Narrative:

On aug/xa/97 I landed at a local airport and requested that a full load of fuel be placed in my aircraft at XA00 the next morning. Normally, I observe the fueling, but wanted the denser, cooler morning fuel and was concerned regarding fuel expansion and venting if I had fueled that afternoon. (A maximum range flight was planned for aug/xb/97.) I had had previous favorable experience with this FBO and felt they could be trusted to fuel the aircraft properly. As a reminder to the lineman who was to fuel it the next morning, I emphasized the need for prist as he was driving me and a passenger to another local airport, where my car was located. I explained the need for the prist to the interested passenger in the presence of the lineman. Before departure aug/xb/97, I confirmed that prist had been added. About 1 hour 45 mins into the flight, I observed a l-hand fuel filter bypass light, followed by a r-hand light 30 seconds later. As this light indicates fuel contamination or icing and possibly impending flameouts, I made an emergency descent and landing at taos. When I declared my need to land at taos, ZDV immediately told me to contact ZAB and I was unable to reach ZAB immediately, which slightly delayed my descent and could have caused a conflict with oncoming traffic. I did use the word 'emergency' once contact was established and the landing was uneventful. I drained fuel samples, which I still have in safekeeping, should testing be indicated. I took on additional fuel (containing prist) and added 2 cans of prist to the existing fuel. The lights extinguished on the ground and the flight was continued uneventfully. I reported the incident to the FBO that sold me the fuel. When I returned, they reported that there may be a problem with the prist injector. The oil company itself checked the truck this week and at present the prist is being properly added to the fuel. At this point, it is not plain to me whether the problem was a mechanical one with the prist injector, or forgetfulness on the part of the lineman. Recommendations: 1) pre-mix the anti-icing additive in the fuel (as one supplier apparently does). It's a good algaecide for the aircraft that don't need anti-icing, and it's not that expensive. 2) develop an easy-to-use cheap test kit, perhaps a dipstick so that the presence of prist can be verified on preflight by the crew. 3) promote awareness on the part of line personnel of the absolute need for this additive on certain aircraft. 4) have FBO's frequently test their fuel. If it had been a flight of lesser duration, or at a lower altitude in warmer air, I would never have known of the discrepancy. Callback conversation with reporter revealed the following information: reporter said he feels that this incident discloses a very important area of aviation safety regarding anti-icing additives to jet fuels for all jet aircraft, including his citation V. Some jet fuel manufacturers add anti-icing agents at the refinery and some, like the fuel he used for his flight have the additive prist added from the fuel truck from a separate tank. This system allows a valve to open up as the fuel is pumped and this 'injector' valve adds the required amount of prist to the fuel being pumped. (The percentages have just recently been increased by the aircraft manufacturer.) in this incident the valve for the prist injector was malfunctioning. It was not opening for the low rate of fuel flow from the truck during the reporter's refueling process as his aircraft uses a gravity feed system. A hawker, for example, would have a higher rate of fuel flowing through its single point, high pressure, fueling and therefore might not have a problem with the prist not being added to the fuel in the correct levels. His main concern is that, as a pilot, he has no way of knowing if the prist was added. The truck method of adding prist is usually done by one person. That person may not have a way of monitoring the 'prist flow bowl,' as that is the only evidence of prist flowing out of the prist tank into the fuel being pumped. There are test kits available, but would these work with a sump drain check? Further, his aircraft does not have a placard stating that he needs a fuel anti-icing additive, it just states that it requires 'jet fuel.' he has talked to other pilots and they all seem to have a story to tell about jet fuel anti-icing additives. His second concern is, 'how long do I have after the fuel filter bypass light comes on before the engines actually flame out?' the manufacturer simply states that a flameout is 'impending.' he stated that this is an important thing to know for flight planning purposes and diversion planning.

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Original NASA ASRS Text

Title: GA PLT OF A CITATION V AT FL410 EXPERIENCES A FUEL WARNING LIGHT THAT INDICATED EITHER FUEL CONTAMINATION OR ICING. HE DECLARED AN EMER AND LANDED AT TAOS, NM. RPTR HAD REQUESTED THAT 'PRIST,' A FUEL ADDITIVE, BE PLACED IN HIS FUEL. HE WAS NOT PRESENT DURING THE REFUELING PROC NEAR DALLAS.

Narrative: ON AUG/XA/97 I LANDED AT A LCL ARPT AND REQUESTED THAT A FULL LOAD OF FUEL BE PLACED IN MY ACFT AT XA00 THE NEXT MORNING. NORMALLY, I OBSERVE THE FUELING, BUT WANTED THE DENSER, COOLER MORNING FUEL AND WAS CONCERNED REGARDING FUEL EXPANSION AND VENTING IF I HAD FUELED THAT AFTERNOON. (A MAX RANGE FLT WAS PLANNED FOR AUG/XB/97.) I HAD HAD PREVIOUS FAVORABLE EXPERIENCE WITH THIS FBO AND FELT THEY COULD BE TRUSTED TO FUEL THE ACFT PROPERLY. AS A REMINDER TO THE LINEMAN WHO WAS TO FUEL IT THE NEXT MORNING, I EMPHASIZED THE NEED FOR PRIST AS HE WAS DRIVING ME AND A PAX TO ANOTHER LCL ARPT, WHERE MY CAR WAS LOCATED. I EXPLAINED THE NEED FOR THE PRIST TO THE INTERESTED PAX IN THE PRESENCE OF THE LINEMAN. BEFORE DEP AUG/XB/97, I CONFIRMED THAT PRIST HAD BEEN ADDED. ABOUT 1 HR 45 MINS INTO THE FLT, I OBSERVED A L-HAND FUEL FILTER BYPASS LIGHT, FOLLOWED BY A R-HAND LIGHT 30 SECONDS LATER. AS THIS LIGHT INDICATES FUEL CONTAMINATION OR ICING AND POSSIBLY IMPENDING FLAMEOUTS, I MADE AN EMER DSCNT AND LNDG AT TAOS. WHEN I DECLARED MY NEED TO LAND AT TAOS, ZDV IMMEDIATELY TOLD ME TO CONTACT ZAB AND I WAS UNABLE TO REACH ZAB IMMEDIATELY, WHICH SLIGHTLY DELAYED MY DSCNT AND COULD HAVE CAUSED A CONFLICT WITH ONCOMING TFC. I DID USE THE WORD 'EMER' ONCE CONTACT WAS ESTABLISHED AND THE LNDG WAS UNEVENTFUL. I DRAINED FUEL SAMPLES, WHICH I STILL HAVE IN SAFEKEEPING, SHOULD TESTING BE INDICATED. I TOOK ON ADDITIONAL FUEL (CONTAINING PRIST) AND ADDED 2 CANS OF PRIST TO THE EXISTING FUEL. THE LIGHTS EXTINGUISHED ON THE GND AND THE FLT WAS CONTINUED UNEVENTFULLY. I RPTED THE INCIDENT TO THE FBO THAT SOLD ME THE FUEL. WHEN I RETURNED, THEY RPTED THAT THERE MAY BE A PROB WITH THE PRIST INJECTOR. THE OIL COMPANY ITSELF CHKED THE TRUCK THIS WK AND AT PRESENT THE PRIST IS BEING PROPERLY ADDED TO THE FUEL. AT THIS POINT, IT IS NOT PLAIN TO ME WHETHER THE PROB WAS A MECHANICAL ONE WITH THE PRIST INJECTOR, OR FORGETFULNESS ON THE PART OF THE LINEMAN. RECOMMENDATIONS: 1) PRE-MIX THE ANTI-ICING ADDITIVE IN THE FUEL (AS ONE SUPPLIER APPARENTLY DOES). IT'S A GOOD ALGAECIDE FOR THE ACFT THAT DON'T NEED ANTI-ICING, AND IT'S NOT THAT EXPENSIVE. 2) DEVELOP AN EASY-TO-USE CHEAP TEST KIT, PERHAPS A DIPSTICK SO THAT THE PRESENCE OF PRIST CAN BE VERIFIED ON PREFLT BY THE CREW. 3) PROMOTE AWARENESS ON THE PART OF LINE PERSONNEL OF THE ABSOLUTE NEED FOR THIS ADDITIVE ON CERTAIN ACFT. 4) HAVE FBO'S FREQUENTLY TEST THEIR FUEL. IF IT HAD BEEN A FLT OF LESSER DURATION, OR AT A LOWER ALT IN WARMER AIR, I WOULD NEVER HAVE KNOWN OF THE DISCREPANCY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID HE FEELS THAT THIS INCIDENT DISCLOSES A VERY IMPORTANT AREA OF AVIATION SAFETY REGARDING ANTI-ICING ADDITIVES TO JET FUELS FOR ALL JET ACFT, INCLUDING HIS CITATION V. SOME JET FUEL MANUFACTURERS ADD ANTI-ICING AGENTS AT THE REFINERY AND SOME, LIKE THE FUEL HE USED FOR HIS FLT HAVE THE ADDITIVE PRIST ADDED FROM THE FUEL TRUCK FROM A SEPARATE TANK. THIS SYS ALLOWS A VALVE TO OPEN UP AS THE FUEL IS PUMPED AND THIS 'INJECTOR' VALVE ADDS THE REQUIRED AMOUNT OF PRIST TO THE FUEL BEING PUMPED. (THE PERCENTAGES HAVE JUST RECENTLY BEEN INCREASED BY THE ACFT MANUFACTURER.) IN THIS INCIDENT THE VALVE FOR THE PRIST INJECTOR WAS MALFUNCTIONING. IT WAS NOT OPENING FOR THE LOW RATE OF FUEL FLOW FROM THE TRUCK DURING THE RPTR'S REFUELING PROCESS AS HIS ACFT USES A GRAVITY FEED SYS. A HAWKER, FOR EXAMPLE, WOULD HAVE A HIGHER RATE OF FUEL FLOWING THROUGH ITS SINGLE POINT, HIGH PRESSURE, FUELING AND THEREFORE MIGHT NOT HAVE A PROB WITH THE PRIST NOT BEING ADDED TO THE FUEL IN THE CORRECT LEVELS. HIS MAIN CONCERN IS THAT, AS A PLT, HE HAS NO WAY OF KNOWING IF THE PRIST WAS ADDED. THE TRUCK METHOD OF ADDING PRIST IS USUALLY DONE BY ONE PERSON. THAT PERSON MAY NOT HAVE A WAY OF MONITORING THE 'PRIST FLOW BOWL,' AS THAT IS THE ONLY EVIDENCE OF PRIST FLOWING OUT OF THE PRIST TANK INTO THE FUEL BEING PUMPED. THERE ARE TEST KITS AVAILABLE, BUT WOULD THESE WORK WITH A SUMP DRAIN CHECK? FURTHER, HIS ACFT DOES NOT HAVE A PLACARD STATING THAT HE NEEDS A FUEL ANTI-ICING ADDITIVE, IT JUST STATES THAT IT REQUIRES 'JET FUEL.' HE HAS TALKED TO OTHER PLTS AND THEY ALL SEEM TO HAVE A STORY TO TELL ABOUT JET FUEL ANTI-ICING ADDITIVES. HIS SECOND CONCERN IS, 'HOW LONG DO I HAVE AFTER THE FUEL FILTER BYPASS LIGHT COMES ON BEFORE THE ENGS ACTUALLY FLAME OUT?' THE MANUFACTURER SIMPLY STATES THAT A FLAMEOUT IS 'IMPENDING.' HE STATED THAT THIS IS AN IMPORTANT THING TO KNOW FOR FLT PLANNING PURPOSES AND DIVERSION PLANNING.

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.