Narrative:

The polyfilament kevlar valve line which attaches to the parachute valve separated in several places, or disintegrated, inside the woven outer protective sheath. The outer sheath was not visibly worn to indicate the interior damage. The outer woven sheath was the only part of the line that was structurally sound previous to the line failure. In other words, the sheath broke when the load was applied because the interior kevlar line inside the sheath had disintegrated. The damage was apparently isolated to the length of line that passes through a guide ring assembly. The probable cause for the kevlar disintegration is from being bent at an acute angle when passing over the very hot guide ring. Kevlar has a critical weakness from being kinked, acutely bent, or overheated. The ring the line must pass through is a large metal ring that would accumulate extreme heat from its proximity to the airborne heater, therefore exposing the line to extreme heat as it contacted the surface of the ring. The angle the kevlar line is bent at over the ring and constant abrasion adds to the disintegration process. This damage could have been exacerbated by the recent addition of a new factory design airborne heater which throws off significantly increased radiant heat from the 'looser' flame confign in close proximity to the guide ring and rope which could result in its increased heat accumulation. Possible solutions could be to change the line to something more heat resistant than kevlar, or replace the ring with a halyard or pulley with non- metallic pulley wheel, and possibly place the ring or pulley assembly further away from the flame to prevent heat accumulation. This is the second time this failure has happened to me. I did not report the first failure to the FAA, but I did report it to the manufacturer. Also, as a separate incident, I had 1 other failure with the same valve line assembly when the keeper ring failed and fell out allowing a pin to fall out of the pulley assembly and the entire assembly came apart leaving the valve inoperable resulting in no control of landing or stopping. I have personal knowledge of other occurrences of both types of failures in this aircraft. The importance of this being corrected is that without an operable valve/line, the aircraft cannot make a controled landing or stop when in contact with the ground. The aircraft is totally out of control. Callback conversation with reporter revealed the following information: the reporter is one of the prime 'ride' operators in the valley. This is the second kevlar vent line that has failed on him. The first one was in a 20 KT wind situation. The reporter handed the first broken line to the president of the manufacturing company. The reporter and the manufacturer agreed that the kevlar had been cut inside the sheath. The second failure, the subject of this report, was a heat failure. The manufacturer has been trying to 'stonewall' the situation, pretend that it didn't happen. The reporter has had another operator in southern ca call him to tell of another failure of the vent. Apparently, the subject balloons cannot be retrofitted with stainless steel cables. Early balloons were all manufactured with stainless steel cables that can conduct electricity when the outer sheath is new, clean, and dry. Kevlar is stronger than steel, but must be handled much more carefully than stainless steel. The reporter filed an 'mdr' report with the FAA and is now aware of the FAA aviation safety hotline. There were no injuries or other damage in any of the incidents so far. The reporter states that it takes about a half hour to deflate a balloon without a vent/deflation line in a high wind.

Related reports:

Google
 

Original NASA ASRS Text

Title: A HOT AIR BALLOON 'RIDE' OPERATOR RPTS THAT HIS KEVLAR VENT DEFLATION LINE HAS BROKEN TWICE.

Narrative: THE POLYFILAMENT KEVLAR VALVE LINE WHICH ATTACHES TO THE PARACHUTE VALVE SEPARATED IN SEVERAL PLACES, OR DISINTEGRATED, INSIDE THE WOVEN OUTER PROTECTIVE SHEATH. THE OUTER SHEATH WAS NOT VISIBLY WORN TO INDICATE THE INTERIOR DAMAGE. THE OUTER WOVEN SHEATH WAS THE ONLY PART OF THE LINE THAT WAS STRUCTURALLY SOUND PREVIOUS TO THE LINE FAILURE. IN OTHER WORDS, THE SHEATH BROKE WHEN THE LOAD WAS APPLIED BECAUSE THE INTERIOR KEVLAR LINE INSIDE THE SHEATH HAD DISINTEGRATED. THE DAMAGE WAS APPARENTLY ISOLATED TO THE LENGTH OF LINE THAT PASSES THROUGH A GUIDE RING ASSEMBLY. THE PROBABLE CAUSE FOR THE KEVLAR DISINTEGRATION IS FROM BEING BENT AT AN ACUTE ANGLE WHEN PASSING OVER THE VERY HOT GUIDE RING. KEVLAR HAS A CRITICAL WEAKNESS FROM BEING KINKED, ACUTELY BENT, OR OVERHEATED. THE RING THE LINE MUST PASS THROUGH IS A LARGE METAL RING THAT WOULD ACCUMULATE EXTREME HEAT FROM ITS PROX TO THE AIRBORNE HEATER, THEREFORE EXPOSING THE LINE TO EXTREME HEAT AS IT CONTACTED THE SURFACE OF THE RING. THE ANGLE THE KEVLAR LINE IS BENT AT OVER THE RING AND CONSTANT ABRASION ADDS TO THE DISINTEGRATION PROCESS. THIS DAMAGE COULD HAVE BEEN EXACERBATED BY THE RECENT ADDITION OF A NEW FACTORY DESIGN AIRBORNE HEATER WHICH THROWS OFF SIGNIFICANTLY INCREASED RADIANT HEAT FROM THE 'LOOSER' FLAME CONFIGN IN CLOSE PROX TO THE GUIDE RING AND ROPE WHICH COULD RESULT IN ITS INCREASED HEAT ACCUMULATION. POSSIBLE SOLUTIONS COULD BE TO CHANGE THE LINE TO SOMETHING MORE HEAT RESISTANT THAN KEVLAR, OR REPLACE THE RING WITH A HALYARD OR PULLEY WITH NON- METALLIC PULLEY WHEEL, AND POSSIBLY PLACE THE RING OR PULLEY ASSEMBLY FURTHER AWAY FROM THE FLAME TO PREVENT HEAT ACCUMULATION. THIS IS THE SECOND TIME THIS FAILURE HAS HAPPENED TO ME. I DID NOT RPT THE FIRST FAILURE TO THE FAA, BUT I DID RPT IT TO THE MANUFACTURER. ALSO, AS A SEPARATE INCIDENT, I HAD 1 OTHER FAILURE WITH THE SAME VALVE LINE ASSEMBLY WHEN THE KEEPER RING FAILED AND FELL OUT ALLOWING A PIN TO FALL OUT OF THE PULLEY ASSEMBLY AND THE ENTIRE ASSEMBLY CAME APART LEAVING THE VALVE INOPERABLE RESULTING IN NO CTL OF LNDG OR STOPPING. I HAVE PERSONAL KNOWLEDGE OF OTHER OCCURRENCES OF BOTH TYPES OF FAILURES IN THIS ACFT. THE IMPORTANCE OF THIS BEING CORRECTED IS THAT WITHOUT AN OPERABLE VALVE/LINE, THE ACFT CANNOT MAKE A CTLED LNDG OR STOP WHEN IN CONTACT WITH THE GND. THE ACFT IS TOTALLY OUT OF CTL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR IS ONE OF THE PRIME 'RIDE' OPERATORS IN THE VALLEY. THIS IS THE SECOND KEVLAR VENT LINE THAT HAS FAILED ON HIM. THE FIRST ONE WAS IN A 20 KT WIND SIT. THE RPTR HANDED THE FIRST BROKEN LINE TO THE PRESIDENT OF THE MANUFACTURING COMPANY. THE RPTR AND THE MANUFACTURER AGREED THAT THE KEVLAR HAD BEEN CUT INSIDE THE SHEATH. THE SECOND FAILURE, THE SUBJECT OF THIS RPT, WAS A HEAT FAILURE. THE MANUFACTURER HAS BEEN TRYING TO 'STONEWALL' THE SIT, PRETEND THAT IT DIDN'T HAPPEN. THE RPTR HAS HAD ANOTHER OPERATOR IN SOUTHERN CA CALL HIM TO TELL OF ANOTHER FAILURE OF THE VENT. APPARENTLY, THE SUBJECT BALLOONS CANNOT BE RETROFITTED WITH STAINLESS STEEL CABLES. EARLY BALLOONS WERE ALL MANUFACTURED WITH STAINLESS STEEL CABLES THAT CAN CONDUCT ELECTRICITY WHEN THE OUTER SHEATH IS NEW, CLEAN, AND DRY. KEVLAR IS STRONGER THAN STEEL, BUT MUST BE HANDLED MUCH MORE CAREFULLY THAN STAINLESS STEEL. THE RPTR FILED AN 'MDR' RPT WITH THE FAA AND IS NOW AWARE OF THE FAA AVIATION SAFETY HOTLINE. THERE WERE NO INJURIES OR OTHER DAMAGE IN ANY OF THE INCIDENTS SO FAR. THE RPTR STATES THAT IT TAKES ABOUT A HALF HR TO DEFLATE A BALLOON WITHOUT A VENT/DEFLATION LINE IN A HIGH WIND.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.