Analysis
Shortly after takeoff, the manifold pressure dropped. The private pilot then turned the airplane back to the airport. He saw smoke coming from under the engine cowl, and the engine stopped producing power while the airplane was on short final and about 800 ft above ground level. The airplane impacted power lines before landing in a grassy area short of the runway.
Holes were observed in the top of the engine crankcase. Disassembly of the engine revealed all the crankshaft's connecting rod journals and connecting rods displayed signs of thermal distress and discoloration associated with engine operation without sufficient oil. All six cylinder bays exhibited mechanical damage consistent with an oil starvation event. The engine and component examinations did not identify any anomalies that would have precipitated an oil starvation event and subsequent engine failure. The No. 2 piston was fractured into numerous pieces. The area adjacent to the broken connecting rod displayed surface coloration and oxide formation consistent with exposure to very high temperatures. The engine had experienced a previous "hydraulic lock" event about 1 1/2 years before the accident, but it could not be determined if damage sustained during that event caused the catastrophic failure of the No. 2 piston.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
A catastrophic engine failure due to an oil starvation event for reasons that could not be determined based on the available evidence.
Findings
Aircraft
Recip eng oil sys - Not specified (Cause)
Environmental issues
Wire - Contributed to outcome
Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office
Continental Motors, Inc.
Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf
Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms
http://registry.faa.gov/N731QV
Location: West Memphis, AR
Accident Number: CEN15LA015
Date & Time: 10/15/2014, 1725 CDT
Registration: N731QV
Aircraft: CESSNA P210N
Aircraft Damage: Substantial
Defining Event: Loss of engine power (total)
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Personal
On October 15, 2014, about 1725 central daylight time, a Cessna P210N airplane, N731QV, sustained substantial damage following a forced landing and impact with terrain after a reported loss of engine power during initial climb out from West Memphis Municipal Airport (AWM), West Memphis, Arkansas. The pilot, who was the registered owner and sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed for the local flight, which was being operated as a personal flight in accordance with 14 Code of Federal Regulations Part 91, and no flight plan had been filed.
The pilot reported he was departing for a local training flight. After takeoff, about 10 minutes into the flight while climbing through 4,500 feet MSL, the manifold pressure dropped and the pilot made a turn to return to AWM. Smoke was observed coming from under the engine cowl and the engine stopped while on short final about 800 feet AGL. The airplane impacted power lines before landing in a grassy area short of the runway and on airport property.
A JPI EDM-830 engine data module was recovered and subsequently downloaded by a recorder specialist and the NTSB's Vehicle Recorder Laboratory. Data indicated the flight took off about 1714 and about six minutes after takeoff engine RPM began to fluctuate and one minute later the exhaust gas temperatures increased. By 1723, engine RPM decreased, voltage decreased, and manifold pressure increased.
The airplane was powered by a six-cylinder Continental Motors IO-550-P6B, serial number 1006549, that was assembled at the Continental Motors factory on May 9, 2012, as a new IO-550-P6B. The engine was shipped to Vitatoe Industries, Inc. on May 14, 2012, where the engine was modified utilizing Vitatoe Supplemental Type Certificate (STC) SA02918CH, converting the engine to a turbo-normalized induction system. According to the maintenance records, the modified engine was installed on the accident airplane on August 7, 2012 (the tachometer time was not reported).
The electric boost pump was removed and replaced on April 5, 2014. After the fuel boost pump was replaced, the operator reported he attempted to start the engine after running the boost pump. The crankshaft/propeller rotated but came to an abrupt stop and could not be rotated through (a condition consistent with hydraulic lock). The operator reported that the starter could not rotate the propeller through on consecutive attempts. The operator left the aircraft and returned a couple days later with a battery charger. The engine started on the first attempt without need for battery charging. The operator continued to operate the airplane with no anomalies up until the time of the accident.
Hydraulic lock is most common in reciprocating engines and occurs when the amount of liquid introduced into the cylinder is greater than the available volume when the piston head is at the top of its stroke. It typically results in breaking or bending of the connecting rod, but can also damage the pistons and crankshaft. When an engine experiences hydraulic lock, damage to the engine connecting rods, crankshaft, piston heads, bearings, etc., might not be apparent without an engine inspection.
The engine was removed and taken to the Continental Motors facility in Mobile, Alabama, for examination. Holes were observed in the top of the crankcase. Disassembly of the engine revealed all of the crankshaft's connecting rod journals and connecting rods displayed signs of thermal distress and discoloration associated with engine operation without sufficient lubricating oil. There were no signs of an oil leak on any of the engine's components; however, the remote oil filter lines were removed by maintenance personnel for crate shipment and were not observed as part of the examination. Disassembly of the engine revealed that all six cylinder bays sustained mechanical damage. The damage observed was consistent with an engine oil starvation event. However, all bearing saddles were in place and there was no sign of bearing slip or matting surface fretting. All the oil galleys were free from obstructions. In addition to the oil starvation event, the No. 2 piston was fractured into numerous pieces. The face of the piston was fractured into multiple pieces. The No. 2 connecting rod, piston pin, and fractured piston pieces were sent to the NTSB Materials Laboratory for further evaluation.
The No. 2 piston pieces examined at the NTSB's Material Laboratory comprised the entire head and estimate 50% of the skirt. The majority of both pin bosses were also present. The entire upper compression ring was also received. Visual and magnified optical examinations revealed features and patterns indicative of overstress separation on all of the received piston fractures. Some of the pieces were darkly colored consistent with baked on oil deposit while other mating pieces were clean. The crown of the piston was clean and had small valve dents corresponding to the intake and exhaust valve locations.
The No. 2 piston pin was intact, but the aluminum pin plugs were mechanically damaged. The No. 2 connecting rod was fractured through both main bearing straps. The fracture features were partially obscured by post fracture mechanical damage but the visible fracture features were consistent with bending overstress separations. The adjacent area of the rod displayed surface coloration and oxide formation consistent with exposure to very high temperatures. The bearing surface of the rod showed heavy flow and smearing of the material.
The engine and component examinations did not identify any anomalies that would have precipitated an oil starvation event and the subsequent engine failure.
Pilot Information
Certificate: Private
Age: 58, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land; Single-engine Sea
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: 3-point
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed:
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 09/29/2014
Occupational Pilot: No
Last Flight Review or Equivalent: 08/18/2013
Flight Time: 4000 hours (Total, all aircraft), 2000 hours (Total, this make and model), 4000 hours (Pilot In Command, all aircraft), 36 hours (Last 90 days, all aircraft), 5 hours (Last 30 days, all aircraft), 0.5 hours (Last 24 hours, all aircraft)
Aircraft and Owner/Operator Information
Aircraft Manufacturer: CESSNA
Registration: N731QV
Model/Series: P210N N
Aircraft Category: Airplane
Year of Manufacture: 1980
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: P21000534
Landing Gear Type: Tricycle
Seats: 5
Date/Type of Last Inspection: 04/05/2014, Annual
Certified Max Gross Wt.: 4001 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 4196 Hours as of last inspection
Engine Manufacturer: CONT MOTOR
ELT: Installed, not activated
Engine Model/Series: TSIO-520 SER
Registered Owner: On file
Rated Power: 300 hp
Operator: On file
Operating Certificate(s) Held: None
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KAWM, 214 ft msl
Observation Time: 2153 UTC
Distance from Accident Site: 0 Nautical Miles
Direction from Accident Site: 90°
Lowest Cloud Condition: Clear
Temperature/Dew Point: 20°C / 10°C
Lowest Ceiling: None
Visibility: 10 Miles
Wind Speed/Gusts, Direction: 7 knots, 300°
Visibility (RVR):
Altimeter Setting: 29.87 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: WEST MEMPHIS, AR (AWM)
Type of Flight Plan Filed: None
Destination: WEST MEMPHIS, AR (AWM)
Type of Clearance: Traffic Advisory; VFR
Departure Time:
Type of Airspace: Class B
Airport Information
Airport:WEST MEMPHIS MUNI (AWM)
Runway Surface Type: Concrete
Airport Elevation: 212 ft
Runway Surface Condition: Dry
Runway Used: 35
IFR Approach: None
Runway Length/Width: 6003 ft / 100 ft
VFR Approach/Landing: Forced Landing
Wreckage and Impact Information
Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 35.135000, -90.234444 (est)
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