# NTSB WPR13LA052: Cessna U206, N5229U, Van Nuys, CA, November 25, 2012 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: November 25, 2012, 15:05 local (23:05 UTC) - Place: Van Nuys, CA - Coordinates: 34.242778, -118.523612 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.2428&lon=-118.5236&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report December 15, 2014 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO, Cessna Aircraft Company, Continental Motors Inc - NTSB case key (mKey): 85654 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR13LA052 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85654/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85654 - Page: https://openairdocs.org/ntsb/WPR13LA052 ## Probable cause A partial loss of engine power during cruise flight due to fatigue fractures of two crankshaft gear teeth from corrosion pitting, which resulted in an off-airport forced landing and collision with obstacles on the ground. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna U206, 1 case](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=2073306), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna U206, 1 case](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=2073306), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Effect on equipment; cases with it: [Cessna U206, 1 case](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=2073306), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md) - [Object/animal/substance: fence/fence post](https://openairdocs.org/ntsb-findings/03022047): Environmental issues › Physical environment · Effect on equipment; cases with it: [Cessna U206, 1 case](https://openairdocs.org/ntsb-findings/03022047/cases.md?model=2073306), [All aircraft, 313 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna U206, 3 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2073306), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna U206, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2073306), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Cessna U206, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=2073306), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The pilot reported that the airplane was in cruise flight when the engine started backfiring and he smelled burnt oil; the engine subsequently lost partial power. During the forced landing on a soccer field, the airplane sustained substantial damage when it collided with a fence and trees before coming to rest on its left side. Postaccident examination of the engine revealed that the engine crankshaft would not rotate. A borescope inspection revealed that a valve in the No. 2 cylinder was in contact with a piston face. All of the piston heads exhibited semicircular indentations near the location of the valves. Upon disassembly, six gear teeth on the crankshaft gear were found fractured, and all of the teeth on the camshaft gear were found ground off. A metallurgical examination of the separated crankshaft gear teeth revealed that two of the fracture surfaces exhibited fatigue with areas of corrosion pitting and that the other fracture surfaces exhibited evidence of overload. ## Factual narrative The airplane was a Cessna 206, serial number 206-0229. The operator reported that the airplane had a total airframe time of 8,525 hours at the last annual inspection. It had an annual inspection dated October 4, 2012. The tachometer read 2,850 at the last inspection. The engine was a Continental Motors, Inc. (CMI), IO-520-A, serial number 112894, assembled on April 26, 2000. At the time of the last inspection, the engine had accumulated a total of 1,054 hours. On November 25, 2012, about 1505 Pacific standard time, a Cessna U206, N5229U, collided with a fence during an off field forced landing near Van Nuys, California. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot and one passenger sustained minor injuries; the airplane sustained substantial damage from impact forces. The cross-country personal flight departed Gnoss Field Airport, Novato, California, with a planned destination of John Wayne-Orange County Airport, Santa Ana, California. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated the airplane was in cruise flight when the engine started backfiring. He smelled burnt oil, and the engine subsequently lost power. During the forced landing on a soccer field, the airplane collided with a fence and trees before coming to rest on its left side. January 15, 2013 Examination The National Transportation Safety Board investigator-in-charge (IIC), and investigators from Cessna and CMI examined the wreckage at a hangar in Santa Ana, California, on January 15, 2013. A full report is contained within the public docket for this accident. Investigators were unable to manually rotate the engine. At the time of the investigative exam, the tachometer read 2,878.3 hours (28.3 hours after the annual inspection). Examination of the engine revealed that the exhaust pushrod housing tubes on the number two and number five cylinders were fractured through their entire circumference. The exhaust pushrod shroud on the number three cylinder was cracked approximately halfway around its circumference. All three cracks/fractures were located along the pressed bead that serves as a seat for the pushrod housing spring. Investigators crated the engine for shipment to the factory for further examination. April 8, 2013 Examination - Mobile, Alabama CMI personnel examined the engine under the supervision of the IIC at the factory in Mobile, Alabama, on April 8, 2013. A full report is contained within the public docket for this accident. A borescope inspection revealed that a valve in the number two cylinder was in contact with a piston face. All piston heads exhibited semicircular indentations near the location of the valves. The camshaft, which operated the cylinder valves, was driven by a gear that meshed with a gear on the crankshaft. Upon disassembly, six gear teeth on the crankshaft gear were fractured. All teeth on the camshaft gear wereground off. A CMI metallurgist examined several of the separated crankshaft gear teeth. Two fracture surfaces showed fatigue with areas of corrosion pitting. The others exhibited overload. ## Aircraft - Registration: [N5229U](https://openairdocs.org/deregistered/N5229U-2014-04-24), registration cancelled 2014-04-24, S/N 206-0229, built 1964 (OpenAirDocs) - Reported make and model: CESSNA U206 - Registry model: [Cessna U206](https://openairdocs.org/model/cessna-u206) (registry code 2073306) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 206-0229 - Year built: 1964 - Airframe hours: 8525 - Engines: Continental Motors Inc IO-520-A 32B 285 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Clipper 29 Uniform LLC - Registered owner: Clipper 29 Uniform LLC - Airworthiness certificate: Standard, Utility - Last inspection: Annual, October 4, 2012 - Departed: DVO, Novato, CA - Destination: SNA, Santa Ana, CA - Airport: VNY, Van Nuys ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: minor; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 9, 2012; seat: left; restraint: 3-point; flight hours: 4,477 total, 294 in this make and model, 63 as pilot in command, 7 in the last 90 days, 7 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 52 °F - Altimeter: 29.87 inHg - Observed at: KVNY, 3 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20121125027749A](https://openairdocs.org/incident/20121125027749A), Nov 25, 2012: Cessna U206, Northridge, CA, Substantial damage. At approx. 4500 feet AGL, pilot reported engine popping, backfiring and, unable to stop descent. Subsequently, engine failed and a forced landing occurred at a… ## Other investigations on N5229U (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB SEA66D0043](https://openairdocs.org/ntsb/SEA66D0043), Jul 11, 1965: Cessna 206 (N5229U), Sellway, ID, substantial damage ## Docket (9 files) The files NTSB released with the investigation on November 12, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85654. 15.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 496 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418856&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Airframe and Engine Exam Report (item 2, .PDF, 264 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418857&FileExtension=.PDF&FileName=Airframe%20and%20Engine%20Exam%20Report-Master.PDF - Mobile Engine Exam Report (item 3, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418858&FileExtension=.PDF&FileName=Mobile%20Engine%20Exam%20Report-Master.PDF - JPI Data (item 4, .PDF, 10.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418859&FileExtension=.PDF&FileName=JPI%20Data-Master.PDF - Airframe Annual Inspection (item 5, .PDF, 431 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418860&FileExtension=.PDF&FileName=Airframe%20Annual%20Inspection-Redacted.PDF - Engine Annual Inspection (item 6, .PDF, 444 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418861&FileExtension=.PDF&FileName=Engine%20Annual%20Inspection-Redacted.PDF - Engine Logbook Excerpts (item 7, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418862&FileExtension=.PDF&FileName=Engine%20Logbook%20Excerpts-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 8, .PDF, 425 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418863&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Revised Factual Report (item 9, .PDF, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419205&FileExtension=.PDF&FileName=Revised%20Factual%20Report-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.