Executive Air Transport, Inc.

FIRE INDICATION ON LEFT ENGINE DURING LOW LEVEL CRUISE FLIGHT. NO SMOKE OR EVIDENCE OF FIRE OBSERVED BY FLIGHT CREW. FIRE WARNING ON PANEL ONLY. ENGINE SHUT DOWN AND SECURED BY FLIGHT CREW AS A PRECAUTION. LANDING UNEVENTFULL. UPON LANDING NO EVIDENCE OF FIRE WAS FOUND EITHER INSIDE ENGINE COMPARTMENT OR ON AIRFRAME/ENGINE NACELLE IN GENERAL. SUSPECT FIRE WARNING/DETECTION SYSTEM HAS INTERMITTENT FAILURE. CURRENTLY TESTING SYSTEM.

EN ROUTE, PART 91 FLIGHT. LT ENGINE FIRE INDICATION, LIGHTS AND WARNINGS. NO REAL SMOKE OR FLAMES NOTED, BUT SOME SMALL AMOUNT OF WHITE SMOKE OBSERVED FROM LT NACELLE. FLIGHT CREW SHUTDOWN LT ENGINE AND PERFORMED CHECK LIST, REQUIRING FIRE BOTTLE ACTIVATION. WITH ENGINE SECURED (NO FUEL TO ENGINE AND PROP FEATHERED) AND FIRE BOTTLE ACTIVATION, FIRE WARNING EXTINGUISHED. AIRCRAFT WAS FLOW TO BASE AND LANDED SAFELY. POST LANDING INSPECTION YIELDED NO OBSERVED OVER TEMP, OR FIRE EVIDENCE. SUSPECT FALSE INDICATION, BUT INVESTIGATION IS ON-GOING.

CRACKS IN THE ENGINE CYLINDERS. EXPERIENCED ALMOST 80 PERCENT FAILURE IN TITAN NICKLE CYLINDERS IN THIS ACFT AND 50 PERCENT FAILURE ON 1 OTHER ACFT WE OPERATE. THE CRACKS ARE IN BETWEEN COOLING FINS ABOUT 1" TO THE BACK AND TO THE RT OF THE FUEL INJECTOR BOSS. (LOOK IN THE DIRECTION OF THE CYLINDER BASE FLANGE) FUEL STAINS APPEAR IN ABOUT THE 17TH COOLING FIN AREA, RIGHT ABOVE THE INTAKE VALVE PORT, LOOK FOR THE BLUE STAIN DOWN BETWEEN THE COOLING FINES. THESE ARE "J" CASTING CYLINDERS. ALL ENGINES ARE ABOUT 3 YEARS OLD, OPERATED NORMALLY AND ACFT FLOWN REGULARLY. THE CRACKS APPEAR ABOUT 2 YEARS FROM MFG AND LESS THAN 700 HOURS, SOMETIMES AS FEW AS 400 HOURS. OUT OF 2 ACFT WITH 24 CYLINDERS BETWEEN THEM WE HAVE EXPERIENCED 6 CRACKED CYLINDERS, ON 1 ACFT AND 9 ON THE OTHER ACFT. I BELIEVE THIS IS A CASTING FLAW AND THAT BEFORE TBO PROBABLY ALL CYLINDERS WILL CRACK.