Narrative:

Mechanical failure resulting in inaccessible fuel and subsequent uncontrolled landing. FAA and NTSB has designated this an incident. Aircraft operation was normal and standard with no anomalies. I had ascended and was cruising at approximately 1400 ft MSL. In standard operation procedure, I attempted to switch from tank #1 to tank #3. The valve would not accept the hose fitting. I made multiple attempts without success. To test the hose fitting, I successfully reattached the fuel hose to tank #1. I again attempted to attach the hose to tank #3. I lubricated both the hose and the valve fitting with silicone lubricant, and made several more attempts to connect the hose to tank #3 valve, without success. I proceeded to relieve the internal valve pressure and concluded I had done so successfully, or that there was no internal pressure to be released, but the fitting would not connect. During this proceeding, I successfully reconnected the hose to tank #1 on more than one occasion as a test. I reconnected tank #1 which had approximately 25 percent fuel remaining, kept the valve off and let it situation idle and rest. During this period of time, I continued flying the balloon in a normal manner off tank #2. I continued to fly off tank #2 for some time to assess and rethink the situation, attend to navigation and passenger, and give the tank, the attempt, and myself time to regroup, without a doubt my next attempt would be successful. I was also confident I had fuel in tanks #2 and #4 remaining. Again, I attempted to switch from tank #1 to tank #3, repeating all of the above steps, thoroughly and methodically, without success. Astonished at the failure to connect, I turned my attention to navigation and assessed the situation. I turned my attention to switching over tank #2 to tank #4. I attempted to connect the hose to tank #4 without success. I returned to tank #1 to make another attempt to switch to tank #3, repeating all the steps I had tried previously, without success. I reconnected tank #1 to continue flying with purpose of getting on the ground as soon as possible while attempting to connect tank #4 again, without success. As I descended from approximately 1400 ft MSL to approximately 400 ft AGL I exhausted tank #1 fuel. I continued to negotiate a landing on tank #2 until all fuel was exhausted. The pilot lights extinguished on both burners and would not relight after multiple attempts. All fuel in tanks #1 and #2 was exhausted. The aircraft descended from about 300-400 ft AGL impacting power lines, one which broke when stretched, which did not result in any electrical event. The aircraft landed hard upon a rural driveway. Just previous to contacting the power lines, I shut off the pilot light valves. Just previous to contact with the ground, I opened the deflation valve fully. The aircraft recoiled and the gondola came to rest about 15 ft from the road in a vineyard, between two rows of grapevines. It is my opinion that the valve has a design feature that could probably contribute to this failure for a successful hose connection. The fuel shutoff valve on the fuel tank has a fuel flow check valve downstream from the shutoff valve which will preclude free fuel flow of fuel from the tank if the valve is opened and the fuel is released unrestricted into the open atmosphere. There is a chamber that is formed internally in the valve between the shutoff valve and the fuel flow check valve. There are circumstances that can allow this chamber to fill with fuel which in turn builds high internal pressure within that chamber. This internal pressure can create pressure against the check valve, locking it in the closed position, which can make it difficult for the fuel flow check valve to operate freely. When the fuel flow check valve is in the closed position, it is not possible for the fuel hose fitting to be successfully connected to the fuel tank valve. Opportunities for this valve to build pressure in the internal chamber and locking the fuel flow check valve in place are: a) a leaking fuel shutoff valve which fuel may bypass, B) residual fuel in the chamber from refueling, C) fuelentering cold and remaining to expand as it warmed, increasing pressure exponentially. A very high internal chamber pressure would make it difficult, or in this case, impossible, to connect the hose fitting. I believe this situation occurred because pressure was so high that I could not successfully release the internal chamber pressure.

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Original NASA ASRS Text

Title: A CAMERON BALLOON PLT HAS A FORCED HARD LNDG WHEN HE RUNS OUT OF FUEL AFTER FAILING IN ATTEMPTING A SERIES OF FUEL LINE CONNECTS TO THE RESERVE FUEL TANKS NEAR APA, CA.

Narrative: MECHANICAL FAILURE RESULTING IN INACCESSIBLE FUEL AND SUBSEQUENT UNCTLED LNDG. FAA AND NTSB HAS DESIGNATED THIS AN INCIDENT. ACFT OP WAS NORMAL AND STANDARD WITH NO ANOMALIES. I HAD ASCENDED AND WAS CRUISING AT APPROX 1400 FT MSL. IN STANDARD OP PROC, I ATTEMPTED TO SWITCH FROM TANK #1 TO TANK #3. THE VALVE WOULD NOT ACCEPT THE HOSE FITTING. I MADE MULTIPLE ATTEMPTS WITHOUT SUCCESS. TO TEST THE HOSE FITTING, I SUCCESSFULLY REATTACHED THE FUEL HOSE TO TANK #1. I AGAIN ATTEMPTED TO ATTACH THE HOSE TO TANK #3. I LUBRICATED BOTH THE HOSE AND THE VALVE FITTING WITH SILICONE LUBRICANT, AND MADE SEVERAL MORE ATTEMPTS TO CONNECT THE HOSE TO TANK #3 VALVE, WITHOUT SUCCESS. I PROCEEDED TO RELIEVE THE INTERNAL VALVE PRESSURE AND CONCLUDED I HAD DONE SO SUCCESSFULLY, OR THAT THERE WAS NO INTERNAL PRESSURE TO BE RELEASED, BUT THE FITTING WOULD NOT CONNECT. DURING THIS PROCEEDING, I SUCCESSFULLY RECONNECTED THE HOSE TO TANK #1 ON MORE THAN ONE OCCASION AS A TEST. I RECONNECTED TANK #1 WHICH HAD APPROX 25 PERCENT FUEL REMAINING, KEPT THE VALVE OFF AND LET IT SIT IDLE AND REST. DURING THIS PERIOD OF TIME, I CONTINUED FLYING THE BALLOON IN A NORMAL MANNER OFF TANK #2. I CONTINUED TO FLY OFF TANK #2 FOR SOME TIME TO ASSESS AND RETHINK THE SIT, ATTEND TO NAV AND PAX, AND GIVE THE TANK, THE ATTEMPT, AND MYSELF TIME TO REGROUP, WITHOUT A DOUBT MY NEXT ATTEMPT WOULD BE SUCCESSFUL. I WAS ALSO CONFIDENT I HAD FUEL IN TANKS #2 AND #4 REMAINING. AGAIN, I ATTEMPTED TO SWITCH FROM TANK #1 TO TANK #3, REPEATING ALL OF THE ABOVE STEPS, THOROUGHLY AND METHODICALLY, WITHOUT SUCCESS. ASTONISHED AT THE FAILURE TO CONNECT, I TURNED MY ATTENTION TO NAV AND ASSESSED THE SIT. I TURNED MY ATTENTION TO SWITCHING OVER TANK #2 TO TANK #4. I ATTEMPTED TO CONNECT THE HOSE TO TANK #4 WITHOUT SUCCESS. I RETURNED TO TANK #1 TO MAKE ANOTHER ATTEMPT TO SWITCH TO TANK #3, REPEATING ALL THE STEPS I HAD TRIED PREVIOUSLY, WITHOUT SUCCESS. I RECONNECTED TANK #1 TO CONTINUE FLYING WITH PURPOSE OF GETTING ON THE GND ASAP WHILE ATTEMPTING TO CONNECT TANK #4 AGAIN, WITHOUT SUCCESS. AS I DESCENDED FROM APPROX 1400 FT MSL TO APPROX 400 FT AGL I EXHAUSTED TANK #1 FUEL. I CONTINUED TO NEGOTIATE A LNDG ON TANK #2 UNTIL ALL FUEL WAS EXHAUSTED. THE PLT LIGHTS EXTINGUISHED ON BOTH BURNERS AND WOULD NOT RELIGHT AFTER MULTIPLE ATTEMPTS. ALL FUEL IN TANKS #1 AND #2 WAS EXHAUSTED. THE ACFT DESCENDED FROM ABOUT 300-400 FT AGL IMPACTING PWR LINES, ONE WHICH BROKE WHEN STRETCHED, WHICH DID NOT RESULT IN ANY ELECTRICAL EVENT. THE ACFT LANDED HARD UPON A RURAL DRIVEWAY. JUST PREVIOUS TO CONTACTING THE PWR LINES, I SHUT OFF THE PLT LIGHT VALVES. JUST PREVIOUS TO CONTACT WITH THE GND, I OPENED THE DEFLATION VALVE FULLY. THE ACFT RECOILED AND THE GONDOLA CAME TO REST ABOUT 15 FT FROM THE ROAD IN A VINEYARD, BETWEEN TWO ROWS OF GRAPEVINES. IT IS MY OPINION THAT THE VALVE HAS A DESIGN FEATURE THAT COULD PROBABLY CONTRIBUTE TO THIS FAILURE FOR A SUCCESSFUL HOSE CONNECTION. THE FUEL SHUTOFF VALVE ON THE FUEL TANK HAS A FUEL FLOW CHK VALVE DOWNSTREAM FROM THE SHUTOFF VALVE WHICH WILL PRECLUDE FREE FUEL FLOW OF FUEL FROM THE TANK IF THE VALVE IS OPENED AND THE FUEL IS RELEASED UNRESTRICTED INTO THE OPEN ATMOSPHERE. THERE IS A CHAMBER THAT IS FORMED INTERNALLY IN THE VALVE BETWEEN THE SHUTOFF VALVE AND THE FUEL FLOW CHK VALVE. THERE ARE CIRCUMSTANCES THAT CAN ALLOW THIS CHAMBER TO FILL WITH FUEL WHICH IN TURN BUILDS HIGH INTERNAL PRESSURE WITHIN THAT CHAMBER. THIS INTERNAL PRESSURE CAN CREATE PRESSURE AGAINST THE CHK VALVE, LOCKING IT IN THE CLOSED POSITION, WHICH CAN MAKE IT DIFFICULT FOR THE FUEL FLOW CHK VALVE TO OPERATE FREELY. WHEN THE FUEL FLOW CHK VALVE IS IN THE CLOSED POSITION, IT IS NOT POSSIBLE FOR THE FUEL HOSE FITTING TO BE SUCCESSFULLY CONNECTED TO THE FUEL TANK VALVE. OPPORTUNITIES FOR THIS VALVE TO BUILD PRESSURE IN THE INTERNAL CHAMBER AND LOCKING THE FUEL FLOW CHK VALVE IN PLACE ARE: A) A LEAKING FUEL SHUTOFF VALVE WHICH FUEL MAY BYPASS, B) RESIDUAL FUEL IN THE CHAMBER FROM REFUELING, C) FUELENTERING COLD AND REMAINING TO EXPAND AS IT WARMED, INCREASING PRESSURE EXPONENTIALLY. A VERY HIGH INTERNAL CHAMBER PRESSURE WOULD MAKE IT DIFFICULT, OR IN THIS CASE, IMPOSSIBLE, TO CONNECT THE HOSE FITTING. I BELIEVE THIS SIT OCCURRED BECAUSE PRESSURE WAS SO HIGH THAT I COULD NOT SUCCESSFULLY RELEASE THE INTERNAL CHAMBER PRESSURE.

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.