N8740EPiper PA-28-181 · 1976

On July 19, 2015, about 1320 Pacific daylight time, a Piper PA-28-181, N8740E, collided with terrain minutes after departing Henderson Executive Airport, Las Vegas, Nevada. The private pilot and three passengers were seriously injured, and the airplane was destroyed by a postaccident fire. The airplane was registered to the private pilot, and operated as a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed for the flight, and a flight plan had not been filed. The flight originated from Las Vegas about 1330, and was destined for San Diego, California.

The pilot reported that the takeoff seemed normal, but once airborne the airplane's climb was "sluggish" and the engine's rpm's at 200-300 rpm lower than normal. He was able to maintain straight and level flight about 300 feet above ground level (agl). When the pilot made a left-hand turn in an attempt to return to the airport, the airplane immediately began to lose altitude. The pilot selected a landing site, and executed a forced landing into an open area associated with a construction site. During the landing sequence into uneven terrain, the landing gear was torn off, and the airplane caught fire. As soon as the airplane came to rest, the front passenger door was opened and the occupants evacuated the airplane. The airplane was consumed by the postaccident fire.

The tower controller at Henderson Airport reported that the airplane appeared to not be climbing normally after takeoff, and he cleared the pilot to make any maneuvers necessary to return to the airport if he desired. A witness reported that he observed the airplane takeoff and struggle to gain altitude; it then made a left turn followed by a steep bank turn and crashed. The airplane crashed into an open construction site and the occupants egressed the airplane before it was completely engulfed in fire.

The airplane's official weight and balance record was contained in the airplanes maintenance records. Using information from a PA-28-181 Pilot's Operating Handbook, the following was used to estimate expected airplane performance. The pilot reported having 30 gallons (180 lbs) of fuel onboard at the time of takeoff, and the estimated combined weight of all the occupants was 770 lbs. The empty weight of the airplane was 1502.5 lbs. and the listed maximum gross weight is 2,550 lbs. The calculated weight of the airplane at takeoff was 2,452.5 lbs. The airport elevation is 2,492 ft mean sea level (msl), the temperature was 33 C, and the pressure altitude was 30.10 inHg. The calculated density altitude for those conditions was 5,014 ft. Utilizing the climb performance chart for a PA-28-181 for these conditions resulted in an expected rate-of-climb of 520 feet per minute.

A review of the airplane's maintenance records revealed that the most recent annual inspection was performed on February 25, 2015, at a total airframe time of 4,040 hours. The mechanic who performed the annual inspection stipulated in the airframe logbook that the carburetor heat control bracket required repair, and that the number 2 navigation radio head required a placard indicating the radio was inoperative. Once those repairs had been made by an A&P mechanic then the entry stated, "this aircraft will be airworthy & ok for return to service." The A&P mechanic who performed the annual inspection stated to the NTSB investigator-in-charge (IIC) that he did perform the engine static rpm check as part of the annual inspection, during which he noticed that the rpm was 10% to 20% below normal. He attributed that reduction in rpm to the loose carburetor heat door which could allow the carb heat to be in an unknown position. Maintenance records obtained from First Flight Corp, San Diego, CA, documented that the carburetor heat bracket was repaired on March 5, 2015.

The engine, a Lycoming O-360-A4A, capable of producing 180-hp, was overhauled on October 6, 1986, and had accumulated 1,461 hours since the overhaul. The airplane and engine had accumulated a total of approximately 150.4 hours over the 10 years preceding the accident.

On July 23, 2015, the engine was examined by a technical representative of Lycoming under the oversight of a Federal Aviation Administration (FAA) inspector. During the examination, the top spark plugs were removed, examined, and photographed. The crankshaft was rotated by hand utilizing the propeller. The crankshaft was free and easy to rotate in both directions. "Thumb" compression was observed in proper order on all four cylinders. The complete valve train was observed to operate in proper order. Clean, uncontaminated oil was observed at all four rocker box areas. Investigators noted that each of the intake valve rockers exhibited limited movement estimated to be about 50% less than normal. The intake valves of opposing cylinders share a common cam lobe. To facilitate further internal examination, holes were drilled through the top of the engine case material in-line with the rotational plane of each connecting rod. A lighted borescope was inserted to visualize each of the cam lobes at the respective cylinder position. Visual examination confirmed signatures of excessive wear on the intake cam lobes. Mechanical continuity was established throughout the rotating group, valve train and accessory section during hand rotation of the crankshaft. The bottom spark plugs were not removed. The combustion chamber of each cylinder was examined through the spark plug holes utilizing a lighted borescope. The combustion chambers remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The valves were intact and undamaged. There was no evidence of valve to piston face contact observed.

The left and right magnetos remained securely clamped at their respective mounting pads and had been thermally damaged due to the effects of the post impact ground fire. The ignition harness was secure at each magneto. The magnetos were removed for examination. The magnetos sustained varying degrees of thermal damage that rendered the unit inoperative and therefore, could not be functionally tested. Magneto to engine timing could not be ascertained.

There was no oil residue observed in the exhaust system gas path. There was significant ductile bending of the exhaust system components. The exhaust system was found free of obstructions.

A subsequent teardown examination of the engine was conducted September 01, 2015, under the oversight of the NTSB investigator-in-charge. The engine was completely disassembled. The cylinder(s) combustion chambers and barrels remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The valves were intact and undamaged. There was no evidence of valve to piston face contact observed. The pistons were intact. The ring assemblies at each piston were intact and free to rotate within their respective ring land. Mechanical continuity of the rotating group and internal mechanisms were established visually during the disassembly and examination of the engine. The accessory gears including the crankshaft gear, bolt and dowel were intact and remained undamaged by any pre-impact malfunction. There was no evidence of lubrication depravation found. The crankshaft and attached connecting rods remained free of heat distress. The valve tappet faces exhibited significant spalling damage.

A review of the airplane's maintenance records revealed that the most recent annual inspection was performed on February 25, 2015, at a total airframe time of 4,040 hours. The mechanic who performed the annual inspection stipulated in the airframe logbook that the carburetor heat control bracket required repair, and that the number 2 navigation radio head required a placard indicating the radio was inoperative. Once those repairs had been made by an A&P mechanic then the entry stated, "this aircraft will be airworthy & ok for return to service." The A&P mechanic who performed the annual inspection stated to the NTSB investigator-in-charge (IIC) that he did perform the engine static rpm check as part of the annual inspection, during which he noticed that the rpm was 10% to 20% below normal. He attributed that reduction in rpm to the loose carburetor heat door which could allow the carb heat to be in an unknown position. Maintenance records obtained from First Flight Corp, San Diego, CA, documented that the carburetor heat bracket was repaired on March 5, 2015.

The engine, a Lycoming O-360-A4A, capable of producing 180-hp, was overhauled on October 6, 1986, and had accumulated 1,461 hours since the overhaul. The airplane and engine had accumulated a total of approximately 150.4 hours over the 10 years preceding the accident.

On July 23, 2015, the engine was examined by a technical representative of Lycoming under the oversight of a Federal Aviation Administration (FAA) inspector. During the examination, the top spark plugs were removed, examined, and photographed. The crankshaft was rotated by hand utilizing the propeller. The crankshaft was free and easy to rotate in both directions. "Thumb" compression was observed in proper order on all four cylinders. The complete valve train was observed to operate in proper order. Clean, uncontaminated oil was observed at all four rocker box areas. Investigators noted that each of the intake valve rockers exhibited limited movement estimated to be about 50% less than normal. The intake valves of opposing cylinders share a common cam lobe. To facilitate further internal examination, holes were drilled through the top of the engine case material in-line with the rotational plane of each connecting rod. A lighted borescope was inserted to visualize each of the cam lobes at the respective cylinder position. Visual examination confirmed signatures of excessive wear on the intake cam lobes. Mechanical continuity was established throughout the rotating group, valve train and accessory section during hand rotation of the crankshaft. The bottom spark plugs were not removed. The combustion chamber of each cylinder was examined through the spark plug holes utilizing a lighted borescope. The combustion chambers remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The valves were intact and undamaged. There was no evidence of valve to piston face contact observed.

The left and right magnetos remained securely clamped at their respective mounting pads and had been thermally damaged due to the effects of the post impact ground fire. The ignition harness was secure at each magneto. The magnetos were removed for examination. The magnetos sustained varying degrees of thermal damage that rendered the unit inoperative and therefore, could not be functionally tested. Magneto to engine timing could not be ascertained.

There was no oil residue observed in the exhaust system gas path. There was significant ductile bending of the exhaust system components. The exhaust system was found free of obstructions.

A subsequent teardown examination of the engine was conducted September 01, 2015, under the oversight of the NTSB investigator-in-charge. The engine was completely disassembled. The cylinder(s) combustion chambers and barrels remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The valves were intact and undamaged. There was no evidence of valve to piston face contact observed. The pistons were intact. The ring assemblies at each piston were intact and free to rotate within their respective ring land. Mechanical continuity of the rotating group and internal mechanisms were established visually during the disassembly and examination of the engine. The accessory gears including the crankshaft gear, bolt and dowel were intact and remained undamaged by any pre-impact malfunction. There was no evidence of lubrication depravation found. The crankshaft and attached connecting rods remained free of heat distress. The valve tappet faces exhibited significant spalling damage.

Lycoming Engines Mandatory Service Bulletin SB301B, dated February 18, 1977 provides guidance for maintenance procedures and service limitations for valves. In particular Paragraph 1,(b) states "Rotate the engine by hand and check to determine that all cylinders have normal lift and that rockers arms operate normally" a 400 hour inspection interval. The logbooks did not contain any record of a camshaft lobe inspection, camshaft replacement or compliance with this SB.

According to Lycoming Engines Service Instruction SI1009AW "Recommended Time Between Overhaul Periods" the subject engine should be overhauled at 2,000 hour intervals or before the twelfth year, whichever occurs first.

Lycoming Engines Mandatory Service Bulletin SB480E provides guidance when inspecting oil system screens and filters for contamination during inspection cycles.