CEN23LA388

The flight instructor and private pilot receiving instruction reported that their first two attempts to depart were aborted due to engine roughness discovered during the engine run-ups, which was subsequently determined to be an ignition issue that was addressed by replacing a spark plug. After a satisfactory engine run-up check, they initiated the takeoff. During the initial climb, when the airplane reached about 150 ft above ground level (agl), the tower controller informed them that the airplane was trailing smoke. About that time, the engine lost all power, and the flight instructor executed a forced landing to a field where the airplane sustained substantial damage to both wings, fuselage, and left horizontal stabilizer. Postaccident examination revealed that the oil sump contained only 4 quarts of oil with a total oil capacity of 12 quarts. No evidence of an external oil leak was found. Examination of the top spark plugs found that the electrodes were dry, black, and sooty, indicating an overly rich fuel mixture. The airplane was equipped with a fuel flow transducer installed at the firewall, upstream of the engine driven-fuel pump and downstream of the electric fuel pump. According to the maintenance records, the transducer was installed in conjunction with an avionics upgrade and in accordance with a supplemental type certificate (STC). The installation manual associated with that STC stated that the placement of the transducer was at the discretion of the installer but that a common location was downstream of any electric boost pumps but upstream of the engine-driven fuel pump. However, the transducer manufacturer’s installation manual provided conflicting information, stating that the transducer must be installed after any fuel pumps and that installation upstream of any fuel pumps could result in vapor lock. Although a vapor lock condition would result in a lean mixture that could result in a loss of engine power, the spark plug indications and the in-flight smoke were not indicative of a lean mixture condition. Additionally, although vapor lock can result in hard starting, it generally does not manifest as a loss of power once the engine is operating. The oil sump contained less oil than specified for its minimum operating capacity. However, postaccident examinations found no evidence of oil leakage and no condition that would result in the engine burning oil. Further, the engine was not seized, and the spark plugs did not appear to be oil fouled. Thus, there was no evidence that the low oil level contributed to the loss of engine power. A fuel line fitting that extended from the engine-driven fuel pump to the mixture valve was loose and moved freely when slight finger pressure was applied. Blue staining was evident at the fitting location, potentially consistent with fuel leakage. The fuel injection mixture control valve screen contained substantial debris and fibers. However, postaccident testing of the fuel control unit (with thecontaminated screen installed), fuel pump, and fuel flow sensor revealed no functional deficiencies. The loose fuel fitting could result in leakage of fuel and, in conjunction with the obstructed fuel filter, could result in a lean mixture. Under certain conditions, fuel leakage in an airplane can result in a fuel spray that may appear as a cloud of white fuel vapor, which could be mistaken for smoke. However, the investigation was not able to determine the amount of fuel leakage from the loose fitting, and, as stated previously, the spark plug indications were inconsistent with a lean fuel condition. The reason for the loss of power could not be determined.

On August 30, 2023, about 1314 central daylight time, a Cessna 210B airplane, N9663X, sustained substantial damage when it was involved in an accident near the Wichita Dwight D Eisenhower International Airport (ICT), Wichita, Kansas. The pilot, flight instructor, and passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor and private pilot receiving instruction both reported that they twice attempted to depart previously but that each time, the pretakeoff engine run-up revealed engine roughness during the magneto checks. Both times, they returned the airplane to a maintenance facility for diagnosis. Ultimately, one of the engine’s spark plugs was replaced, and the subsequent pretakeoff engine checks were satisfactory. The final engine run-up was performed near the maintenance hangar where the work was performed and was followed by a long taxi to the takeoff runway. The flight instructor and the pilot reported that, during the accident takeoff, as the airplane was climbing through about 150 ft agl, the ICT tower air traffic controller advised them that he saw smoke coming from the airplane. About that time, the airplane’s engine lost all power, and the flight instructor executed a forced landing to a field north of the runway. During the landing, the airplane struck a ditch, and the nose landing gear and left main landing gear separated from the airplane. The airplane sustained substantial damage to the fuselage, both wings, and horizontal stabilizer. Postaccident examinations revealed no evidence of a fire or any external oil leakage. All of the top spark plugs were removed from the engine and exhibited a dry, black, sooty appearance consistent with an overly rich fuel mixture. The engine contained 4 quarts of oil. The total oil sump capacity was 12 quarts with a specified minimum operating capacity of 9 quarts. A fuel line fitting that extended from the engine driven fuel pump to the mixture valve was loose and moved freely when slight finger pressure was applied. Blue staining was evident at the fitting location. The fuel injection mixture control valve screen contained substantial debris and fibers. Fuel sumped during the examination was blue in color and clean. The main fuel strainer contained a slight amount of debris. Both magnetos exhibited spark on all leads when actuated. Engine compression was observed when the engine was rotated through and engine controls were continuous from the cabin outboard to the engine. The outer portion of the propeller blades were bent aft about 45 degrees. Neither blade exhibited S bending, or leading edge damage. The cambered side of each blade exhibited polishing where the blade was bent. The airplane was equipped with a fuel flow transducer that was mounted to a bracket on the firewall in a horizontal position with its wires facing up. The location of the transducer placed it in the fuel system upstream ofthe engine-driven fuel pump. The transducer was connected to flexible fuel lines that were unsupported. According to the maintenance records for the airplane, the transducer was initially installed on August 3, 2022, but relocated on March 21, 2023, during the airplane’s most recent annual inspection. The records stated that the relocation was performed in accordance with STC SA02594SE revision M. Review of the STC indicated that the installation was to be completed in accordance with Dynon Avionic System Installation Manual, Document Number 103261-000, Revision M, dated January 19, 2022, or later FAA-approved revision. The fuel flow transducer installation section of Revision S of this installation manual stated the following: • Do not install the fuel flow transducer, hoses, and fittings near exhaust system or turbocharger. Excessive heat can damage fuel system components. • Do not install 90° fittings (elbows) on the input or output of the fuel flow transducer. Doing so will cause turbulence in the fuel flow which causes inaccurate fuel flow data. • Install the fuel flow transducer with the three wires pointed UP. • Install a fuel filter UPSTREAM of the fuel flow transducer to screen out debris. • For best measuring performance, the fuel should travel uphill by 1 to 2 inches (2.54-5.08 cm) after leaving the fuel flow transducer. • Placement of the fuel flow transducer is dependent upon other components in the fuel system lek fuel pumps is left to the builder. It is common to place the sensor downstream of any auxiliary electric boost pumps but upstream of the engine driven fuel pump. A review of the installation manual from the transducer manufacturer revealed the following: “If the aircraft has a fuel pump(s), the flow transducer MUST be installed downstream of the last fuel pump. Installing the transducer upstream of the fuel pump(s) can cause vapor lock and jumpy inaccurate readings.” The manual further stated that the fuel flow transducer: “…should not be installed with the wires pointing DOWN (the best situation is with wires pointing UP). Also, the fuel line on the outlet port should not drop down after exiting the transducer. Both of these configurations can trap bubbles in the transducer causing jumpy readings. The inlet port, outlet port and flow direction are marked on the top of the…[transducer]. This transducer must be suspended between flexible hoses on the inlet and exiting ports. The hoses must be supported within 6 inches of the transducer.” Postaccident functional testing of the fuel pump, fuel control unit, and fuel transducer on a calibrated flow bench did not reveal any deficiencies. The contaminated fuel screen was installed during the functional testing. The pilot, who was a part owner of the airplane, stated that other pilots of the airplane told him that the fuel pressure indication could be jumpy at times and would go to red line during takeoff. The reported erratic indication could not be replicated duringpostaccident examination and testing.