NTSB Factual Report

On April 6, 2007, at 1145 Pacific daylight time, a Piper PA-32R-301T (Saratoga), N4379A, experienced an in flight fire shortly after takeoff from Lincoln Regional Airport/ Karl Harder Field, Lincoln, California, and the airplane was substantially damaged during a forced, off-airport landing. The pilot was operating the airplane under the provisions of 14 CFR Part 91 for the local personal flight. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed.

The pilot stated that after departing runway 15, the airplane climbed to approximately 1,000 feet above ground level. He noticed a puff of white smoke emit from the defrost vents. The pilot brought the nose of the airplane down and there was a fire on the right side of the engine. He elected to immediately return to the airport to land. As he rolled onto the base leg of the traffic pattern, he heard a "pop" noise and black smoke poured from underneath the cowling. The engine lost complete power and the pilot force-landed the airplane in a field.

The wreckage was examined on April 11, 2007, at Plain Parts, Pleasant Grove, California. The National Transportation Safety Board investigator, the Federal Aviation Administration accident coordinator, and representatives from New Piper Aircraft Company and Textron Lycoming were present.

The top and bottom cowlings were removed. The majority of the thermal damage was evident on the right side of the engine as viewed from the pilot's (left) seat. Investigators noted that the fuel injection line of the number 5 cylinder was disconnected at the fitting of the manifold assembly, located below the number 3 cylinder assembly. The b-nut was off the threads of the fitting and floating along the steel fuel line. The fuel line, b-nut, and fitting threads were visually undamaged. The fuel line b-nut was reassembled to the manifold assembly. The b-nut threaded onto the fitting without binding and was tightened as required. No other anomalies were noted.

At the time of the accident, the tachometer indicated 1,178.9 hours. Review of the maintenance records showed that the last annual inspection was performed on December 6, 2006, at tachometer time of 1,173.5 hours. During the annual inspection, the number 5 cylinder assembly was changed, corresponding to 5.4 hours prior to the accident. Since the annual inspection, no additional maintenance had been logged in the maintenance records.

According to the Textron Lycoming representative, there are no Textron Lycoming published torque values for the subject b-nut.

The National Transportation Safety Board investigator interviewed the aviation maintenance technician with inspector's authorization (AMT/IA) who inspected the last work completed on the airplane. He indicated that the aviation maintenance technician (AMT) performing the work used standard maintenance procedures as specified in the Textron Lycoming Overhaul Manual to change the number 5 cylinder. Following the work, the engine was run for 5 minutes. It was then brought through a full run up and to full power. No fuel leaks were noted. The AMT/IA stated that there was no Textron Lycoming specified torque value for the fuel lines, and they were tightened as required. After the work was completed, the AMT/IA performed the final inspection and the airplane was signed off as airworthy.

NTSB Probable Cause

An in-flight fire occurred during the initial climb as a result of the aviation maintenance technician's failure to sufficiently tighten the b-nut that was found disconnected post-accident. A contributing factor was the engine manufacturer's failure to specify a torque value.