MGR OF ACFT FOR BUSINESS AND COMMERCIAL OPS RPTS DAMAGE TO PISTON ENGS FROM FUEL CONTAMINATION TRACED TO A FUELING TRUCK.

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MY COMPANY OPERATES AND MANAGES SEVERAL ACFT FOR BUSINESS AND COMMERCIAL OPS. IN OR ABOUT JUN/04; WE STARTED HAVING PROBS WITH PISTON ACFT WHICH APPEARED TO BE THE RESULT OF LEAN BURNING. WE TOOK VARIOUS ACTIONS INCLUDING SPARK PLUG REPLACEMENT; CARB OVERHAULS AND CYLINDER CHANGES; BUT THE SYMPTOMS CONTINUED. IN FEB/05 WE GNDED OUR FLEET AFTER ONE OF OUR CLIENTS TRACED CONTAMINATION IN HIS FUEL TO A RUSTY FUEL TRUCK BEING OPERATED BY THE FBO. THIS CLIENT HAD BEEN HAVING SIMILAR PROBS FOR SOME TIME. BORESCOPE EXAM REVEALED CYLINDER DAMAGE THROUGHOUT OUR FLEET; AND FURTHER DISASSEMBLY REVEALED VARIOUS DEGREES OF DAMAGE INCLUDING SEVERELY OVERHEATED CONNECTING RODS AND DETONATION DAMAGE. THE FUEL PROVIDER AND PRODUCER WERE INVOLVED. THIS STARTED AN ONGOING EFFORT ON OUR PART TO DISCOVER EXACTLY WHAT HAS OCCURRED. FUEL SAMPLES HAVE BEEN ANALYZED AND FOUND TO BE OUT OF SPEC PER ASTM STANDARDS; PARTICULARLY WITH REGARD TO LEAD PRECIPITATE. OIL ANALYSIS HAS CONSISTENTLY SHOWN HIGH IRON OXIDE LEVELS. SOME ACFT HAVE BEEN RETURNED TO SVC AFTER ENG OR CYLINDER REPLACEMENT. OTHERS ARE STILL OTS. MY CONCERN HAS TO DO WITH POTENTIALLY EXPOSED ACFT BEING OPERATED WITHOUT THE OPERATOR'S KNOWLEDGE OF THESE EVENTS. THE FAA/FSDO WAS INVOLVED IN THIS INVESTIGATION; BUT TO MY KNOWLEDGE NO SIGNIFICANT EFFORT HAS BEEN MADE TO NOTIFY OWNERS OF EXPOSED ACFT. IT IS MY FEELING THAT 2 PROBS EXIST: THE RUST WHICH CAUSED BLOCKING OF FUEL SYS COMPONENTS; AND THE FUEL QUALITY WITH UNDETERMINED EFFECTS. I CONTINUE TO HEAR OF AREA ACFT OWNERS WHO HAVE HAD RECENT MAINT DUE TO UNEXPLAINED LOSS OF CYLINDER COMPRESSION. I FEEL THAT WE NEED SOME ASSISTANCE IN DETERMINING THE TRUE EXTENT OF THE PROB AND NOTIFYING OWNERS OF POTENTIALLY AFFECTED ACFT THAT DETAILED INSPECTIONS ARE WARRANTED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE DAMAGE INCURRED TO THE ENGS WAS MAINLY TRACED TO A HIGHER LEAD PRECIPITATE IN THE FUEL BLEND. RPTR NOTED THE ENG DAMAGE RUNS FROM BLOCKED FUEL INJECTORS; BURNED VALVES; CONNECTING RODS OVERHEATED AND PURPLE IN COLOR; COOLING FINS WITH DIRECT EVIDENCE OF OVERHEATING AND LEAN BURN. THE RPTR STATED THE FUEL SAMPLES WERE SENT TO 2 SEPARATE LABORATORIES FOR ANALYSIS AND BOTH INDICATED HIGHER LEAD PRECIPITATE; WHICH WHEN USED IN A SUPERCHARGED ENG; WILL ACTUALLY LOWER THE ANTI-KNOCK OCTANE RATING. THE RPTR INDICATED A NUMBER OF ACFT OWNERS WITH DAMAGED ENGS HAVE SETTLED WITH INSURANCE CARRIERS. THE RPTR INDICATED THIS PROB IS A REGIONAL ONE AS AIRPLANES FROM ALL OVER THE AREA HAVE FUELED AT THIS ARPT AND MAY NOT HAVE KNOWN OF THE FUEL CONTAMINATION.