Narrative:

After completing an extensive annual inspection; dated jan/sun/05; of a C337G; the subject aircraft was returned to service. After several local flts; one of which was several hours long; the aircraft was deemed ready to return to its base in canada. Upon arrival at its final destination; the pilot reported back to us that he had an engine failure in-flight and the landing gear motor circuit breaker opened 3 times in-flight. Upon inspection by a local mechanic; the right wing fuel vent was blocked with dried mud. 2 fuel tanks were found ruptured due to negative pressure. Furthermore; the hydraulic motor was found to be 'burnt' and the motor circuit breaker normally rated at 30 amps didn't trip until 70 amps. The p-lead on 1 rear engine magneto was found to be broken. On the first discrepancy; the pilot pointed out that a tube extending from the right wingtip was completely blocked with foreign material. I made a mental note to investigate the function of the subject tube. I had previously checked for blockage in a smaller tube under the same wing and incorrectly assumed that was the fuel vent tube. I also looked at another C337 of a different yr and did not see a tube extending from either wingtip; so I incorrectly assumed the tube in the subject aircraft was left over from a previous modification. About this same time; several other discrepancies surfaced that delayed the pilot from taking the aircraft at the previously scheduled time and I simply forgot to research the reason for the tube protruding from the wingtip. On the second discrepancy; the inspection checklist requires jacking the aircraft and retracting and extending the gear at least 5 times and timing the cycles. The cessna manual limit was 12-16 seconds. I recorded cycle times of 12-13 seconds on gear down cycle; and 15-16 seconds on gear up cycle times. Therefore; in addition to checking for leaks; looseness; interference; etc; I determined the gear system was airworthy. On the third discrepancy; I checked the engine timing on the rear engine and reinstalled the p-lead as well as checked the ignition switch grounding during at least 1 engine run-up and was found airworthy.

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Original NASA ASRS Text

Title: A C337G SEVERAL FLT HRS AFTER BEING RELEASED FROM ANNUAL INSPECTION THE PLT RPTED FUEL STARVATION AND LNDG GEAR PROBS.

Narrative: AFTER COMPLETING AN EXTENSIVE ANNUAL INSPECTION; DATED JAN/SUN/05; OF A C337G; THE SUBJECT ACFT WAS RETURNED TO SVC. AFTER SEVERAL LCL FLTS; ONE OF WHICH WAS SEVERAL HRS LONG; THE ACFT WAS DEEMED READY TO RETURN TO ITS BASE IN CANADA. UPON ARR AT ITS FINAL DEST; THE PLT RPTED BACK TO US THAT HE HAD AN ENG FAILURE INFLT AND THE LNDG GEAR MOTOR CIRCUIT BREAKER OPENED 3 TIMES INFLT. UPON INSPECTION BY A LCL MECH; THE R WING FUEL VENT WAS BLOCKED WITH DRIED MUD. 2 FUEL TANKS WERE FOUND RUPTURED DUE TO NEGATIVE PRESSURE. FURTHERMORE; THE HYD MOTOR WAS FOUND TO BE 'BURNT' AND THE MOTOR CIRCUIT BREAKER NORMALLY RATED AT 30 AMPS DIDN'T TRIP UNTIL 70 AMPS. THE P-LEAD ON 1 REAR ENG MAGNETO WAS FOUND TO BE BROKEN. ON THE FIRST DISCREPANCY; THE PLT POINTED OUT THAT A TUBE EXTENDING FROM THE R WINGTIP WAS COMPLETELY BLOCKED WITH FOREIGN MATERIAL. I MADE A MENTAL NOTE TO INVESTIGATE THE FUNCTION OF THE SUBJECT TUBE. I HAD PREVIOUSLY CHKED FOR BLOCKAGE IN A SMALLER TUBE UNDER THE SAME WING AND INCORRECTLY ASSUMED THAT WAS THE FUEL VENT TUBE. I ALSO LOOKED AT ANOTHER C337 OF A DIFFERENT YR AND DID NOT SEE A TUBE EXTENDING FROM EITHER WINGTIP; SO I INCORRECTLY ASSUMED THE TUBE IN THE SUBJECT ACFT WAS LEFT OVER FROM A PREVIOUS MODIFICATION. ABOUT THIS SAME TIME; SEVERAL OTHER DISCREPANCIES SURFACED THAT DELAYED THE PLT FROM TAKING THE ACFT AT THE PREVIOUSLY SCHEDULED TIME AND I SIMPLY FORGOT TO RESEARCH THE REASON FOR THE TUBE PROTRUDING FROM THE WINGTIP. ON THE SECOND DISCREPANCY; THE INSPECTION CHKLIST REQUIRES JACKING THE ACFT AND RETRACTING AND EXTENDING THE GEAR AT LEAST 5 TIMES AND TIMING THE CYCLES. THE CESSNA MANUAL LIMIT WAS 12-16 SECONDS. I RECORDED CYCLE TIMES OF 12-13 SECONDS ON GEAR DOWN CYCLE; AND 15-16 SECONDS ON GEAR UP CYCLE TIMES. THEREFORE; IN ADDITION TO CHKING FOR LEAKS; LOOSENESS; INTERFERENCE; ETC; I DETERMINED THE GEAR SYS WAS AIRWORTHY. ON THE THIRD DISCREPANCY; I CHKED THE ENG TIMING ON THE REAR ENG AND REINSTALLED THE P-LEAD AS WELL AS CHKED THE IGNITION SWITCH GNDING DURING AT LEAST 1 ENG RUN-UP AND WAS FOUND AIRWORTHY.

Data retrieved from NASA's ASRS site as of January 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.