WPR18LA034

The pilot's delayed decision to execute an emergency landing and his attempt to return to the airport following a partial loss of power due to wear on internal engine components, which prevented the engine from developing full-rated power during the airplane's initial climb.

The pilot reported that during the takeoff for the personal flight, as the airplane reached about 50 ft above ground level, the airplane stopped climbing and the pilot was unable to maintain altitude. When the airplane stopped climbing, the pilot and pilot-rated passenger decided to examine the anomaly further as the pilot began a wide, shallow left turn and attempted to maintain altitude. A video showed that as the airplane completed the turn, it entered a steep bank angle and descended. The airplane's wings leveled out just before the airplane disappeared behind trees and impacted a trailer, trees, and a residence, which resulted in substantial damage to the wings, empennage, and fuselage. Examination of the area revealed that, had the pilot initiated an emergency landing straight ahead rather than troubleshooting the engine problem or attempting to return to the airport, the damage may have been reduced. Postaccident examination of the engine revealed the travel of two of the intake valve rockers was severely limited, the camshaft lobe that supported these intake valves was severely worn and had extensive pitting, and spalling damage was on the faces of the camshaft lifters supporting these intake valves. The decreased travel of the intake valves would have reduced the fuel/air mixture reaching the affected cylinders, thus reducing the overall power the engine could produce. A review of maintenance records revealed that owner had not complied with a manufacturer's mandatory service bulletin requiring a rocker arm inspection. While a service bulletin is not mandatory for Part 91 airplane owners, compliance with the service bulletin might have revealed the limited travel of the rocker arms and prevented the loss of engine power.

Narrative medical and pathological information place holder Narrative meteorological information place holder Narrative personal information place holder The airplane impacted a trailer and several small trees before it collided with the front of a residence and came to rest in the front yard. All three landing gear had collapsed or separated from the fuselage, which was resting flush against the ground. The outboard portion of the left wing was separated and the right wing was partially separated about mid-span. The empennage displayed some buckling at the aft fuselage. Aircraft Examination Flight control continuity was traced from the cockpit to the elevator, rudder, and ailerons. The left aileron cable and through cable were both fractured in tensile overload at the aileron-flap junction. The wing flap actuator was not extended, consistent with a flap retracted position. Continuity of the mixture and throttle controls were confirmed from the cockpit to their respective arms on the fuel control unit; however, damage to the throttle and mixture control inhibited their full range of movement. The stall warning horn did not display any anomalies. Several ounces of fuel that resembled 100 low lead aviation grade gasoline were drained through the fuel strainer, which did not present any contamination or debris. Fuel line continuity was confirmed from the door posts to the fuel selector valve, which moved normally through each of its detents. The top spark plugs were removed and thumb compression and suction was obtained for all four cylinders and in the proper firing order. Mechanical continuity was established throughout the rotating group, valve train and accessory section as the engine was manually rotated at the propeller. For this particular engine, the intake valves of opposing cylinders share a common camlobe. The engine was rotated once more with the rocker covers removed, which showed inhibited movement for the intake valves to cylinder nos. 3 and 4, as they did not extend to their full travel positions. A subsequent examination after the engine was disassembled revealed that the camshaft lobe supporting the intake valves to these cylinders was severely worn with extensive pitting, a condition that is known to develop over time. Additionally, the lifters for both intake valves were spalled. Additionally, the camshaft lobe that supports the intake valves for cylinder nos. 1 and 2 exhibited some wear and the lifters were spalled. The combustion chambers remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The engine spark plugs were gray in appearance, consistent with normal wear when compared to the Champion Aerospace Aviation Service Manual. Both magnetos remained attached to the engine accessory case and all 8 ignition harness leads displayed normal wear and exhibited spark when the propeller was rotated by hand. The propeller remained attached to the propeller flange and the engine. One blade exhibited chordwise scratches, blade tip curling and the blade tip was separated. The other blade displayed a gouge and bending at the tip, which had separated. Carburetor Examination The carburetor, which had separated from the engine case, was examined by the manufacturer with oversight from a representative of the Federal Aviation Administration. A flow test was not performed due to the physical damage the unit incurred during the impact. Further, the unit could not be evaluated for operational anomalies due to the damage on the casting, throttle, venturi, and mounting features. The examination revealed no evidence of debris or contamination in the needle valve seat or accelerator pump check valve. The needle valve was intact, the main jet was clean and undamaged and the float met the manufacturer's clearance specifications. The airplane was powered by a Lycoming O-320-D2J, air cooled, 160 horsepower engine. Maintenance records indicated that the airplane's most recent 100 hour engine inspection was completed on November 4, 2017, at a total time of 14,748.3 flight hours and a tachometer time of 1,756.4 hours. At the time the engine had accrued a total of 2,151.5 flight hours since its most recent engine overhaul, which was accomplished 2,173 flight hours prior to the accident. According to the airplane's tachometer, at the time of the accident, the engine had accrued 1,779 hours total time in service and 22 flight hours since the airplane's most recent inspection. The logbook records showed that the no. 3 cylinder had been replaced 171 hours prior to the accident. Additionally, the flight school owner and maintenance director reported that his maintenance team applied PRC to the no. 2 cylinder to stop a "nuisance oil leak", which required them to remove and re-install the no. 2 cylinder. The flight school owner further reported that they had a planned to replace the engine after the accident flight. Magneto Check According to the "Magneto Check" excerpt from the pilot's operating handbook (POH), the engine rpm drop observed should not exceed 125 rpm on either magneto or show greater than a 50 rpm differential between magnetos. The excerpt states that if there is a doubt concerning operation of the ignition system, the rpm checks should be performed at higher engine speeds to confirm if there is a deficiency. Emergency Procedure - Loss of Power The Emergency Procedure section of the POH contains the procedural steps below for executing an emergency landing without engine power. Airspeed – 65 KIAS (flaps up); 60 KIAS (flaps down) Mixture – Idle Cut-off Fuel Selector Valve – OFF Ignition Switch – OFF Wing flaps – As Required (30° recommended) Master Switch – OFF Doors – Unlatched prior to touchdown Touchdown – Slightly tail low Brakes – Apply heavily Engine Failure The Emergency Procedure section of the POH also includes a discussion about engine failures. Prompt lowering of the nose to maintain airspeed and establish a glide attitude is the first response to an engine failure after takeoff. In most cases, the landing should be planned straight ahead with only small changes in direction to avoid obstructions. Altitude and airspeed are seldom sufficient to execute a 180° gliding turn necessary to return to the runway. On November 19, 2017, about 1500 Pacific standard time, a Cessna 172P airplane, N52492, was substantially damaged when it was involved in an accident in San Jose, California. The private pilot sustained minor injuries and the two passengers were seriously injured. The airplane was operated by Squadron 2 Flight Club as a Title 14 Code of Federal Regulations Part 91 personal flight. During the accident flight, the pilot was seated in the front left seat and the pilot-rated passenger was seated in the front right seat. A passenger was seated in the row 2 left seat, behind the pilot. The front seat occupants had agreed that the pilot would fly the airplane while the pilot-rated passenger made radio calls and verified checklist items. They computed the airplane's weight and balance, takeoff distance and roll with full fuel tanks. After a preflight inspection, they taxied the airplane to the airport run-up area. The pilot ran the engine up to 1,800 rpm and observed a 50 rpm drop when she selected the right and left magnetos individually, during which time she observed a difference of 75 rpm between the magnetos. The pilot reported that she followed the airplane checklist for each procedure, then selected both fuel tanks and departed after she received a clearance from air traffic control. She did not deploy the flaps during the accident flight. The instrument indications were in the green as the airplane lifted off the runway at 55 knots. During the initial climb, to about 50 ft indicated altitude, the pilot observed a decreasing climb rate and airspeed with a simultaneous drop in rpm. Th