Narrative:

Aircraft was given a thorough preflight after maintenance work (some cylinders changed and oil leaks repaired). Engines started normal and a 10-15 min ground run performed. Everything checked out ok. Takeoff normal and climb out normal until passing through 4500 ft, when I noticed about a 5 pound drop in fuel pressure and dropping slowly. Turned on boost pump and no change and pressure still dropping, so I shut off fuel to engine from tank (firewall shutoff) and feathered engine and returned to airport. On rollout noticed smoke coming from right hand cowling. Ground personnel removed cowling and extinguished fire in rear of engine compartment. This aircraft is an small transport, was on part 135 maintenance up to 2-3 weeks prior when it was purchased by present owner. This was the first flight after being flown from topeka, ks, to mena, ar, with no problems noted except a few small oil leaks and 2 cracked cylinders which were repaired prior to this flight. I feel very strongly that an airworthiness directive be issued to be sure all fluid carrying hoses be changed every 5 yrs regardless of hours on all turbo-charged aircraft. Also, a placard be applied by manifold pressure gauges to note that if an unexplained manifold pressure drop is noted exceeding 3 inch engine be shut down and land as soon as practical (on turbo-charged aircraft). I have had exhaust leaks develop and almost burn a hole in cowling. The 50 hour inspection is ok but there is a lot of old brittle exhaust system flying around. Callback conversation with reporter revealed the following information: reporter states no way to really determine cause of fire but he has a 'gut' feeling about the fluid carrying hoses on older turbo charged aircraft. Believes 5 yr required replacement would help solve/prevent situations like his. He knows of others who were not so lucky as he and never made it to a safe landing. Idea of a placard by mp gauge is another safety factor to consider.

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Original NASA ASRS Text

Title: ACFT ON TEST FLT HAS FUEL PRESSURE DROP. ENG SHUTDOWN. ON LNDG ROLL OUT SMOKE FROM UNDER COWLING.

Narrative: ACFT WAS GIVEN A THOROUGH PREFLT AFTER MAINT WORK (SOME CYLINDERS CHANGED AND OIL LEAKS REPAIRED). ENGS STARTED NORMAL AND A 10-15 MIN GND RUN PERFORMED. EVERYTHING CHKED OUT OK. TKOF NORMAL AND CLB OUT NORMAL UNTIL PASSING THROUGH 4500 FT, WHEN I NOTICED ABOUT A 5 POUND DROP IN FUEL PRESSURE AND DROPPING SLOWLY. TURNED ON BOOST PUMP AND NO CHANGE AND PRESSURE STILL DROPPING, SO I SHUT OFF FUEL TO ENG FROM TANK (FIREWALL SHUTOFF) AND FEATHERED ENG AND RETURNED TO ARPT. ON ROLLOUT NOTICED SMOKE COMING FROM R HAND COWLING. GND PERSONNEL REMOVED COWLING AND EXTINGUISHED FIRE IN REAR OF ENG COMPARTMENT. THIS ACFT IS AN SMT, WAS ON PART 135 MAINT UP TO 2-3 WKS PRIOR WHEN IT WAS PURCHASED BY PRESENT OWNER. THIS WAS THE FIRST FLT AFTER BEING FLOWN FROM TOPEKA, KS, TO MENA, AR, WITH NO PROBLEMS NOTED EXCEPT A FEW SMALL OIL LEAKS AND 2 CRACKED CYLINDERS WHICH WERE REPAIRED PRIOR TO THIS FLT. I FEEL VERY STRONGLY THAT AN AIRWORTHINESS DIRECTIVE BE ISSUED TO BE SURE ALL FLUID CARRYING HOSES BE CHANGED EVERY 5 YRS REGARDLESS OF HRS ON ALL TURBO-CHARGED ACFT. ALSO, A PLACARD BE APPLIED BY MANIFOLD PRESSURE GAUGES TO NOTE THAT IF AN UNEXPLAINED MANIFOLD PRESSURE DROP IS NOTED EXCEEDING 3 INCH ENG BE SHUT DOWN AND LAND AS SOON AS PRACTICAL (ON TURBO-CHARGED ACFT). I HAVE HAD EXHAUST LEAKS DEVELOP AND ALMOST BURN A HOLE IN COWLING. THE 50 HR INSPECTION IS OK BUT THERE IS A LOT OF OLD BRITTLE EXHAUST SYS FLYING AROUND. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES NO WAY TO REALLY DETERMINE CAUSE OF FIRE BUT HE HAS A 'GUT' FEELING ABOUT THE FLUID CARRYING HOSES ON OLDER TURBO CHARGED ACFT. BELIEVES 5 YR REQUIRED REPLACEMENT WOULD HELP SOLVE/PREVENT SITUATIONS LIKE HIS. HE KNOWS OF OTHERS WHO WERE NOT SO LUCKY AS HE AND NEVER MADE IT TO A SAFE LNDG. IDEA OF A PLACARD BY MP GAUGE IS ANOTHER SAFETY FACTOR TO CONSIDER.

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.