# NTSB WPR18LA039: Cessna 172R, N2103T, Redding, CA, November 2, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: November 2, 2017, 09:30 local (16:30 UTC) - Place: Redding, CA - Coordinates: 40.508888, -122.29333 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.5089&lon=-122.2933&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration, Continental Aerospace Technologies - NTSB case key (mKey): 96392 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA039 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96392/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96392 - Page: https://openairdocs.org/ntsb/WPR18LA039 ## Probable cause The fatigue separation of the crankshaft due to a fatigue fracture, which resulted in a total loss of engine power and a subsequent off-airport landing and impact with a fence. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 172R, 3 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=2072401), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Object/animal/substance: fence/fence post](https://openairdocs.org/ntsb-findings/03022047): Environmental issues › Physical environment · Not specified; cases with it: [Cessna 172R, 2 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md?model=2072401), [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-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna 172R, 5 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=2072401), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-climb to cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Cessna 172R, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2072401), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) ## Analysis Two student pilots and the flight instructor were conducting a cross-country instructional flight. The instructor reported that he told the student who was flying to climb to 3,500 ft above ground level (agl). As the airplane approached 3,100 ft agl, the student began leaning the mixture. Subsequently, the engine began to sputter, followed by a loss of all power. The instructor then saw sparks near the propeller area, took the flight controls, and turned back toward the departure airport. During short final, due to fire near the propeller area and the smell of smoke in the cockpit, the instructor turned the airplane 360° to try to lose altitude; however, the airplane was still too high to safely land on the runway. Subsequently, he conducted a forced landing to a field just past the runway, during which the airplane struck a fence, which resulted in substantial damage to the wing and firewall. Examination of the engine revealed that the crankshaft had separated at the propeller hub assembly and that a portion of it remained in the assembly. No holes were found in the engine case. Metallurgical examination revealed that the crankshaft had fractured into two halves at the main bearing journal’s forward side. The fracture consisted of two primary mating crack faces, one of which was circumferential and the other of which was a spiral through a lubrication hole to the inside of the crankshaft journal. The lubrication hole exhibited crack arrest marks that originated from the inside portion of the hole wall. The mating fracture surfaces of the circumferential and spiral fractures exhibited crack arrest marks consistent with progressive crack growth due to fatigue. The areas outside of the circumferential fracture exhibited features consistent with subsequent overstress fracture. Maintenance records revealed that at the time of the accident the engine had accumulated a total time of 3,907.1 hours and 1,153.7 hours since major overhaul. Based on the evidence, it is likely that the crankshaft fractured due to a fatigue crack that had initiated at a lubrication hole on the main bearing journal and then progressed in an outward spiral direction toward the inside surface of the crankshaft journal. The fatigue crack then progressed circumferentially until the crankshaft fractured into two halves due to overstress, which resulted in a subsequent total loss of engine power and off-airport landing. ## Factual narrative On November 2, 2017, about 0930 Pacific daylight time, a Cessna 172R airplane, N2103T, was substantially damaged when it was involved in an accident near Redding, California. The flight instructor and two students were not injured. The airplane was being operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that he told the student pilot who was flying to climb the airplane to 3,500 ft. As it approached 3,100 ft, the student began leaning the mixture. Subsequently, the engine began to sputter, followed by a loss of all power. The instructor then saw sparks emanating from the propeller area, took the flight controls, and turned back toward the departure airport. The instructor added that the student conducted the “emergency checklist” while he contacted the tower controller and maintained 100 knots. Due to fire near the propeller area and the smell of smoke in the cockpit, during short final, the instructor turned the airplane 360° to try to lose altitude; however, the airplane was still too high to safely land on the runway. Subsequently, he conducted a forced landing to a field just past the runway, during which the airplane struck a fence, which resulted in substantial damage to the left wing and firewall. Examination of the engine revealed that the crankshaft had separated at the propeller hub assembly with a portion of the crankshaft remaining in the assembly. No holes were found in the engine case. After the connecting rods were disassembled, examination revealed that the No. 1 connecting rod bearing exhibited metal smearing on its face. The No. 4 connecting rod and bearing assembly had metal shavings on it and exhibited thermal discoloration and some deformation. The other two connecting rods and bearings exhibited some thermal discoloration. Metallurgical examination further revealed that the crankshaft had fractured into two halves at the main bearing journal’s forward side. The fracture consisted of two primary mating crack faces, one of which was a circumferential crack and the other of which was a spiral through a lubrication hole to the inside of the crankshaft journal. The mating fracture surfaces of the circumferential fracture exhibited crack arrest marks, which had propagated from the spiral facture, consistent with progressive crack growth. The areas outside of the circumferential fracture exhibited features consistent with subsequent overstress fracture. The mating fracture surfaces of the spiral fracture also exhibited crack arrest marks, which originated from the inside portion of the hole wall, consistent with progressive crack growth. The lubrication hole exhibited witness marks consistent with rotational wear and crack arrest marks that originated from the inside portion of the hole wall. Maintenance records revealed that On March 15, 2016, the engine was signed off as overhauled and maintenance personnel performed a final inspection of the engine with nodiscrepancies identified. According to a logbook entry made the next day, the engine was overhauled to zero-time and had a previous total time of 2,754 hours. At the time of the accident the engine had accumulated a total time of 3,907.1 hours and 1,153.7 hours since the major overhaul. ## Aircraft - Registration: [N2103T](https://openairdocs.org/aircraft/N2103T), registered now, S/N 17281205, built 2004 (OpenAirDocs) - Reported make and model: CESSNA 172R (R) - Registry model: [Cessna 172R](https://openairdocs.org/model/cessna-172r) (registry code 2072401) (OpenAirDocs) - Registry engine: [Lycoming IO-360-L2A](https://openairdocs.org/engine/lycoming-io-360-l2a) (registry code 41597, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17281205 - Year built: 2004 - Airframe hours: 7248.4 - Engines: LYCOMING IO-360-L2A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Iasco Flight Training Inc - Registered owner: Iasco Flight Training Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 17, 2017 - Departed: KRDD, Redding, CA - Destination: KCIC, Chico, CA - Airport: KRDD, Redding Municipal Airport - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 28; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 13, 2017; seat: right; restraint: 3-point; flight hours: 1,391.6 total, 990 in this make and model - Student pilot; age 24; injuries: none; student; medical: class 2, with waivers/limitations; seat: left; restraint: 3-point; flight hours: 0 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 2,100 ft broken - Temperature: 54 °F, dew point 32 °F - Altimeter: 30.11 inHg - Observed at: KRDD ## 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 20171102018169A](https://openairdocs.org/incident/20171102018169A), Nov 2, 2017: Cessna 172R, Redding, CA, Minor damage. While at cruise altitude approximately 3000 feet the student pilot in command started leaning the mixture, then the engine started spuddering, the crew of… ## Docket (7 files) The files NTSB released with the investigation on January 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96392. 24.9 MB in all. - Materials laboratory factual report (item 1, PDF, 20 pages, 25 photos, 8.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7005230&FileExtension=pdf&FileName=18-073%20-%20Materials%20Lab%20Factual%20Report%20(WPR18LA039)-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 2, PDF, 10 pages, 4.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11572368&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - NTSB engine examination report (item 3, PDF, 5 pages, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11631761&FileExtension=pdf&FileName=Engine%20Examination%20Report-Rel.pdf - Excerpt engine records (item 4, PDF, 13 pages, 7.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11571794&FileExtension=pdf&FileName=Engine%20Records%20Excerpts_Redacted-Rel.pdf - Evidence control form (item 5, PDF, 1 page, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11631644&FileExtension=pdf&FileName=WPR18LA039%20Chain%20of%20Custody_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 6, PDF, 10 pages, 538 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11571371&FileExtension=pdf&FileName=WPR18LA039%20Cert%20of%20Party%20Rep%20-%20Charnon_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 7, PDF, 1 page, 402 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11572088&FileExtension=pdf&FileName=WR%20Form%20WPR18LA039_Redacted-Rel.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.