AX7 BALLOON INSTRUCTOR WITH STUDENT PLT ENCOUNTERS WINDSHEAR ON APCH TO LAND AS DROP LINE RELEASES UNEXPECTEDLY AND PLT ABORTS LNDG ONLY TO ENCOUNTER TREES EXITING THE AREA. THIS ACTIVATES BURNER BLAST VALVE AND DEFLATION VENT LINE BECOMES CAUGHT IN TREE LIMB. BALLOON DEFLATES.

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I WAS CONCLUDING AN HR OF FLT INSTRUCTION IN AN AX7 HOT AIR BALLOON. WE WERE MAKING AN APCH TO LAND IN A FIELD WITH GND CREW STANDING BY ON THE GND. I DROPPED A DROP LINE TO THE CREW TO ASSIST WITH LNDG BECAUSE THERE WAS A WINDSHEAR ABOVE THE SURFACE WINDS. (SURFACE 5 KTS; 100 DEG WINDS; 8-10 KTS.) THE DROPLINE WAS ATTACHED TO THE BALLOON WITH A MARINE TYPE (HVY DUTY) QUICK RELEASE. AS THE CREW GRABBED THE DROPLINE AND THE FORWARD MOTION BEGAN TO STOP; THE QUICK RELEASE SUDDENLY RELEASED. THE STUDENT IMMEDIATELY ADDED HEAT TO THE BALLOON AND I TOOK OVER AND BEGAN TO ABORT THE LNDG DUE TO A 50 FT IN DIAMETER TREE LINE DOWNWIND. IT WAS SAFER TO CONTINUE CLBING OVER THE TREE LINE THAN TO TRY TO LAND THE BALLOON AND DEFLATE BEFORE REACHING THE TREES. THE BALLOON CLBED CLR OF THE LEADING EDGE OF THE TREES BUT AS THE TOP OF BALLOON (WHICH HAD BEEN FLYING WITH AERODYNAMIC LIFT FROM THE FASTER WINDS ALOFT) PICKED UP SPD THE BALLOON DSNDED INTO THE TOP OF THE TREES AND BRANCHES WHICH ACTIVATED THE BURNER BLAST VALVE; BURNING SEVERAL PANELS. (MINOR DAMAGE; NO STRUCTURAL DAMAGE.) AS THE BASKET WAS FREED FROM THE TREE LIMBS THE BALLOON BEGAN TO MOVE DOWNWIND; HOWEVER; THE RED LINE (DEFLATION AND VENT LINE) HUNG IN A TREE LIMB AND DEFLATED THE BALLOON. THE BASKET SETTLED THROUGH THE TREES TO THE GND AND THE ENVELOPE HAD TO BE REMOVED WITH A BUCKET TRUCK. NO INJURIES OR OTHER PROPERTY DAMAGE. THE INCIDENT WAS SET IN MOTION BY A FAULTY QUICK RELEASE WHICH APPARENTLY HAD DIRT OR SOMETHING IN THE MECHANISM WHICH CAUSED IT TO NOT FULLY LOCK. FAILURE TO RECOGNIZE THE EFFECTS OF THE AERODYNAMIC LIFT LED TO THE DROPPING INTO THE TREES. THE BURNER ACTIVATION WAS A FREAK OCCURRENCE (BY TREE LIMBS). FAILURE TO PROTECT THE RED LINE FROM THE TREE LIMBS LED TO THE UNINTENTIONAL DEFLATION.