Accident Details
On July 7, 2017, at about 0735 eastern daylight time, a Cessna T337D (registration N337J) was substantially damaged during a forced landing near Greenwood County Airport (GRD) in Greenwood, South Carolina. The flight instructor and a private pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight. The airplane was operated under 14 Code of Federal Regulations Part 91.
Sequence of Events
The flight instructor reported that the purpose of the flight was for the single-engine rated private pilot (student) to become familiar with the accident airplane as he worked toward an instrument rating. The private pilot performed the preflight inspection with no anomalies noted. The flight instructor stated that their inspection of the fuel tanks revealed they were ¾ full, verified on the airplane's fuel gauges. The student stated that during preflight they did not visually check the fuel tanks but noted the fuel gauges read between ½ and ¾ full. The engine run-up was normal, and they departed from runway 27.
After departure, they practiced maneuvers uneventfully for about 30 minutes and then performed one aerodynamic stall. After practicing the stall, the front engine started to surge from high to low power and then lost all power. The flight instructor told the pilot to turn back to the airport while he consulted the emergency checklist for the engine-out procedure. The rear engine was still operating normally. The flight instructor turned on the fuel boost pump, switched the fuel tank from main to auxiliary and back to main in an attempt to restore power to the front engine, to no avail. He recalled that sometime during the return flight, the rear engine also experienced a total loss of power. The airplane was too low to reach the runway, so the pilot transferred control to the flight instructor, who performed a forced landing into trees.
Post-Accident Examination
Examination by a Federal Aviation Administration (FAA) inspector revealed that the airplane came to rest on its right side. The right wing separated from the fuselage and was found inverted on the fuselage. The left wing and strut remained attached. A fuel sample from the left wing auxiliary sump was blue and absent of visible debris. The right-wing fuel tanks were not accessible. The salvage crew stated they removed 6 gallons of fuel from the left wing and no fuel from the right wing. The FAA inspector noted no smell of fuel at the accident site. Both wings had impact marks consistent with hitting trees. The front and rear engine propellers did not exhibit rotational scoring. The landing gear were extended.
Examination of both engines revealed evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. The four main fuel tank fuel quantity sender units were removed and tested with an ohm meter. In the empty position, the left outboard fuel sender had a resistance value equal to an approximately half-full reading. The left and right inboard fuel senders had a resistance value equal to an approximately full tank reading. The right outboard fuel sender unit displayed inconsistent resistance readings throughout its range of travel.
The airplane was equipped with a main fuel tank in each wing and an auxiliary fuel tank in each wing, totaling 131 gallons (128 usable, 3 unusable). Each main fuel tank consisted of two metal tanks (outboard and inboard) connected with hoses; fuel flowed from the outboard to inboard via gravity. Each main tank had two float-type fuel level sender units (one in each outboard and inboard), connected electrically in parallel to a cockpit fuel quantity gauge.
Maintenance History
On November 29, 1999, the airframe manufacturer released mandatory Service Bulletin MEB99-21, applicable to several models including the accident airplane. The bulletin aimed to inspect the Stewart Warner fuel quantity indicating system to verify that each fuel tank gauge indicates empty when the tank contains only unusable fuel and full when the tank is full. The bulletin required an initial inspection within 100 hours of operation or 12 months, whichever occurred first, and subsequent recurrences every 12 months.
The airplane's most recent annual inspection was completed on February 24, 2017, at 2,591 total airframe flight hours. Review of the airplane's maintenance logbooks revealed no evidence that MEB99-21 had been complied with.