# NTSB ANC19LA016: Piper PA-32-300, N4466T, Bethel, AK, April 12, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: April 11, 2019, 16:08 local (Apr 12, 2019, 00:08 UTC) - Place: Bethel, AK - Coordinates: 61.033332, -161.13333 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.0333&lon=-161.1333&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: Lycoming Engines, Paklook Air Inc, FAA - NTSB case key (mKey): 99260 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC19LA016 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99260/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99260 - Page: https://openairdocs.org/ntsb/ANC19LA016 ## Probable cause A total loss of engine power due to a fatigue failure of the crankshaft. A contributing factor was the inadequate inspection during the engine’s last overhaul. ## 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: [Piper PA-32-300, 8 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7103212), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Piper PA-32-300, 8 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7103212), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piper PA-32-300, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=7103212), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-32-300, 25 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7103212), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Enroute: Emergency descent initiated](https://openairdocs.org/ntsb-events/130); cases with it: [Piper PA-32-300, 2 cases](https://openairdocs.org/ntsb-events/130/sequence.md?model=7103212), [All aircraft, 42 cases](https://openairdocs.org/ntsb-events/130/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-32-300, 23 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7103212), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Piper PA-32-300, 6 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=7103212), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that, while in cruise flight, the engine lost partial power, then total power, and the propeller stopped turning. During the subsequent off-airport forced landing on the tundra meadow, the main landing gear separated from the airplane, resulting in substantial damage to the right wing. Examination of the engine revealed a crankshaft failure that was likely a result of fatigue cracking that emanated from the surface of the main journal. The engine was overhauled at a certified repair station about 14 flight hours before the accident. The engine manufacturer overhaul manual stated that the crankshaft was to be inspected using a magnetic particle inspection procedure as part of the overhaul; however, the crankshaft was not inspected as part of the overhaul. It is likely that if the crankshaft had been inspected as indicated, the fatigue cracking would have been detected and corrected during overhaul. ## Factual narrative On April 11, 2019, about 1608 Alaska daylight time, a Piper PA-32-300 airplane, N4466T, sustained substantial damage when it was involved in an accident near Bethel, Alaska. The pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 135 domestic passenger flight. The pilot reported that, while en route from Aniak Airport (ANI), Aniak, Alaska, to Bethel Airport (BET), Bethel, Alaska, the engine began to sound “different,” and he observed a loss of engine oil pressure below the green arc. The engine rpm decreased to about 2,000 rpm, and the oil pressure continued to decrease to the yellow arc. As he turned the airplane toward Akiak Airport (AKI), Akiak, Alaska, the closest airport, and while adjusting the propeller rpm, the engine lost all power. During the subsequent off-airport forced landing on the tundra-covered meadow, the main landing gear separated from the airplane, resulting in substantial damage to the right wing. Examination revealed that the engine was seized and could not be rotated. The case halves were separated, revealing a failure of the crankshaft on the No. 3 main bearing journal. The failure showed signs of thermal damage and twisting. The engine valves were all set correctly and properly installed. The oil pan contained large amounts of copper and metal flake. The oil pan screen was removed, and heavily fragmented metal shavings were found. The fractured crankshaft and two halves of a bearing from main journal No. 3 were sent to the NTSB Materials Laboratory. The examination revealed that crack arrest marks typical of fatigue cracking emanated from multiple origins at the surface of the main journal. The fatigue origin area was located near the center of the main journal. The fracture face at the fatigue origin area exhibited evidence of blue, grey, and red tinting consistent with heat exposure. The fracture features at the origin of the fatigue crack and other portions of the fracture were obliterated by post-fracture relative movement between mating fracture faces. The fatigue crack propagated toward the core of the main journal, where it split into two fatigue cracks. The surface of the main journal exhibited evidence of severe mechanical damage such as circumferential abrasion, wear, galling and heat tinting. The surface also contained evidence of ladder cracking. The overhauled engine was installed in April 2019 and had accumulated about 14 hours of operation before the accident. Section 7 of the Lycoming Overhaul Manual for direct drive engines, page 7-4 section 7-28A states: Crankshaft (Magnetic Particle Inspection). Inspect the crankshaft using a magnetic particle inspection procedure performed by a certified operator. The work order for the engine overhaul indicated that a magnaflux and zyglo inspection was completed, but the inspection did not include the case or crankshaft. The owner of the certified repair station stated that they perform allnon-destructive testing (NDT) inspections, magna flux, and measurements for the overhauled engines at their location. After they NDT inspect the parts, “NDT” was stamped on the part. Components without an NDT stamp indicated that NDT inspection was not completed. The accident crankshaft had no visible NDT stamp. ## Aircraft - Registration: [N4466T](https://openairdocs.org/deregistered/N4466T-2021-09-04), registration cancelled 2021-09-04, S/N 32-7240067, built 1972 (OpenAirDocs) - Reported make and model: Piper PA-32-300 - Registry model: [Piper PA-32-300](https://openairdocs.org/model/piper-pa-32-300) (registry code 7103212) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 32-7240067 - Year built: 1972 - Airframe hours: 19991.3 - Engines: Lycoming IO-540 -K1A5 300 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Paklook Air Inc, doing business as Yute Commuter Service - Registered owner: Michael W. Renfro - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, April 7, 2019 - Departed: ANI, Aniak, AK - Destination: BET, Bethel, AK - Flight plan: Company VFR - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review November 18, 2018; seat: left; flight hours: 16,800 total, 80 in the last 90 days, 40 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 50° at 18 knots - Visibility: 10 statute miles - Lowest ceiling: 6,500 ft broken - Temperature: 43 °F, dew point 36 °F - Altimeter: 29.04 inHg - Observed at: PAKI, 9 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 20190411015019A](https://openairdocs.org/incident/20190411015019A), Apr 11, 2019: Piper PA-32-300, Bethel, AK, Substantial damage. On 11 April 2019 aircraft N4466T, a Piper PA-32, departed aniak, AK enroute to Bethel, AK. While in route and cruising at 800 feet the engine started to sound… ## Other investigations on N4466T (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 ANC06LA143](https://openairdocs.org/ntsb/ANC06LA143), Aug 26, 2006: Piper PA-32-300 (N4466T), Fairbanks, AK, substantial damage. Probable cause: The fracture of the aluminum alloy landing gear adapter assembly, which resulted in a loss of control during the landing roll. ## Docket (12 files) The files NTSB released with the investigation on November 4, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99260. 29.9 MB in all. - Materials laboratory factual report 21-049 (item 1, PDF, 6 pages, 5 photos, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12407641&FileExtension=pdf&FileName=21-049%20-%20crankshaft-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 2, PDF, 9 pages, 11.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7994933&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Pilot email (item 3, PDF, 1 page, 35 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7994170&FileExtension=pdf&FileName=Pilot_Email_Redacted-Rel.pdf - Roc one stop aviation (item 4, PDF, 1 page, 144 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=8942737&FileExtension=pdf&FileName=Owner%20One%20Stop%20Aviation-Rel.pdf - Engine examination summary (item 5, PDF, 1 page, 46 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12475950&FileExtension=pdf&FileName=Engine%20Examination%20Summary-Rel.pdf - Engine pictures (item 6, PDF, 8 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=8540644&FileExtension=pdf&FileName=Pictures-Rel.pdf - Page 1 of work order (item 7, PDF, 1 page, 284 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=8942305&FileExtension=pdf&FileName=work%20order%2030892%20Redacted-Rel.pdf - Lycoming overhaul manual (item 8, PDF, 1 page, 264 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=8942913&FileExtension=pdf&FileName=Lycoming%20Overhaul%20Manual-Rel.pdf - Maintenance records (item 9, PDF, 12 pages, 14.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12422188&FileExtension=pdf&FileName=Paklook%2066T%20aircraft,%20engine%20and%20prop%20records_Redacted-Rel.pdf - Statement of party representative to NTSB investigation (paklook air) (item 10, PDF, 1 page, 158 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12895672&FileExtension=pdf&FileName=Party%20Form%20Paklook_Redacted-Rel.pdf - Statement of party representative to NTSB investigation (Lycoming) (item 11, PDF, 1 page, 260 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12895012&FileExtension=pdf&FileName=Party%20Form%20(Lycoming)_Redacted-Rel.pdf - Accident picture (item 12, PDF, 1 page, 86 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12422506&FileExtension=pdf&FileName=Accident%20Picture-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.