On June 20, 2011, about 1240 mountain daylight time, a Cessna 402, N3278Q, impacted the terrain after a rejected takeoff at Caldwell Independent Airport, Caldwell, Idaho. The commercial pilot and one of his passengers received minor injuries, and the remaining seven passengers were not injured. The airplane, which was owned and operated by the pilot, sustained substantial damage to its fuselage. The local 14 Code of Federal Regulations Part 91 skydiving flight, which was in the takeoff sequence at the time of the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, he taxied from the location where the airplane was normally kept, to the location where he picked up eight skydivers for the first drop of the day. After picking up the skydivers he taxied to the active runway where he completed the pre-takeoff checklist and engine run-up. He then initiated the takeoff roll, lifted off, and raised the landing gear. Just after he retracted the landing gear, the airplane's right engine experienced a complete loss of power. At that point, because there was still runway remaining, the pilot elected to abort the takeoff, and in order to keep the airplane upright, he pulled the throttle for the left engine to the idle position. Because he was very low over the ground, and he could not be assured of the timely extension of all three landing gear, the pilot decided not to extend the landing gear prior to the airplane settling back to the grass and dirt runway. During the process of touching down and sliding over the rough/soft terrain, the airplane's airframe became substantially damaged. After the accident the right engine was examined, to include the exhaust assembly, air induction assembly, magnetos and ignition assembly, spark plugs, fuel pump, fuel manifold valve, fuel lines and injection nozzles, air throttle assembly, fuel metering unit, lubrication system, oil filter, cylinders, rocker assemblies, accessory drive gear, alternator, and turbocharger. The examination did not reveal any anomalies that would have prevented the engine from operating and producing rated horsepower. After the removal of the drain plug from the right fuel tank in order to drain all of the remaining fuel, three pieces of what appeared to be latex-like thin film material were drained from the tank. One piece was cylindrical in shape, and the other two were flat sheets. All were irregular in shape, and all were seamless. All were translucent and light green/grey in color and very flexible. Each of the pieces was large enough by itself to block the 1.375 inch wide fuel boost pump inlet screen orifice, and all three pieces, when placed in a jar of 100 low-lead aviation fuel, sank to the bottom. It was not determined when or how the material had entered the fuel tank. After the initial on-scene examination, two of the three pieces were sent to the NTSB Materials Laboratory for further examination. The laboratory determined that the thickness of the material was 0.002 inches, and a Fourier Transform Infrared Spectrometer analysis determined that the material was most likely poly-isoprene. Poly-isoprene is also known as synthetic rubber.