WPR15LA008

**This report was modified on June 1, 2017. Please see the docket for this accident to view the original report.** On October 10, 2014, at 0715 Pacific daylight time, a Piper PA-28-180, N32150, sustained substantial damage following a partial loss of engine power and subsequent off field landing 1 mile from the Bend Municipal Airport, Bend, Oregon. The private pilot and his passenger received minor injuries. During the landing the right wing separated from the airplane. The airplane was registered to the pilot who operated the airplane under the provisions of 14 Code of Federal Regulations, Part 91. Visual meteorological conditions prevailed for the flight, and no flight plan had been filed. The flight originated from Bend Municipal Airport at 0705. The pilot reported that, about 4 to 5 minutes after takeoff, while climbing to 6,000 feet mean sea level (msl), the engine started to "shake and roll" and that the engine rpm reduced from about 2,400 to 1,800. The pilot reversed course to return to the airport. He turned ON the carburetor heat and richened the fuel mixture which resulted in no improvement of engine power. The pilot added that the rpm then dropped to between about 1,300 and 1,200, which was insufficient to maintain altitude. As he approached the airport it became apparent that he was not going to make the runway, at which point he executed an off field landing. The landing area was flat hard ground populated with large pine trees and boulders. The landing sequence resulted in the landing gear and the right wing being separated from the fuselage. Weather information obtained from the Bend Municipal Airport Automated Weather Observation System (AWOS-3) for 0715 recorded wind from 160° at 5 knots, 10 statute miles visibility, the sky was clear, temperature was 7°C, dew point was 0°C, and altimeter was 30.14 inHg. The upper air sounding from MFR (Medford, OR) from 0500 on October 10, 2014, indicated probable carburetor icing from the surface through 6,500 to 7,000 feet msl (mean sea level), then again closer to 10,000 feet msl. These values indicate moderate to severe carburetor icing most of the way up to 10,000 ft. The Salem, OR, upper air sounding supports possible carburetor icing through about 4,000 feet msl. A Federal Aviation Administration inspector arrived on-scene and examined the airplane. He took a fuel sample from the airplane as the recovery crew defueled the airplane. The fuel sample was straw colored but was chemically tested to be consistent with 100 octane low lead (100LL) aviation gasoline. On February 18, 2015, the NTSB Investigator-in-Charge (IIC) examined the airplane. The right wing had been sheared off at the wing root by ground impact forces. There was a 24 inch diameter semicircular crush that extended aft into the center of the wing at the leading edge, outboard of the fuel tank, which separated the wing into two pieces. The fuel cap was present on the filler hole, and the fuel tank had a breach located at theoutboard leading edge of the tank. Recovery personnel reported that the tank was empty when they arrived on-scene. A hole was cut into the top of the fuel tank to view the fuel port finger screen, which was observed to be clear of any foreign matter or debris. The left wing had been detached from the airframe by recovery personnel. The wing tip exhibited impact crush damage. The aileron and flaps were present on the trailing edge of the wing. The fuel tank cap was present on the fuel filler port. Recovery personnel stated that they recovered 7 gallons of avgas from this tank during the wreckage recovery. The recovered fluid was examined and was observed to have properties consistent with 100 LL avgas (blue coloration with a petroleum odor). A hole was cut in the top of the fuel tank to view the fuel port finger screen, which was observed to be clear of foreign matter or debris. Impact damage had fractured the generator housing, and separated it from its forward mount. Impact damage to the air box/filter had pushed it into the carburetor. Carburetor heat control cable was not attached to the carburetor heat butterfly plate actuator arm, but the bolt and nut that attaches the cable to the butterfly plate arm was present. Both throttle and mixture control arms on the carburetor were bent, but the control cables were attached and functional. No damage was observed to any of the cylinders, oil pan, or engine accessories. The oil filter and the date 6/4/2014, was hand written with black ink on the surface. The top spark plugs were removed. All top plugs were connected to the left hand magneto harness. Cylinder numbers 2, 3, & 4 exhibited normal operating signatures according to the Champion check-a-plug chart. The number 1 top and bottom spark plug exhibited excessive black soot on the electrodes. The propeller was rotated by hand and thumb compression was achieved on all 4 cylinders, and the magneto impulse coupling 'click' could be heard. A bluish fluid was drained from the gascolator. The top spark plug leads were connected to the left hand magneto, the bottom spark plug leads were connected to an electronic ignition. An external fuel tank was plumbed into the right hand fuel line that feeds the fuel selector. Fuel flow to the carburetor was verified by draining fresh fuel from the gascolator. The airplane battery was connected to the leads, the auxiliary fuel pump was energized for 3 seconds and the fuel primer was pumped 5 times. After numerous attempts, the engine started and was run up to 2,500 rpm. Oil pressure was steady at 80 psi. The engine ran steadily at 2,500 rpm for a couple of minutes, and a magneto check was performed. The electronic ignition rpm drop was about 50 rpm, and the left hand magneto drop was about 200 rpm. The engine idled steady at 1,800 rpm.