# NTSB SEA08LA156: Cessna TR182, N7XZ, Bend, OR, June 30, 2008 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: June 30, 2008, 16:58 local (23:58 UTC) - Place: Bend, OR - Coordinates: 44.094444, -121.199996 - Nearby events: https://openairdocs.org/map.md?lat=44.0944&lon=-121.2000&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report May 6, 2009 - Report: Approved by Office Director - Parties: Federal Aviation Administration, Textron Lycoming Engines - NTSB case key (mKey): 68347 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA08LA156 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68347/pdf - Page: https://openairdocs.org/ntsb/SEA08LA156 ## Probable cause The failure of the crankshaft during cruise flight due to fatigue. ## 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 TR182, 1 case](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=2072735), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna TR182, 2 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=2072735), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna TR182, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072735), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna TR182, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072735), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that, during cruise flight, the engine began to run rough as she noticed that the propeller rpm was beyond the red line indication and that oil was coming from the forward cowling area behind the propeller. The oil began coating the windscreen and made forward visibility nearly impossible as the pilot initiated an off-airport landing in an adjacent open field. During the landing roll, the airplane struck a barbed wire fence and came to rest on a two-lane highway, which resulted in substantial damage to the right wing and engine firewall. A postaccident examination of the engine revealed that the crankshaft was cracked about 380 to 400 degrees around the circumference of the forward bearing journal, originating from the oil-through hole and progressing in a direction opposite of the rotation of the crankshaft. A metallurgical examination of the fracture region revealed that the origin of the fracture was consistent with a brittle intergranular fracture through the nitride layer and exhibited numerous crack arrest marks. Beyond the fatigue fracture area, the fracture was on a slant plane consistent with overstress separation. The source of the loading that lead to the initial crack formation at the oil through-hole could not be determined. Review of aircraft logbook records revealed that an engine overhaul was completed on May 1, 2006. The most recent annual inspection of the engine and airframe was conducted on May 30, 2008, 252.3 hours since the engine's last major overhaul. ## Factual narrative On June 30, 2008, at 1658 Pacific daylight time, a Cessna TR182, N7XZ, was substantially damaged during a forced landing near Bend, Oregon. The airplane was registered to and operated by Spirit Flight Inc. doing business as Wings of the Cascades, Redmond, Oregon, under contract with the United States Forest Service. The local fire reconnaissance flight was operated under the provisions of 14 Code of Federal Regulations (CFR) Part 135 and visual flight rules (VFR) with a company flight plan in effect. Visual meteorological conditions prevailed. The airline transport pilot sustained serious injuries and the sole passenger sustained minor injuries. The cross-country flight departed from the Roberts Field Airport (RDM), Redmond, Oregon, about 1543 with an intended destination of Prineville, Oregon. In a written statement, the pilot reported that during cruise flight, the engine began to run rough as she noticed the propeller revolutions per minute (RPM) was beyond the redline indication and oil began to splatter on the windscreen. The pilot intended to return to Redmond or Bend, Oregon, however, was unable to do so and initiated an off airport landing in an open field near her position. As the airplane approached the field, oil continued to coat the left and right sides of the windscreen. The pilot stated that the oil was originating from the cowling aft of the propeller and made "forward visibility nearly impossible." Prior to landing in the field, the pilot turned the fuel selector to the OFF position and positioned the mixture to idle cut-off. During the landing roll, the airplane struck a barbwire fence and came to rest upright on a two-lane highway. Examination of the airplane by local law enforcement revealed that the right wing was buckled throughout, the engine firewall was bent, and oil was observed on the windscreen. The airplane was recovered to a secure location for further examination. On October 15, 2008, at the facilities of Specialty Aircraft Services, Redmond, Oregon, the engine was examined by a representative from Textron Lycoming Engines under the supervision of the Safety Board investigator-in-charge (IIC). Examination of the Lycoming O-540-L3C5D engine, serial number L-21341-40A, revealed that it remained attached to the airframe via all engine mounts. All of the engine accessories remained attached to the engine crankcase. The engine was disassembled and visually inspected. The crankshaft, serial number V7379, was found intact; however, exhibited a crack about 380 to 400 degrees around the circumference of the forward bearing journal that radiated outwards from the oil-through hole. Both forward main bearings were found severely worn through the babbitt layer, exposing the copper layer of the bearings. The first or forward most connecting rod bearing also exhibited wearing through the babbitt layer. No further anomalies were noted with the engine. The crankshaft, left and right crankcase halves, and forward main bearings weresent to the NTSB Office of Research and Engineering, Materials Laboratory Division for further examination. Examination of the crankshaft by an NTSB Materials Engineer revealed that the spiral crack originated from the oil through-hole at the forward bearing journal. The crack faces on either side of the oil through-hole extended for 2 millimeters (mm) along a right-hand spiral at a 9 degree rise to the transverse plane. The crack path then changed to a left-hand spiral direction at a 45 degree rise to the transverse plane. The left hand spiral extended for 20 mm in the clockwise direction and 40 mm in the counter-clockwise direction (as seen looking from aft to forward). The crack then changed to a right hand spiral at a 45 degree rise that continued around the perimeter of the journal before terminating on the opposite side of the cracks origin. Scanning electron microscopy (SEM) of the intact end of the oil through-hole revealed multiple short cracks emanating from either side of the undamaged oil through-hole end. The origin of the fracture was found to be consistent with a brittle intergranular fracture through the nitride layer. Examination of the fracture surface revealed multiple crack arrest marks on the left-hand spiral segment of the fracture surface. The shape and orientation of the marks indicated that the fracture originated at the oil through-hole. The crack arrest marks terminated at the point where the spiral path changed from a left-handed to right-handed spiral. The fracture surface on the right-handed spiral surface was on a slant plane consistent with overstress separation. The chemical composition of the crankshaft was tested and found to be within the manufacturer's specified limits. (Refer to the attached Materials Laboratory Factual Report.) According to the owner/operator of the airplane, the engine was removed from the airframe in mid to late 2005 to undergo an engine overhaul. This was due to the engine total time since overhaul approaching the manufacturer's recommended time limits. The engine was initially disassembled and partially overhauled over the course of a few months by two separate airframe and powerplant (A&P) mechanics. It then remained disassembled and in storage until about April, 2006, when a third A&P mechanic completed the overhaul. Review of aircraft logbook records revealed that an engine overhaul was completed on May 1, 2006, at an engine total time of 3,521 hours. The engine was installed on the airframe on May 15, 2006, at a tach time of 813.3 hours. The most recent annual inspection of the engine and airframe was conducted on May 30, 2008, at a tach time of 1,065.6 hours, 252.3 hours since engine underwent a major overhaul. A service tag from Engine Components Incorporated (ECI) of San Antonio, Texas, dated November 10, 2004, indicated that the crankshaft, serial number V7379, part number LW17626 was repaired in accordance with MPP-9045 and was found within "new limits." According to a workorder obtained from ECI regarding the crankshaft, the main bearing journals were polished and the propeller flange was slightly ground. The crankshaft underwent a magnaflux inspection and no anomalies were noted. ## Aircraft - Registration: [N7XZ](https://openairdocs.org/deregistered/N7XZ-2015-05-11), registration cancelled 2015-05-11, S/N R18201053, built 1979 (OpenAirDocs) - Reported make and model: CESSNA TR182 - Registry model: [Cessna TR182](https://openairdocs.org/model/cessna-tr182) (registry code 2072735) (OpenAirDocs) - Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: R18201053 - Airframe hours: 3793.3 - Engines: Lycoming O-540-L3C5D 235 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Spirit Flight Inc., doing business as Wings of the Cascades - Registered owner: Spirit Flight Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 30, 2008, 21 hours before - Departed: RDM, Redmond, OR - Destination: Prineville, OR - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: serious; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review June 10, 2008; seat: left; flight hours: 13,800 total, 1,025 in this make and model, 13,500 as pilot in command, 59 in the last 90 days, 31 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 7 knots, gusting 16 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 93 °F, dew point 37 °F - Altimeter: 29.94 inHg - Observed at: RDM, 15 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 20080630840759A](https://openairdocs.org/incident/20080630840759A), Jun 30, 2008: Cessna TR182, Bend, OR, Substantial damage. (-23) On June 30, 2008 at 1720 PDT, aircraft N7XZ was substantially damaged during a forced landing near Bend, OR. The aircraft was being operating under part… 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.