Upon return from routine flight; the owner of a piper aerostar 601B notifies mechanic with inspectio...

Narrative:

Upon return from routine flight; the owner notified me that he had noticed 'red' fuel seeping from improperly seated main tank cap. He stated that he had notified the fuel handler of the situation and reviewed fuel truck fuel certifications and logs. Then he took a fuel sample from each drain port and was satisfied that the fuel was ok. I drained fuel from each port and noticed that it was clear and had an oily feel to the fuel from the auxiliary tank. The aircraft was grounded pending results of the fuel sample. The 1 gal sample was sent to fuel testing lab. The sample confirmed that jet or diesel is present in the fuel. Aircraft grounding continues pending inspections in accordance with lycoming SB398. All applicable parties have been notified as well as the area FAA where the fuel had been purchased. Copies of the sample results were provided to all parties. We were unable to determine the exact ratio of contamination or if all tanks were involved or just the auxiliary tank because the aircraft had been refueled on his second leg with exception to the auxiliary tank. 160+ gals were loaded at this fueling station. Callback conversation with reporter revealed the following information: reporter stated he was originally informed by the test lab there was jet or diesel present in the AVGAS fuel sample he had sent to the test facility. So they drained the entire fuel tank system. This was followed by a compression check of the tio-540-U2 lycoming engine. He also did an extensive colored borescope inspection of the engine cylinders; piston heads for predetonation damage and the valve edges for any signs of metal fatigue; indicated by the valve(south) taking on the shape of a tulip; also known as the 'tulip effect'; that could be caused by fuel contamination with lower octane diesel or jet fuel. No damage was found. Reporter stated further investigation turned to a fuel additive known as 'prist' that also adds a reddish color to the fuel. Reporter stated the test lab later backed off of the position that the test sample was diesel or jet fuel. Currently; they are taking fuel samples every 100 hours and borescoping for valve damage that would be the first indication of an actual low octane or fuel contamination.

Original NASA ASRS Text

Title: UPON RETURN FROM ROUTINE FLIGHT; THE OWNER OF A PIPER AEROSTAR 601B NOTIFIES MECHANIC WITH INSPECTION AUTHORITY (IA); HE HAD NOTICED 'RED' FUEL SEEPING FROM IMPROPERLY SEATED MAIN TANK CAP.

Narrative: UPON RETURN FROM ROUTINE FLT; THE OWNER NOTIFIED ME THAT HE HAD NOTICED 'RED' FUEL SEEPING FROM IMPROPERLY SEATED MAIN TANK CAP. HE STATED THAT HE HAD NOTIFIED THE FUEL HANDLER OF THE SITUATION AND REVIEWED FUEL TRUCK FUEL CERTIFICATIONS AND LOGS. THEN HE TOOK A FUEL SAMPLE FROM EACH DRAIN PORT AND WAS SATISFIED THAT THE FUEL WAS OK. I DRAINED FUEL FROM EACH PORT AND NOTICED THAT IT WAS CLR AND HAD AN OILY FEEL TO THE FUEL FROM THE AUX TANK. THE ACFT WAS GROUNDED PENDING RESULTS OF THE FUEL SAMPLE. THE 1 GAL SAMPLE WAS SENT TO FUEL TESTING LAB. THE SAMPLE CONFIRMED THAT JET OR DIESEL IS PRESENT IN THE FUEL. ACFT GROUNDING CONTINUES PENDING INSPECTIONS IN ACCORDANCE WITH LYCOMING SB398. ALL APPLICABLE PARTIES HAVE BEEN NOTIFIED AS WELL AS THE AREA FAA WHERE THE FUEL HAD BEEN PURCHASED. COPIES OF THE SAMPLE RESULTS WERE PROVIDED TO ALL PARTIES. WE WERE UNABLE TO DETERMINE THE EXACT RATIO OF CONTAMINATION OR IF ALL TANKS WERE INVOLVED OR JUST THE AUX TANK BECAUSE THE ACFT HAD BEEN REFUELED ON HIS SECOND LEG WITH EXCEPTION TO THE AUX TANK. 160+ GALS WERE LOADED AT THIS FUELING STATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HE WAS ORIGINALLY INFORMED BY THE TEST LAB THERE WAS JET OR DIESEL PRESENT IN THE AVGAS FUEL SAMPLE HE HAD SENT TO THE TEST FACILITY. SO THEY DRAINED THE ENTIRE FUEL TANK SYSTEM. THIS WAS FOLLOWED BY A COMPRESSION CHECK OF THE TIO-540-U2 LYCOMING ENGINE. HE ALSO DID AN EXTENSIVE COLORED BORESCOPE INSPECTION OF THE ENGINE CYLINDERS; PISTON HEADS FOR PREDETONATION DAMAGE AND THE VALVE EDGES FOR ANY SIGNS OF METAL FATIGUE; INDICATED BY THE VALVE(S) TAKING ON THE SHAPE OF A TULIP; ALSO KNOWN AS THE 'TULIP EFFECT'; THAT COULD BE CAUSED BY FUEL CONTAMINATION WITH LOWER OCTANE DIESEL OR JET FUEL. NO DAMAGE WAS FOUND. REPORTER STATED FURTHER INVESTIGATION TURNED TO A FUEL ADDITIVE KNOWN AS 'PRIST' THAT ALSO ADDS A REDDISH COLOR TO THE FUEL. REPORTER STATED THE TEST LAB LATER BACKED OFF OF THE POSITION THAT THE TEST SAMPLE WAS DIESEL OR JET FUEL. CURRENTLY; THEY ARE TAKING FUEL SAMPLES EVERY 100 HOURS AND BORESCOPING FOR VALVE DAMAGE THAT WOULD BE THE FIRST INDICATION OF AN ACTUAL LOW OCTANE OR FUEL CONTAMINATION.

Data retrieved from NASA's ASRS site as of May 2009 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.

Attributes
ACN	800606
Time
Date	200808
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Make Model Name	PA-60 601/601P Aerostar
Operating Under FAR Part	Part 135
Flight Phase	ground : maintenance
Person 1
Affiliation	other
Function	maintenance : technician
Qualification	technician : airframe technician : inspection authority technician : powerplant
ASRS Report	800606
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence : published procedure
Independent Detector	other other : 1
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Company Flight Crew Human Performance Aircraft
Primary Problem	Ambiguous

Upon return from routine flight; the owner of a piper aerostar 601B notifies mechanic with inspection authority (ia); he had noticed 'red' fuel seeping from improperly seated main tank cap.