WPR15FA181

The partial loss of engine power during takeoff due to debris within the fuel servo, which restricted fuel flow throughout the engine fuel system and resulted in a partial loss of engine power.

The pilot receiving instruction reported that following a normal taxi and pre takeoff engine run up, the flight instructor initiated the takeoff sequence for a local instructional flight. He noted that during the takeoff, the flight instructor retracted the landing gear and the airplane began a slow climb, however, it seemed like the airplane had no power to climb. The pilot receiving instruction further stated he saw the flight instructor managing the fuel and verifying the throttle position as the airplane began to descend. Subsequently, the airplane impacted a grassy wetland area on the departure end of the runway. Postaccident examination of the airplane revealed erratic fuel flow from the fuel nozzles. Further examination of the engine revealed that the fuel servo inlet fuel screen was installed 180-degrees opposite of the manufacturer's installation instructions, which would allow for unfiltered debris to flow throughout the fuel system. The engine was installed on a test cell and during the first 5 engine run attempts, it was noted that the engine was not firing on all cylinders, and would not produce rpm over 1,500. The fuel servo unit was removed and a carburetor was subsequently installed. The engine started and ran successfully at various power settings for about 23 minutes prior to being shut off utilizing the engine test cell fuel shut off. Disassembly of the fuel servo revealed a significant amount of debris in two of the fuel diaphragm housings, and on the diaphragm assemblies, one of which regulates fuel to the fuel injectors. The mixture control valve and idle valve exhibited evidence of corrosion. The idle valve was found seized within its respective galley. Upon removal, corrosion was observed within the galley. The debris observed within the fuel servo was removed and visually, the debris was composed of two optically different particle types. The debris was predominately larger grey white particles mixed with lesser amounts of smaller dark brown particles. X-ray fluorescence spectrometer examination of several different areas of the grey white particles indicated compositions consistent with aluminum alloys. The white appearance and crumbling nature of the particles was indicative of heavily oxidized aluminum. Spectra of the dark brown particles were consistent with low alloy steels. The appearance and dark color was indicative of heavy oxidization of the particles. The source of the debris within the fuel servo and whether the misinstalled fuel screen allowed the debris to enter the servo could not be determined. It is likely that the debris within the fuel servo was distributed throughout the engine fuel system, which allowed for restricted fuel flow to each of the fuel injectors, which would result in an erratic running engine and partial loss of engine power.

PAE is a tower controlled airport that operates under class Delta airspace. The airport is equipped with two runways, 16R/34L, which is 9,010 feet in length and 150-feet wide and 16L/34R, which is 3,004 feet in length and 75-feet wide. The reported field elevation for the airport is 607 feet. The distance from the Alpha 4 taxiway and the departure end threshold of runway 16R is about 5,200 feet. Further examination of the engine was conducted at Continental Motors Inc., Mobile, Alabama, on November 18, 2015. The examination revealed that the engine was received secure within its crate. The propeller and propeller governor were removed and a test propeller was installed to facilitate the engine run. The fuel servo inlet fuel screen was removed for inspection. The screen was found to be installed 180-degrees opposite of the manufacturer's installation instructions. This would allow for debris to flow throughout the system, unfiltered. About one-quarter to one-half of a teaspoon of dark colored debris was removed from the fuel screen and fuel screen housing. In addition, corrosion was observed within the fuel screen and the fuel screen housing cap. The engine was placed on an engine test cell. During the first 5 engine run attempts, it was noted that the engine was not firing on all cylinders, and would not produce RPM over 1,500. Despite replacing the top spark plugs, changing magneto to engine timing (from 31 to 27 degrees), and switching the fuel flow divider, the engine continued to run on partial cylinders. The fuel servo unit was removed and a carburetor was subsequently installed. The engine was started and ran successfully at various power settings (maximum of 2,550 rpm) for about 23 minutes prior to being shut off utilizing the engine test cell fuel shut off. The fuel system, which includes the fuel flow divider, fuel servo, and fuel nozzles were removed and retained for further examination at Precision Air Motive. Examination of the fuel system was conducted on January 4, 2016, at the facilities of Precision Air Motive, Arlington, Washington. The fuel servo was disassembled and examined. A significant amount of debris was noted in two of the fuel diaphragm housings, and on the diaphragm assemblies, one of which regulates fuel to the fuel injectors. The mixture control valve and idle valve exhibited evidence of corrosion. The idle valve was found seized within its respective galley. Upon removal, corrosion was observed within the galley. All debris found appeared to be either a pliable gray material, similar to a paste, or a brittle white material, similar to aluminum oxide corrosion. The debris observed within the fuel servo was removed and subsequently sent to the NTSB Materials Laboratory for further examination. The submitted debris from the fuel servo was visually examined and selected particulates were analyzed using a hand held X-ray Fluorescence Spectrometer (XRF). Visually, the debris was composed of two optically different particle types. The debris was predominately larger grey white particles mixed with lesser amounts of smaller dark brown particles. XRF spectra of several different areas of the grey white particles indicated compositions consistent with aluminum alloys. The white appearance and crumbling nature of the particles was indicative of heavily oxidized aluminum. Spectra of the dark brown particles were consistent with low alloy steels. The appearance and dark color was indicative of heavy oxidization of the particles. The source of the debris within the fuel servo was not determined. The airplane was equipped with a JPI EDM 700 engine monitoring unit. The data downloaded from the unit revealed that on the accident flight, the recorded data spanned about 19 minutes. The data showed a rise in exhaust gas temperatures (EGT) and cylinder head temperatures (CHT) for all cylinders followed by two separate decreases in the EGT recordings, consistent with an engine run up. The data further depicted that the EGT values began to be erratic about 13 minutes following the start of the recorded data. The cylinder 5 EGT value showed a decrease from about 1,400 degrees F to about 400 degrees F over the course of about 1 minute prior to increasing back to about 1,400 degrees F and a decrease in CHT from 360 degrees F to about 270 degrees F. For further information, see the JPI Engine Monitoring Unit data plot within the public docket for this accident. The Snohomish County Coroner conducted an autopsy on the flight instructor on June 11, 2015. The medical examiner determined that the cause of death was "blunt-force injuries of the head and chest." The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the flight instructor. According to CAMI's report, carbon monoxide, cyanide, volatiles, and drugs were tested, and had positive results for: 39 (ug/ml, ug/g) Acetaminophen detected in Urine, Ibuprofen detected in Urine, Terazosin detected in Urine, Terazosin detected in Blood (Cavity), Warfarin detected in Blood (Cavity) and Warfarin detected in Urine. Examination of the accident site revealed that the airplane impacted an area of heavy vegetation about 1,921 feet south of the departure end of runway 16R. The airplane came to rest upright on a heading of about 230 degrees magnetic. The first identified point of contact with terrain was disturbed vegetation within a marshy area, which extended about 88 feet to the main wreckage, oriented on a heading of about 160-degrees magnetic. Examination of the airframe revealed that the engine remained attached to the fuselage and was slightly displaced downward. All fuel and oil lines remained attached to their respective attach points. The left wing remained attached to the fuselage via its mounts. The flap and aileron remained attached to their respective mounts. The left wing was bent downward about 5 feet inboard from the wing tip on the leading edge. 45-degree buckling extended from the leading edge to the trailing edge, about 44 inches inboard from the wing tip. The wing tip tank, aux, and main fuel tank caps remained intact and secure to the fuel tanks. The trailing edge of the left wing tip was punctured and the first responders sealed it with sealing putty. The left main fuel tank sump drain was separated from the bladder. The flap was in the up position. The right wing remained attached to the fuselage via its mounts. The flap and aileron remained attached to their respective mounts. The right wingtip fuel tank was impact damaged and separated in half. The wing tip tank, aux, and main fuel tank caps remained intact and secure to the fuel tanks. Multiple leading edge impact marks were observed. The flap was in the up position. The fuselage above the carry through structure exhibited vertically oriented buckling, and the fuselage on the right side exhibited horizontal buckle lines. The rear fuselage was buckled downward between fuselage stations 151 and 179. The remainder of the rear fuselage and empennage remained intact. Flight control continuity was established from the cockpit controls to all primary flight control surfaces. Pitch control was able to be manipulated from the cockpit controls. The rudder pedals could not be moved due to floorboard impact damage. Both aileron and rudder control cables were found pinched by floorboard impact damage as they passed under the front carry through. The landing gear was found in the "up" position. The landing gear actuator was in the retracted position and the cockpit landing gear handle was in the up position. The cockpit was intact with the interior space not compromised. The left and right seats were equipped with lap belt restraints only. The left seatbelt was clasped, and the outboard side of the seatbelt was cut. The right side seatbelt was unclasped. No shoulder harnesses were installed. The left and