also known to provide a rip panel system wherein small grommets with apertures therein such as those employed in shoes for lacing are provided around a periphery of the rip panel and corresponding aperture.  A small cotton break cord is laced through these holes and tied at each matching pair of grommets, so as to hold the rip panel in place.  The lacing and the gap is then covered with an adhesive pressure sensitive tape which is thereafter hand rolled to apply pressure to assure a gas tight bond.  Several hours are required for one to lace and seal such a closure to make the balloon ready for flight.  Also, extremely cold temperatures can cause the adhesive tape to lose its holding capability and hot temperatures tend to wrinkle the tape and allow horizontal tunnels to form gas leakage passages.