N734SYCessna 172N

On August 29, 2024, about 1723 eastern daylight time, a Cessna 172N airplane, N734SY, was substantially damaged when it was involved in an accident near Lynchburg, Virginia. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight.

According to the pilot, the preflight inspection was normal, oil and fuel were at capacity, and the flight controls were free and correct. The preflight engine run was normal with the oil pressure indicating 60 psi, oil temperature was in the green arc, the magneto checks at 1,700 rpm showed normal rpm drops, and the carburetor heat check showed a normal rpm drop.

He then taxied to runway 10 at Falwell Airport (W24), Lynchburg, Virginia, for takeoff. All systems were normal. He added power for takeoff, the airspeed started to increase, and the tachometer read about 2,200 rpm. He then established an indicated airspeed of 80 kts during the initial climb. All systems were normal and indicated in the green arc. The oil pressure reading was above the middle of the green arc. Upon reaching about 1,300 ft above mean sea level, the engine lost all power. The pilot further described that the propeller stopped within 3 seconds. He then turned left, toward the departure airport, as he had seen a couple of open areas over his left shoulder.

At this time, he was communicating on the common traffic advisory frequency, where he made “Mayday” distress calls. He then picked an open area behind a hotel to attempt an emergency off-field landing. As he approached the open area the left wing hit a tree, which yawed the airplane 90 degrees. The airplane then impacted the ground and bounced before impacting the ground again and sliding to a stop. The pilot stated that he contacted his employees to bring a 55 gallon barrel to the scene so that they could remove the fuel that was slowly leaking from a fuel tank.

Postaccident examination of the airplane revealed that it was substantially damaged. The fuselage was intact with buckling and wrinkling on the right side, both aft of and below the passenger door. Control cable continuity from the rudder and elevator were established to the cockpit. The right wing displayed impact damage to the outboard portion of the aileron, and the aileron moved freely. Skin buckling consistent with impact forces was visible on the wing on the outboard forward, bottom surface. The left wing was wrinkled and bent in several locations. Crush damage to the leading edge was apparent over most of the wing. The left aileron was substantially damaged.

The cockpit was mostly undamaged. The primer was in and locked. The master switch was in the Off position. The ignition was in the Off position. There were no tripped circuit breakers observed. The carburetor heat lever was in the off position. The throttle and mixture control levers were observed in an idle and idle-cutoff position, respectively. The fuel selector was in the Off position.

Examination of the propeller revealed that, one blade was straight and undamaged. The second blade was bent slightly aft. No rotational signatures were observed on the propeller.

The fuel system fed from the high-wing fuel tanks, through the fuel selector, to the airframe fuel strainer, then directly to the engine carburetor. Compressed air was blown through the fuel selector in the Off, Right, Left, and Both positions and no discrepancies were noted. The fuel strainer contained a fine, sandy material in the bottom of the bowl that had a red tint in color. Fuel remained in the fuel strainer. The remaining fuel was tested with water-finding paste and no water was present. The inlet to the carburetor was clean. The carburetor was secured to the bottom of the engine sump housing and was undamaged. The carburetor was opened for further investigation. Minor debris was found in the bottom of the carburetor bowl. The main jet was clear. The plastic floats were undamaged.

All spark plugs remained installed in their respective cylinder heads and were undamaged. The top spark plugs were a combination of massive and fine wire electrodes. The bottom spark plugs were all fine wire electrodes. All spark plugs displayed coloration consistent with normal engine operation. The top spark plugs were bench tested and all four produced a bright blue spark.

The cylinder intake pipes were secured and undamaged from the sump housing to their respective cylinder heads. The No. 3 cylinder intake tube was removed and no blockage or debris was found within the engine sump housing. The engine air bracket filter was crush-damaged but appeared to be clean. The air hose from the bracket filter housing to the carburetor was crushed consistent with impact forces.

The heater muff was crush-damaged. Borescope examination of the muffler revealed no blockage; minor organic matter was observed at the tailpipe. There were no exhaust leak signatures noted.

The ignition harness was undamaged, and the leads were run to their appropriate cylinder locations from the dual magneto.

Continuity from the front of the engine to the rear accessory gears was confirmed. Thumb compression and suction were present on all four cylinders. Examination with a lighted borescope did not reveal any anomalies and the intake and exhaust valves were undamaged.

The oil filter had a large quantity of oil that was consistent with engine assembly oil. Minor amounts of ferrous/non-ferrous metal were found in the filter. The suction screen was not present within the oil sump. The oil pump was removed and no evidence of rotational scoring was observed within the pump. The oil passages were checked with safety wire and no blockages or obstructions were observed. The oil pressure relief valve ball was clean. No nicks or indents on the ball or seat were observed. The oil cooler bypass valve displayed a uniform seating witness mark. The oil sump contained about 5 quarts of clean engine oil.

A review of the airplane’s maintenance records revealed that the engine was overhauled on July 18, 2022. On June 29, 2023, when the engine had 144.8 hours time between overhaul (TBO), all four cylinders were removed and disassembled for valve work. A logbook entry on August 9, 2024, when the engine had 246.9 hours and 709.5 hours on the tachometer since overhaul, stated that “engine re-assembled” with overhauled cylinder assemblies, and the engine was then returned to the owner for installation; no engine test run was performed. On August 23, 2024, still with 246.9 engine hours and 709.5 tachometer hours since overhaul, the engine was again overhauled as a result of “no oil pressure” and the TBO was reset to 0. No explanations to the “no oil pressure” or reasons for the other engine work were provided within the maintenance documentation.

The Cessna 172 preflight inspection checklist includes a reminder to “check for contamination while draining fuel from fuel strainer.”